Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: 1967Brutus on October 13, 2023, 08:02:43 pm
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Hello all,
Please let me introduce myself first, so y'all won't immediately assume I'm a nutcase wanting to pimp a Microcosm...
My name is Bert, I'm Dutch, I am a marine engineer by profession, 56 years old, and a modeller since about `12 years of age or so.
Mainly occupied myself with planes and helicopters, but the origins of the hobby, my first REAL RC model, was a boat ("Seal", by Krick from Germany, I'll never forget that one). After that, the virus of remote controlled flight really
Every now and then I venture into other fields such as RC cars, RC motorcycles, RC boats, even done a hoovercraft once, but usually only if such a model is a bit out of the ordinary: About 10 years ago for example, I found myself in the posession of 2 Fuji outboard engines, so I built a boat to run one of them. Big fun. Any kind of RC is OK, as long as it is powered by some sort of combustion process, and not a chemical reaction producing electrons.
About 5 years ago it was some weird project just to see if I could get a 5 cc fourstroke not only to run on gasoline, but to keep it at 1500 RPM and power a boat with it. That project will be revived in the near future by the way, but this thread won't be about that.
This thread will be about pimping my Microcosm M29 installation.
A few months ago I got that vibe again that I wanted to do something I hadn't done before, and this time it was STEAM. For no other reason than that I ran into one of those AliExpress ads selling them. It looked good, and not held back by any knowledge on the subject of model steam I decided to buy one and see where it would lead me.
Don't get me wrong, professionally, I am pretty well aquainted with steam and steam power, but I did not have the faintest clue whether these engines are any good, nor what actually makes a model steam plant "good" or "bad"....
Since the saddest thing on earth is an engine that has nothing to do, I went ahead and ordered a "Borkum" from Krick, to go along with it.
Well... after 2 or 3 weeks, the steam plant arrived. In one piece, undamaged, and, can't say anything else, looking extremely nice.
https://www.modelbouwforum.nl/attachments/20230606_140723-jpg.542757/
https://www.modelbouwforum.nl/attachments/20230606_144145-jpg.542758/
It was running within the hour:
https://www.youtube.com/watch?v=0sd-jruzKFM
It was not running all that bad, a bit rough, the Stephenson mechanism had an awful lot of play, and it went through one boiler filling awfully fast (about 10 minutes or so).
So I had my job cut out for me.
Step by step in the next posts.
(https://i.postimg.cc/NKFCMtGY/20230606-140723.jpg) (https://postimg.cc/NKFCMtGY) (https://i.postimg.cc/TpCHf16C/20230606-144145.jpg) (https://postimg.cc/TpCHf16C)
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Bonjour Bert and welcome here :-))
I also have this plant, https://youtu.be/TO16806-3pM and https://youtu.be/HW0RsauGFa8 in my tug "Vient de loin" and have enhanced it with important accessories to my opinion, a gas regulator, a RC safety gas valve and of course a whistle ok2 that I would kindly suggest you to add also to your steam plant.
Because of its 6,7 cm3 steam machine and small boiler, I plan to add yet an electric pump (enhanced Microcosm one) :
https://youtu.be/uW7OW941xG0 and https://youtu.be/FNy_x-RR9mE and https://youtu.be/j0yn0yaT5F0
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Yes....welcome Bert.....being a Marine Engineer, this is right up your alley %) will look forward to you posts of a new vessel for the steam plant, and any advances that are suggested by our Friend Marcel [rhavane], re ...additional running time :-))
Derek
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Be patient, guys, way ahead of you, the project is basically finished (took me about 2 months in total), I just wanted to make it a bit like a series.
I kept testing, observing, and expanding the installation as I went along. Right now, the engine has allready 42 runhours on it (the TX is equipped with a runhour counter that via telemetry detects "running condition", so that is actual runtime, not just the time the TX is switched on).
At this point in time, it's got a regulated burner, a feed pump, a condenser/feedwater pre heater, condensate recovery back into the feedwater reservoir (I don't think many people have that), it's got an automatic discharging oil-separator, wick-fed automatic lubrication, and basically it has become a "light burner and forget" installation.
I am getting about 50 minutes (normal practical manouvering) on a single charge of 50 grammes of gas and 350 ml (12 oz) of feedwater.
30+ minutes from the same on full speed non stop.
Boiler feedrate is linked to the steemvalve via programmed curve in the TX, which will keep level within 5 mm accurate for at least those 50 minutes.
The fun was going to be to take one subject at a time...
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Bonjour Bert and welcome here :-))
I also have this plant, https://youtu.be/TO16806-3pM (https://youtu.be/TO16806-3pM) and https://youtu.be/HW0RsauGFa8 (https://youtu.be/HW0RsauGFa8) in my tug "Vient de loin" and have enhanced it with important accessories to my opinion, a gas regulator, a RC safety gas valve and of course a whistle ok2 that I would kindly suggest you to add also to your steam plant.
Because of its 6,7 cm3 steam machine and small boiler, I plan to add yet an electric pump (enhanced Microcosm one) :
https://youtu.be/uW7OW941xG0 (https://youtu.be/uW7OW941xG0) and https://youtu.be/FNy_x-RR9mE (https://youtu.be/FNy_x-RR9mE) and https://youtu.be/j0yn0yaT5F0 (https://youtu.be/j0yn0yaT5F0)
Hi Marcel,
we chatted the other day a bit on YouTube about that servo-feedpump you posted.
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Part 2:
In reality, would I make this a chronological report, it would have all appearance I have been modifying, testing, experimenting left and right, a bit helter skelter and all over the place. That probably would lead to a difficult to follow and long thread.
So I am going to try and keep the subjects grouped together.
I mentioned in my introduction that I am a marine engineer, but when at home in my shore leave, I have surprisingly few resources, tools, machines and fabricating possibilities. I just am not that kind of guy that has a tool for everything. Too expensive and too bothersome. Too time-consuming also.
I did all this, basically, "the McGyver way".
Mechanically and technically, the following two alterations are the ONLY two mods that I did TO the engine:
One of the first things I noticed was that there is a LOT of clearance in the actuating mechanism of the Stephenson reversing gear.
The lever has a prong that hooks into a clevis, and the prong is 2 mm wide, the slot in the clevis is 3 mm, to allow for angular movement.
The solution, IMHO, would be if the lever would have been fitted with a 3 mm diameter ball.
The solution is easy, even without specialized tools: I took a length of 3 mm outer diameter (2 mm inner) brass tubing availlable in any decent modelling shop, cut a length of 3 mm of that tube (Brass tube is very easy to cut clean, by taking any sharp knife (hobby knife, potato peeler knife, pocket knife) and rolling the tubing between the knife edge and a flat surface (like your building table).
Regardless of how you cut the tube, a length equal to the outer diameter is what you want.
Force the piece of tubing over the prong, and file the tubing into a ball shape. This also does not require too much "sculpting skills", just rounding it off and checking whether the ball allows the necessary freedom of movement. If you happen to have taken off too much material, the failed piece is easily removed, and a new 3 mm piece is easily cut and placed.
Once to your satisfaction, lubricate with a bit of EP2 grease or similar, and it will last virtually indefinitely.
This is the best picture I can provide right now, apologies for the less optimal quality. It looks blurry, but it isn't, that's white grease
https://www.modelbouwforum.nl/attachments/20230607_155906-1-jpg.542866/
The elimination of this excessive clearance had a remarkable positive effect on the running behaviour of the engine.
The other modification unfortunately I do not have any pics of, but like many people, I noticed that the engine consumes a LOT of steam and had one "dead point" in the forward running direction where it would not self-start. That invariably happened with the forward piston in TDC.
Since the engine would start in reverse in that position, that means there is an issue with the slide valve of the rear cylinder, because the piston in TDC is not active.
So I opened the valve box and found that the slide valve did not move freely.
The control rod has a block shaped part to it that engages between four prongs on the slide valve. There should be no or minimal clearance between block and prongs (otherwise valve timing gets sloppy) but there should also not be any binding, or the valve won't seal properly on the mirror.
A few strokes with a keyfile solved that, but while I had the valve out, I noticed that the sliding surface showed machining marks, while the mirror appeared to be polished. Wow... how am I going to manage that, with no specialized tools? Dang...
What I did, was place a piece of 1200 grit waterproof sandpaper on a mirror (mirrors are flat, aren't they?) and made two figures of eight with the valve over the grit, just to break the surface.
Then out with the sandpaper, and enter Cif cream cleaner, which also is slightly abrasive. It took me 20 minutes to get a smooth finish with no visible machining marks.
This cured the dead spot, the engine now started without any issues, and also reduced steam consumption, but not as much as I hoped, so I did the front slide valve as well, same procedure.
Steam consumption is now acceptable although, let's face it, due to the fairly wide clearance between cylinders and pistons, this engine is never going to be a miracle of efficiency unless it will get new pistons. And not only do I lack the possibilities to do that, I also absolutely did not fancy disassembling the entire engine.
That's it, as far as the engine goes. Taking out a clearance, and polishing the valves. These mods can be done at basically any skill level with the most basic of tools and materials.
The ball-link in the reversing gear is a given: these engines come from the factory with that flaw.I did that mod IIRC the second day I ran the engine.
Whether the slides need addressing, depends on the individual engine and the quality control it received. From what I gathered, some run smooth and seal up well, others don't. Mine didn't, so this was how I solved it. It took some operating time, and the boat was already being run on open water when the high water consumption started bothering me most. The dead point (engine sometimes not starting immediately) did not bother me too much, but in one of those rare epiphanies, the idea caught that those two might be connected, and it turns out they were.
Now my fingertips hurt, so maybe later today I'll continue with the next mod.
(https://i.postimg.cc/SYGQJkKm/20230607-155906-1.jpg) (https://postimg.cc/SYGQJkKm)
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So... I slept, and woke up with fingertips that were at best a bit tender, time for the next issue of this "McGyver saga".
Lubrication...
The first runs on the bench allready told me that I did not like the intended lubrication method (oil cups on the main bearing caps, and "just squirt some oil on everything else that moves) for one bit: First of all, those tiny oil cups held their oil for maybe 5 minutes, tops, second they were not easy to fill without spilling, squirting oil on everything else (crossheads, rods, eccentrics, and "Stephenson movement") was not only messy in general, it also would present issues when the engine would be installed in a boat.
A typical run would consume half a syringe full of oil (2,5 ml or such) and the bench quickly became drenched in oil.
Rubbish, unacceptable, operating a steam engine like that is NOT going to be fun, if a 10~15 minute run causes a half hour cleaning session.
So I opted for a wick feeder with 7 tubes for the machine (3 main bearings, 2 crossheads, and 2 excenter-sets).
In practice, this results in a minute oil dosage but this has proven to be fully adequate. At least, 42 runhours (at the time of writing) without deterioration IMHO, for a brass machine (usually wearing much faster than engines made from other materials) is proof enough.
The way I see it, lubricating metal parts requires way less oil than anyone would think, as long as that oil is being fed continuously and where it is needed. Squirting a drop of oil on a lubrication spot, most of it runs off without ever doing anything useful and the microlitre that reaches the spot, does not get replenished.
How did I go about?
I built a small oil tank with 7 wick holders. I am a horrible sheet metal worker, and in general a bit of a "quick and dirty" builder, so the tank is downright ugly, but here it is:
https://www.modelbouwforum.nl/attachments/20230615_073353-1-jpg.543542/
a 10 ml filling wicked out in about 36 hours, leaving the tank bonedry and getting every last drop there where it counts.
The tank was placed in a trestle, a bit higher than the top of the machine, because the wicks only bring the oil to the outlets of the tank, but the oil has to travel by gravity through the delivery tubes.
https://www.modelbouwforum.nl/attachments/20230620_203342-1-jpg.544244/
I made those tubes out of 2 mm OD brass tubing (1 mm ID). Annealing this tubing allows for tying knots in it without kinking.
For crosshead lubrication, I had no other option than to drill one oiler hole in each guide, just above the TDC. Unfortunately, I do not have a picture of this.
The oil supplied to the croisshead guide spreads around the entire guide due to the rather violent movement of the crossheads and their cylindrical shape, then trickles down to the crosshead pin, and from there along the conrods, all the way to the bigends. Since both the crossheads, crosshead pins and bigends still don't rattle, lubrication is sufficient here.
For the main bearings, three tubes are bent to end up in the oil cups, and they are kept in place by short pieces of heatshrink tubing.
https://www.modelbouwforum.nl/attachments/20230620_203357-1-jpg.544245/
https://www.modelbouwforum.nl/attachments/20230620_203405-1-jpg.544246/
The eccentrics are lubricated by cutting the ends of the delivery pipes slanted, and letting them end up such that the control rods wipe off the arriving drops. The oil then flows down along the rods to the eccentrics.
https://www.modelbouwforum.nl/attachments/20230621_001654-1-jpg.544272/
Only one rod picks up the oil, but because of the tube ending up "between"the rods, both eccentric discs receive oil.
The wick feeder is filled with oil about 10 minutes before the first ignition of the burner (the capillary action needs a bit of time before the oil starts flowing), and pulled empty before going home again. During an afternoon of steaming, the drop in level is barely noticable. The only way I know for sure that it works, is that the squeeze-bottle was not as full as it was a month ago :D
The oil I am using is a full synthetic 10W40 motorcycle oil: No particular reason other than that it was what I had on hand. But given the dope package those oils can handle a large range of temperatures and are fairly able to deal with a bit of moisture (motorcycle engines, especially the older aircooled ones, tend to run overcooled and the oils need to be able to cope with condensation in the crankcase more so than oils for car engines). But basically, any machine oil will do.
In order to reduce the mess to clean up after use even further, I take a few leaves of toiletpaper, and roll them into some sort of tampon, that I place around the engine. Works well, is cheap and widely availlable (everybody has toiletpaper somewhere), and easy to replace.
https://www.modelbouwforum.nl/attachments/img-20230623-wa0001-1-jpg.544492/
The arches of the Stephenson I lubricate with grease, initially a simple EP2 grease, but recently I found out that mixing this grease with 20% steam cylinder oil not only reduces the paste-like consistency a bit, it also makes the grease stickier and it makes the grease creep better into crevices (like between the pin and its bore).
Greasing the arches is frugal. I think I used about 0,5ml in 20 hours op runtime
I replaced the stock displacement oiler for the glass one that Microcosm offered. For no other reason than that I prefer to be able to check content visually. The needle valve is a bonus, but does not work all that precise, and I found out over time that other factors have a much greater effect on lubrication quantity. I will get into that in a later episode.
Well, that was the part about lubrication. Personally, I think this work contributed the most to how this engine functions.
I am 100% sure that my fabricating skills are among the ugliest here on this forum, but for me fuchtion over form every time.
I hope people can derive their own plans from this info, but for crying out loud, please make it prettier than my contraptions ;)
My fingers hurt again, bt maybe later today I can type some more.
(https://i.postimg.cc/G4xPdyRf/20230615-073353-1.jpg) (https://postimg.cc/G4xPdyRf) (https://i.postimg.cc/6yRLbPmt/20230620-203342-1.jpg) (https://postimg.cc/6yRLbPmt) (https://i.postimg.cc/v4s7JvJ9/20230620-203357-1.jpg) (https://postimg.cc/v4s7JvJ9)
(https://i.postimg.cc/ThBJ9xQt/20230620-203405-1.jpg) (https://postimg.cc/ThBJ9xQt) (https://i.postimg.cc/z3ykKvwL/20230621-001654-1.jpg) (https://postimg.cc/z3ykKvwL) (https://i.postimg.cc/zHHSr2Dw/Image001.jpg) (https://postimg.cc/zHHSr2Dw)
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Next step was the burner control.
A decent burner control should ideally follow the steam demand as closely as possible, and this has, especially for this boiler (fitted with a steam dryer or very optimistically also called "superheater") certain advantages.
A burner control working along the on/off or "min/max" principle, will lead to a strong variation of heat supply to the steam dryer even if steam demand is constant. That in turn will lead to variations in moisture content of the steam, which will affect both the functioning of the displacement oiler, as well as the lubrication conditions in the engine itself.
A proportional burner control will have the advantage that when steam demand varies (and thus velocity in the dryer), the heat supply will follow fairly close keeping steam properties more constant.
In order to control the burner, I purchased a Regner gas valve. Pretty expensive but a decent piece of kit, and necessary anyway, since I want to be able to control the fire in case of emergency.
Initially I did not have a pressure sensor, and I thought I would not need one, because steam pressure and temperature are very closely related, so I figured measuring the temperature of the steam would suffice. I had temperature probes and the telemetry stuff availlable (which, for FrSky equipment is absolutely reasonably priced anyway).
The Taranis allows for a value measured over telemetry, to directly control a servo without any operator input, so a proportional control function is very easily progged (literally less than a 5 minute job), and with the steam tables for saturated steam at hand, the values to aim for were easily determined.
Well... I was right.... and also horribly WRONG about that. The principle absolutely works, and I have operated the system for several hours like that.
What caused trouble was that I can only measure temperature on the outside (I cannot fit a probe INSIDE the boiler), so there is a fair bit of deviation between read-out and actual temperature. What is worse, is that wind and weather strongly influence this deviation, and no amount of insulation of the probe remedied this.
So... I had no choice but to get me a pressure sensor (common automotive stuff, 10~15 Euro on AliExpress or similar outlets). Aivallable in several ranges and they usually have an output of 0,5 to 4,5 Volt for the 0 to 100% range. So all that is needed is an also very cheap telemetry voltage converter.
Stuff you can buy for peanuts, and there are hobbyists out there everywhere that can make those in the blink of an eye. That is how I got mine, buddy that does electronics as a hobby made one for me.
So now I have a pressure read-out on theTX, that can directly control a servo, with a freely programmable setpoint and proportional band.
In my case, 1,55 bar gives me pilot fire, 1,45 bar gives me full fire, and anything in between in proportion.
Here is me testing the set-up. The sensor is sensitive enough to trigger a full 0-100% response by as little as the pressure of just blowing into it.
Sorry for the dutch language.
https://www.youtube.com/watch?v=DEbtnk4DzS4
All that was needed now was to connect the pressure sensor to an unused appendage port of the boiler, and we have an automated proportional burner control.
The TX is configured such that there is a 3-position selector switch that gives "Off"-"Manual"-"Auto", and a knob for burner position in manual mode, used for firing up from cold.
Here is the system in operation, again sorry for the dutch comments, if you turn up the volume, in the background you can hear the engine accelerating/decellerating, and the response of the burner is visible in the display of the TX.
https://www.youtube.com/watch?v=wa0PhowMc0c
Now of course, a mechanical pressure operated gas controller also is an option, it does not really matter. But if possible I would recommend to select a controller with an as small as possible proportional band. This will result in a faster burner response and smaller pressure variations.
Because a constant pressure (and thus temperature) is advantageous for the running conditions off the engine, and in case of a steam dryer, a proportionally controlled burner is even MORE advantageous because the steam saturation is more constant. Better lubrication and less crud in the oil separator.
If the boiler does not have a steam dryer, then a proportional control is absolutely NO better than a simple on/off control.
OK... my fingers start hurting again
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You can buy temperature sensors that measure internally. As you have discovered there is way too much lag in using an external temperature reading to determine pressure.
Clevedon sell a sensor separately as well as part of their Electronic Gas regulator Unit:
http://www.clevedonsteam.co.uk/products.html#thumb
As does Denes Designs:
https://www.denesdesign.co.uk/home
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So...
Basically only one subject left, that of "how to extend operation time"...
It was pretty clear from the beginning that even with the improvements to the engine, operating time was fairly short: 15 minutes at best in reality, and for that I had to control myself and use the throttle fairly conservative.
So I first wanted to install an engine driven pump as offered by Microcosm. I ordered it, received it, but heck, by the time I got around to it I realized that this was not a plug&play option, and what was more, adjusting the feedrate was going to be an issue: I simply did not see how I was going to arrange that. It would entail either constructing an excenter with an adjustable stroke, or an adjustable bypass/return valve, additional piping, possibly a servo, and that was more effort and investment than I was willing to make.
So I looked around on the internet and found the Regner electric pump with speedcontrol. I will get back on that pump because there's something horribly wrong with that thing quality wise that I'd like to warn everybody of. But that is for later.
In itself, the pump is straightforward and I installed the pump. I posted this pic before.
https://www.modelbouwforum.nl/attachments/img-20230623-wa0001-1-jpg.544492/ (https://www.modelbouwforum.nl/attachments/img-20230623-wa0001-1-jpg.544492/)
The next problem was going to be a feedwater tank: There was nothing commercially availlable that would make any sense, at least not to me.
As I said in my introduction, I am a marine engineer, and somehow "stuck in a certain train of thought" when it comes to operating steamsystems:
The Microcosm boiler has a steamable quantity of about 180 ml (6 oz) of water. I can deal with that. You boil the water, and when its gone its gone.
Things change when you add a tank. In my mind it suddenly becomes a "system" and in my mind, systems are operated a certain way, you don't deviate from that. My brain is conditioned by 30 years of dillidallying around in engine rooms. When one operates a boiler with a feed system, then that feed system has to run continuous and the operating time becomes the time it takes for the feed tank to be empty. A feedwater pump being switched off while a boiler is kept running is a no-no to me, and a feedwater pump being allowed to suck air against a pressurized boiler, even worse.
Call me silly, call me autistic (I am, so don't feel shy), but that was how it was going to be... A tank, a pump, boiler at constant level, and the operating time determined by the tank reaching low level.
I am, as you all have seen in the pics of the wick feed lubricator, a horribly poor metal sheet worker, so making a feedwater tank myself would not be very succesful.
Regner (at the timethe only supplier I was familiar with that could deliver in reasonable time, because in early August I was a total newbie in the world of model steam) only had a cylindirical 300 ml tank that would not fit in the boat, and a rectangular tank that would fit, but only held about 75 ml of water... So my autistic brain hit a snag: If the boiler has a steamable content of 180 ml, but a feedpump set-up would only be 70 ml of "consumable water", I would be going to LOOSE operating time.
Heck, I was fully aware that I could run the feedpump as long as the tank lasted, then continue emptying the boiler and I would gain maybe 6 or 7 minutes of operating time, but... To me, that would be a total turn-off. A bandaid, a non-solution. A patch. I could not envision deriving joy from that type of "solution".
I searched high and low in all kinds of non modelling related shops for suitable larger containers I could adapt, but no luck.
So I decided to make the feed tank out of plywood. Sounds silly, but... I normally build planes and such, I knew I could knock a tank out in mere hours, and to basically any shape I wanted. Waterproofing is easy: one or two coats of pore filler and sealing it up with the type of polyurethane laquer as used for hardwood flooring.
I ended up with a wedgeshaped tank, 12 cm long, 7 cm wide narrowing to 5 cm, and 5,5 cm in depth, theoretical almost 400 ml.
Open top with anti-sloshing baffles, practical tests showed it would safely hold 375 ml in actual running conditions...
https://www.modelbouwforum.nl/attachments/20230623_200420-1-jpg.544502/ (https://www.modelbouwforum.nl/attachments/20230623_200420-1-jpg.544502/)
So.... NOW we're talking... this brought the boat to about 25 minutes of operating time, 30 if I took it really slow...
By this time, I started realizing that feeding from a tank will introduce dissolved gasses in the boiler, and these non-condensable gasses will end up in the level glass eventually, but... the Microcosm boiler has its feedwater connection at the bottom of the level glass, so this immediately presented the problem that as soon as the feed is in operation, boiler level becomes hard to read.
This issue with dissolved gasses can be reduced significantly by keeping an eye on water quality, I might spend an episode on that later, but for now the problem was there and had to be dealt with.
What good is it to have a controllable pump, but no means to visually check the level?
I solved this by installing a blow-off valve in the top of the glass.
https://www.modelbouwforum.nl/attachments/20230930_101117-1-jpg.555012/ (https://www.modelbouwforum.nl/attachments/20230930_101117-1-jpg.555012/)
The discharge line of this valve ends up at the bottom of the feed tank. Initially I was a bit worried that this might lead to accidents with the steam pressure blowing out the contents of the feedwater tank, but practical tests showed this to be a non-issue: Even with only 1 cm of water in the feed tank, and the blow-off valve fully open at full boiler pressure (max 2 bar in my case) the heat absorption of the feedwater is so strong that steam does not even reach the surface of the water. It's 100% safe.
As it is right now, I fire up the boiler from cold with this valve open, during warm up the air escapes (with a funny "gloop gloop" sound) and as soon as steam is raised the sound changes to the percolating noise of a coffeemaker. Very convenient.
Enough about the level glass...
By now I had achieved an operating time of about 25 minutes before I had to come in to refill the feedwater tank, which due to the open construction could be done "on the fly" with the boat in the water. The gas tank allowed for about 50~55 minutes of operation (including the firing up from cold) on a charge of 60 grammes of propane/butane mix.
Although now absolutely acceptable, I still wasn't really satisfied with the fact that I had to come in for water while obviously the fuel quantity allowed for much longer operating time, and overthinking things, I also thought that feeding a boiler with cold water is not the most eficient way of feeding a boiler. But what good is it to save on fuel when you don't have the water to evaporate with it?
Hmmm.... How if...?
How if I would utilize the exhaust steam to pre-heat the boiler feedwater? It would improve the operation of the boiler (in more than just "lower fuel consumption" by the way), but it would ALSO produce condensate. Condensate that MIGHT be usable for return to the feedwater tank, thus extending operating time, right?
A quick calculation showed that the condensate generated by the pre-heating of the feedwater alone, would yield at best 15% of the water feedrate.
That's a simple calculation, water per gramme requires a certain amount of heat to raise temperature from ambient to 100 deg C, and condensing steam delivers a certain amount of heat per gramme of condensed steam, and that ratio is roughly 1:7
Since we're talking here about a feedrate in the order of magnitude of 10 ml/min, the heat dissipation for preheating the feedwater is approx 50 Watt.
and a condensate return of maye 1,5~2ml/min
Disapointingly low yield. Would it be worth it?
Then it struck me: the condenser/preheater would be a shell to which steam is supplied, with a coil running through it conducting the feedwater. But the shell on the outside has exposed surface, dissipating heat to the ambient air.
A quick google search on the subject of radiator heat transfer combined with the expected dimensions of the condenser, hinted at a radiated heat of approx 80 Watt, which would probably generate another 2~2,5 ml/min.
OK... now we're talking, because that would reduce feedwater consumption from roughly 10 ml/min to 6 ml/min, and a quick estimate it would reduce fuel consumption by about 10% as well... Meaning I should be able to extend times between water refill, and possibly reduce the filling charge of the gas tank to 50 grammes.
The condenser was made with a coil of 1 metre copper tube 3 mm OD, fitted in a piece of vacuum cleaner tube, capped with two discs of aluminium, held together by a threaded rod.
https://www.modelbouwforum.nl/attachments/20230929_194756-1-jpg.554978/ (https://www.modelbouwforum.nl/attachments/20230929_194756-1-jpg.554978/)
https://www.modelbouwforum.nl/attachments/20230929_200229-1-jpg.554979/ (https://www.modelbouwforum.nl/attachments/20230929_200229-1-jpg.554979/)
Since exhaust steam can contain traces of cylinder oil, a condensate cleaner was built into the feedwater tank.
https://www.modelbouwforum.nl/attachments/20230924_093948-1-jpg.554374/ (https://www.modelbouwforum.nl/attachments/20230924_093948-1-jpg.554374/)
https://www.modelbouwforum.nl/attachments/20230924_155120-1-jpg.554435/ (https://www.modelbouwforum.nl/attachments/20230924_155120-1-jpg.554435/)
https://www.modelbouwforum.nl/attachments/20230924_155126-1-jpg.554436/ (https://www.modelbouwforum.nl/attachments/20230924_155126-1-jpg.554436/)
https://www.modelbouwforum.nl/attachments/20230924_155131-1-jpg.554437/ (https://www.modelbouwforum.nl/attachments/20230924_155131-1-jpg.554437/)
The condensate cleaner consists of a compartment of approx 25 ml, with a dividing bulkhead that forces the condensate to pass underneath.
The large side of the division is where the condensate enters, and in this part, oil absorbing material is floating on the water.
To make absolutely sure, a single sheet of oil absorbing cloth is floating on the feedwater tank as well.
https://www.modelbouwforum.nl/attachments/20230925_110235-1-jpg.554563/ (https://www.modelbouwforum.nl/attachments/20230925_110235-1-jpg.554563/)
Condensate enters, possible oil traces are trapped in the absorbing material, water passes underneath the divider, and flows over into the feedwater tank.
The first test:
https://www.youtube.com/watch?v=rqYJdb_I7AM (https://www.youtube.com/watch?v=rqYJdb_I7AM)
This test showed that the single steam/condensate exhaust was a mistake, because the condensate ended up where it was intended, but the escaping steam caused unwanted condensation everywhere else in the boat.
WOW! First test at varying power settings (emulating normal use as good as possible) immediately resulted in an operating time of 50 minutes with some gas and water to spare...
NOW we're talking...
But I still had to solve the issue with steam all over the boat. First step: a separate exhaust.
https://www.modelbouwforum.nl/attachments/20230930_013649-1-jpg.554999/ (https://www.modelbouwforum.nl/attachments/20230930_013649-1-jpg.554999/)
This did not solve the problem, it relocated it, because yes, the steam vented out, but it also sprayed condensate drops everywhere, so the boat still got wet all over. So a moisture trap with drain back to the feedwater tank was fitted. I don't have a pic, only a video:
https://www.youtube.com/watch?v=YxztgtuN-ZI (https://www.youtube.com/watch?v=YxztgtuN-ZI)
and now that problem was solved as well.
The white "cap" on the condensate drain is an orifice, intended to allow condensate to pass but limit the escaping steam to a minimum.
It also serves to make the outflow of condensate a bit less abrupt, giving the filter more time to absorb any oil traces.
But... although I had clean condensate for about 30 minutes, then the condensate turned turbid and dirty, too dirty for the condensate cleaner to keep up... Damn, what happened?
I found out that the oil separator vessel as supplied with the machine, would be full after approx 30 minutes, and after that, oil would pass the separator and enter the condenser. I first tried to reduce condensation in the oil separator by thermally isolating it:
https://www.modelbouwforum.nl/attachments/20231003_230559-1-jpg.555625/ (https://www.modelbouwforum.nl/attachments/20231003_230559-1-jpg.555625/)
This did NOT make any measurable difference. So I had to figure out a way to remove this water "automatically".
I messed around a bit with designing a float valve, but the numbers are not there: in the dimensions availlable (max diameter 7 mm) and the materials and methods at hand, it turned out impossible to make a float with sufficient displacement to actually float...
If difficult and complicated solutions won't work, the only option is to go simple, and I solved this by simply fitting a 2 mm OD (1 mm ID) copper tube in the oil separator, all the way to the bottom.
https://www.modelbouwforum.nl/attachments/20231004_171543-1-jpg.555648/ (https://www.modelbouwforum.nl/attachments/20231004_171543-1-jpg.555648/)
https://www.youtube.com/watch?v=TUNN3FOJzQM&t=18s
(in the pic, the tube is still 3 mm OD, flattened at the end, as demonstration of principle only, the tube is now 2 mm OD, and the receptacle has been replaced with a stainless steel bottom part of a coco shaker)
This tube allows the very dirty crap that collects in the oil separator to discharge to a larger collecting reservoir. Now the oil separator stays dry inside, the condensate remains clean, and the condensate cleaner easily lasts 10 or more operating hours.
the receptacle for the crud from the oil separator suffices for about 2 hours.
Technically, this is what I have done to the installation.
I started with 10~15 minutes operating time, a waterconsumption of around 700~800 ml/hr and a fuelconsumption of 75 grammes per hour (average values, give or take, applying to average running conditions), and ended up with 50 minutes of operating time, about 400 ml of water per hour and 55 grammes of fuel per hour.
I grouped these posts by subject, but in reality everything went kriss-kross, all at the same time and in WAY more time than it took me to write these posts. I actually learned a LOT, despite having been involved in operatiing steam plants professionally, for many many years.
I freely admit that my "professional deformation" caused me to do things different than probably 99% of model steamers, and I am not sure if any of this is useful for other steam enthousiasts.
For me, the experimenting, the testing, the overthinking, the solving puzzles and the search for ways to achieve results with absolute minimum means, the "McGyvering" so to say, absolutely was worth it.
I ended up with an extremely userfriendly, easy to operate and reliable set-up despite the use of Micky Mouse methods and materials.
https://www.youtube.com/watch?v=3NY6Gr5_aiw (https://www.youtube.com/watch?v=3NY6Gr5_aiw)
A bit outside the scope of the subject of "modifications" but still maybe interesting for some, is the subject of "feedwater quality" and the experiences and observations I gathered in that respect while doing this project.
I might post about that as well.
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You can buy temperature sensors that measure internally. As you have discovered there is way too much lag in using an external temperature reading to determine pressure.
Clevedon sell a sensor separately as well as part of their Electronic Gas regulator Unit:
http://www.clevedonsteam.co.uk/products.html#thumb (http://www.clevedonsteam.co.uk/products.html#thumb)
As does Denes Designs:
https://www.denesdesign.co.uk/home (https://www.denesdesign.co.uk/home)
Oh, that certainly is an option.
But what can I say? A few months ago, when the burner control was the issue of the day, I was not aware of what could be had commerically and what not.
Nor was I looking.
My attitude towards this project, from the beginning, was more that of "what can be done with minimal means?" as opposed to "let's solve issues by spending money".
Please don't get me wrong, that is not meant derogatory in any way, towards anybody. Because in fact, I can afford to buy stuff, and there is nothing wrong with buying fancy stuff (I do that all the time for other hobbies) but it simply was not the starting point of this project. I wanted to see how far I would get on my own, with my (for this particular subject) limited skills and options. I bought what I HAD to buy (pressure sensor, feedpump, blow-off valve for level glass, gas regulating valve, and the Regner fitwork (cutting rings, capnuts etc).
I on purpose refrained from buying level control systems and pressure controllers and such. I wanted to see how far I could get with clever programming, and simple mods doable by anyone regardless of availlable tools and materials, regardless of skill levels.
But I have to comment on the lag: Actually, the measurement was much faster than I expected, and without issues fast enough to keep the pressure under control within very reasonable limits. The issue was not the lag, but the fact that external factors (mainly wind) affected the measurement,
In light wind conditions (<2Bft) Going downwind the boiler would stabilize on a different pressure compared to going against the wind, for example. Anything over 2 Bft, I had to switch to manual.
Under testing conditions in the bathtub (no wind) the temperature measurement simply functioned, no comments.
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On the Microcosm set-up there are a few things I really like.
-The hand operated valves work well, close off properly and do not leak through the glands.
-Ditto for the glands on the engine. There is a bit of cylinder oil passing the glands of the pistonrods and valve pushrods, but no water or steam, basically everything stays bone dry.
-The gas tank has a safe capacity of 60 grammes of gas, which allows for well over an hour of operation, provided the engine is optimized and feedwater allows.
-The engine is fairly strong, on a mere 1,5 bar working pressure it easily pulls a 60 mm fourbladed prop, the boiler is rated for 4 bar (safety valve setting) and my estimate is that on 3 bar it will have very little problems with a 75 mm prop.
-The engine, once broken in and optimized, runs extremely smooth and silent, with a very wide RPM range, relatively vibration free.
The things I did NOT like:
-The gas valve on the tank is very unsuitable for controlling the fire. A separate (remote controlled) valve basically is a must not because of safety but from a practical point of view.
-The oil separator is too small: it works more or less OK for the duration of one boiler filling, BUT... that is only if you empty the separator after warming through the engine, because the first start of a cold engine will fill the separator to at least 1/3rd if not 1/2 of its practical capacity.
In itself not bad, but totally worthless if the engine is fitted with a feedpump for extended operation. Emptying the separator with the system operational, requires removing a hot plug, and messing about with a large syringe drawing up very dirty water close to boiling point. Not the safest of operations. Then again on the plus side: WHEN empty, the separating function is excellent, no ifs or buts.
-Another thing I did not like was how the boiler is attached to the baseplate by non-adjustable tie-down straps. The fit is loose and the boiler can shift a bit in fore/aft direction.
-The fit of the steamdryer/superheater assembly in the fluegas tube is a bit loose as well, although this does not lead to any problems.
Nothing to do with the Microcosm, but...
As I mentioned earlier in the thread, I fitted a Regner feedwater pump.
This pump basically is a servo (a cheap one at that) with a crank instead of a conventional servo arm, and a plunger pump attached to it.
Nothing out of the ordinary.
What Regner did to the servo, is basically disconnect the mechanical link between output shaft and feedback potentiometer. This effectively turns the standard servo electronics into a crude form of ESC.
The issue is with the servo they selected: it is a fairly strong servo with metal gears, and one of the first things I noted was that the thing was pretty noisy, and the output shaft wobbled suspiciously under load. The picture on their webshop shows a Hitec Servo for this purpose, but in reality, what I received was equipped with a different brand. Cheaper.
After approximately 5 operating hours, the servo started to make funny noises and within 10 minutes it died. Damn it!
Fair is fair, had I sent it in, I would have received a new pump, because Regner takes service and customer satisfaction pretty seriously.
I reported the issue to them AFTER I had opened the thing myself, including pics, and they STILL said they would replace it for free.
but I was a bit limited in time (at that time I had to go back to sea wintin the next week) and I did not want to spend the last 10 days of my holiday without a functioning toy project. So I opened the servo to see what I could do.
Turned out the motor was dead, and well, that is something that can happen. I had no real issues with that.
What I absolutely did NOT like, was the fact that the servo was fitted with Nylon slide bearings of a standard ball bearing size.
This is the output shaft with the slide bearing in the position on the shaft that it has in assembled condition:
https://www.modelbouwforum.nl/attachments/20230704_085312-1-jpg.545486/
Does not look bad, but...
This is the shaft how it runs in that bearing:
https://www.modelbouwforum.nl/attachments/20230704_085325-1-jpg.545487/
The serrated part of the shaft, is where the bearing runs, in other words: there is basically a grater continuously running in an unlubricated plastic slide bearing.
Even if the motor had not broken down, this construction would not have been very durable.
What I also did not like was the fact that the crank did not have internal serration, it was just an undersized smooth bore forced onto the output shaft with no other means of attachment but the tight fit.
https://www.modelbouwforum.nl/attachments/20230704_092356-1-jpg.545490/
Now I can do what Regner did, and I had plenty servos laying around, so I took an old Futaba S3001 (no metal gears, BUT ballbearinged), opened it up and cut out the stroke limiter so the servo could turn continuously, and also removed the potentiometer-drive.
The original crank was not usable on the S3001, but a simple 1,5 mm hole drilled in a servodisc at the correct distance solved that.
Fit between mounting plate and servo is not optimal, but this set-up has not given me issues in now close to 30 or 35 runhours.
Dont get me wrong, the bottom line is still in the plus: The set-up as I have it now, is extremely easy to operate, runs as smooth as silk, has an excellent operating time and I had a blast "developing" this little chinese machine.
Underneath the shortcomings, a true little gem is hidden. And this gem can be uncovered without any significant machining skills or metal working equipment.
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Quite fascinating and very interesting, well done. One thing you may want to consider, if you haven't already, is to increase the prop diameter, pitch or blade number. In my experience steam engines like to turn over with fairly low revs for the best performance and duration. I have two steam models, Canopus 1899 - a Victorian battleship at about 35 pounds in weight and 53 inches long and Velox a 1904 early destroyer about 65 inches long but of course very narrow. (Both on U-tube).
Both use Cheddar Models Puffin boilers - Canopus the mk 1 with return flue. First sailings were very disappointing with only about 15 minutes sailing and slow speed. By degreed I ended up with much larger props with 4 blades and the speed doubled as did the duration to 30 mins which I'm happy with.
Simplistically I tend to think a boiler has only a certain number of bites of steam. If the engine rotates fast you suffer poor duration as you use the bites very fast. If the engine rotate slowly than the duration goes up and if the prop combination is right the speed increases as well. Canopus uses an original Puffin double acting oscillating unit and turns two 45mm 4 blade props.
Velox uses a mk 2 Puffin boiler with no return flue so volume wise takes about 40% more water. The engine is my own designed in line twin double acting oscillator which works well and I get about 25 mins max sailing, mostly because I tend to go at full speed so the bites of steam are used much faster.
Cheers and happy steaming!
Geoff
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So Bert says......."The gas valve on the tank is very unsuitable for controlling the fire. :o
Could I suggest Bert, that the gas tank valve offered here is literally an isolation valve for gas ....and has no compensating design as built for regulating steam to the engine >>:-(
Derek
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:D you could suggest that, and you would be completely correct... It's a stop valve (isolating valve) and I simply ran out of words, since English is not my first language.
But given that Microcosm offers the engine without burner/pressure controller and offers this as an option, it could be expected that the valve at least has some controlling properties.
At least that's what I expected, and that's why I mentioned it.
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Quite fascinating and very interesting, well done. One thing you may want to consider, if you haven't already, is to increase the prop diameter, pitch or blade number.
Yup... that's what I did indeed. The prop supplied with "Borkum" is a 55 mm fourbladed brass prop of less than optimal quality.
I replaced it with a 60 mm Raboesch #147 (fourbladed prop) whih has a much better efficiency.
RPM dropped (a bit) and speed at the very least remained the same or even improved a little bit.
The 60 mm is really the largest I can fit (clearance to the hull maybe 1~1,5 mm) but functions well and indeed I do have the distinct impression this also played a role in reducing steam consumption.
Unfortunately I had the condenser first and the prop after that, and I cannot disable the condenser so it was not possible for me to determine effect separately.
One thing I did notice was that with the original 55 mm prop, upon giving full ahead the engine went to peak RPM and that RPM did not seem to increase with the boat reaching "terminal velocity".
With the 60 mm Raboesch, I have the distinct impression that with increasing speed the rpm ever so slightly rises, which to me suggests prop, engine and hull are fairly matched, since this usually also is what happens in real-life propulsion installations.
For those that haven't peeked around on my channel, this is a recent outing on the pond (after appr six minutes the boat can be seen from the pond side)
https://www.youtube.com/watch?v=DO0wN5Nth-A
From 3:58 to appr 4:15 it can be observed that on giving full steam, RPM rises with boat speed, and sags during the full rudder turn (full steam kept) to rise again on the straight run.
From 9:05 till 9:28 is a full speed run.
Cheers and happy steaming!Geoff
Thanks, I most definitely will! Just home from a 55 min run on the pond, 350 ml of water and 48 grammes of gas through the funnel, the runhour counter ending at 44,9 runhours. :D
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The isolating valve should in theory be capable of some gas control but in practice it tends to be on or off (I have one in Velox) but that's exactly what I wanted as if I foul some debris in the pond I can turn the gas off so no damage to the model if it runs out of water.
In Canopus I don't have room for the valve so I use a much cruder system. Canopus also has a blowlamp burner so as an emergency measure I use a car windscreen washer motor to spray water onto the burner which puts it our every time with a nice puff of steam out the funnel so I know the burner is out. The downside is the model fills with gas but as there is no ignition source its just not a problem, besides better than watching the model burn!
In my experience if a boiler runs out of water, its not the end of the world as a single flame cannot generate enough heat to un silver solder that mass of copper, its just not possible. I checked with Cheddar Models years ago when this happened to me.
What will typically happen is that the lagging will charcoal and may eventually catch fire which can spread to the model and destroy it, particularly if the boiler is completely enclosed within the model. I speak from experience! If it does happen don't touch the boiler, let it cool down for about 5 hours and for gods sake don't be tempted to fill it with water otherwise you will scald your self as the water flashes into superheated steam.
Cheers
Geoff
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What will typically happen is that the lagging will charcoal and may eventually catch fire which can spread to the model and destroy it, particularly if the boiler is completely enclosed within the model. I speak from experience! If it does happen don't touch the boiler, let it cool down for about 5 hours and for gods sake don't be tempted to fill it with water otherwise you will scald your self as the water flashes into superheated steam.
Cheers
Geoff
:D the chapter "specific dangers and properties of steam" in the fleetmanual of my current company was literally written by me, as I was the only one back then with practical experience with steam (all other vessels up till then were fitted with Thermal oil as primary heating).
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Hello !
Interesting post Bruttus ! Thanks to share ! ok2
I love the fire extinguisher of Geoff ! Smart and very clever : also nice to watch it working.
I also agree 100% with what you say concerning flaring in a dry boiler. Nothing will go wrong but the lagging will suffer.
Below is what happens to me when my wife calls me on the phone , saying that she will be short ! I didn't dare to hang up ! %)
https://youtu.be/WywfGF144aY?si=KJzk_gqCxSwl605X (https://youtu.be/WywfGF144aY?si=KJzk_gqCxSwl605X)
It is already hard to silver solder a boiler properly , so a single Bu/Pro burner in it will get hot without damaging nothin.
Cheers !
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Hello !
Interesting post Bruttus ! Thanks to share ! ok2
Thanks for the compliment and you're welcome.
In doing all this, I learned a bit about water and how to treat it. I used to "know everything there is to know" about boiler and cooling water testing and treatment, but haven't used that in a long time because the last 10 years I've not worked with steam anymore. However, that is not what I mean.
Model steam has different requirements, and I am fully aware that for most people, most model installations and most situations, boilerwater treatment is rather irrelevant.
Yet, since the last two months or so (two months at home, there is seatime inbetween) I have been pretty much steaming at least 1 hour per day on average, so I did do some observations that MIGHT be of interest for some of you.
I'll probably post something about that as well.
I love the fire extinguisher of Geoff ! Smart and very clever : also nice to watch it working.I also agree 100% with what you say concerning flaring in a dry boiler. Nothing will go wrong but the lagging will suffer.Below is what happens to me when my wife calls me on the phone , saying that she will be short ! I didn't dare to hang up ! %) https://youtu.be/WywfGF144aY?si=KJzk_gqCxSwl605X (https://youtu.be/WywfGF144aY?si=KJzk_gqCxSwl605X)It is already hard to silver solder a boiler properly , so a single Bu/Pro burner in it will get hot without damaging nothin.Cheers !
It is good to know that these small boilers do not damage all that easily, but I can't help it, professional deformation causes the back of my mind to start screaming bloody murder when water level even only gets close to the top of the flue tube. :D :D :D
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Controversial subject...
Steel boilers need treated water. Dissolved oxygen is harmful, pH needs to be a fair bit over 8 (from memory way back when I still operated large boilers, pH of boiler water was kept well above 9, pH of condensate "at least above 8", CL "as low as possible" but according to Nalfleet and Unitor 300 ppm was allowable, and a surplus of Sulphite, an oxygen scavenger, but I don't remember what the recommended value was).
Brass and Copper basically are not too picky about the water quality, as far as I know it should neither be too acidic nor to alkaline, and basically containing as little as possible scale forming dissolved solids (TDS), because you don't want to have to treat the boiler with citric acid.
Some model steamers and manufacturers of model steam recommend adding about 5% tapwater to demi water in order to get a slightly alkaline feedwater. If I understand the reasoning, this is because demiwater is NOT the same as destilled water: Demiwater still contains the same amount of ions as the water it was produced from contained, just the scale forming ones have been replaced with non-scale forming ones. These ions can possibly react with the zinc in brass, and that is undesirable.
Destilled water contains barely any ions, period, which should (in theory) leave the zinc alone. Metals as such do not dissolve in water, they need to first have reacted with another element to form a compound like a salt or other compound soluable in water.
Mind you, this is a theory I have heard, I am NOT a chemist. But if this theory is correct, distilled water should be "safer" (less harmful to brass) than demineralized water.
Then again, there are LOTS of different alloys that can be called brass, and some are very resistant to dezincing, others aren't.
To be honest, I would not really know, because my professional experience is limited to steel boilers. I did read some things about dezincing brass fittings (a study performed in commission for one of our water grids) but that study only mentioned the effects of Chlorides and CO2, which makes me conclude that distilled water does not affect brass too much. Demi water might be another thing, I really can't tell, I could not find any clear or conclusive info on that.
According that study, CL increased dezincing, CO2 reduced it. To the best of my knowledge, CO2 dissolved in water makes the water acidic, so that confused me a little bit.
PLEASE correct me if I'm wrong, because I could not really find much on the subject, and asking around with a few dutch model steamers also did not really yield clear answers.
I did some testing with the TDS numbers.
I destill my own feedwater (simple commercially availlable destiller, if you do it properly it is near free because that thing heats my living room pretty good, so I can switch off the central heating for several hours :D).
Our local tapwater is about 200 ppm TDS, my destiller manages between 1 and 3 ppm. A cup of tapwater mixed with 5L of destilled water results in approx 20 ppm.
Running the boiler for 1 hour on that feedwater, the boiler water rises to 60 ppm, roughly. My TDS meter turns from green to red at 50 ppm, so I assume 50 ppm is some sort of treshold value for deposits or something.
Running the boiler on straight destillate, it takes about 4 hours before the boiler reaches 30 ppm,and about 5 or 7 hours to reach the redline of 50.
So I decided to run straight destillate and refresh the boiler every 4 hours, because that is convenient: I don't need a calculator to see whether a number is divisible by 4 so that is easy to keep track of, no logbook or such needed.
Now that is all not so very important, I mean, everybody has his own ways to deal with the water, and I guess most people just buy a bottle of demi or destilled, and never give it a second thought.
But.... does it make a difference?
I can only say that Yup, it does... After spending (no joke) about 20 hours watching the levelglass in the last 2 or 3 weeks, keeping track of TDS numbers, the difference between a boiler filled with destilled water, versus a boiler filled with, say, water containing 50 ppm TDS is clearly visible in how the water behaves in the level glass. Lots more movement in the glass during constant steam demand, and the water level responds much stronger to changes in steam demand as well. A "clean" boiler, going from minimum RPM to full, the level rises by maybe 5 mm. Visible but not remarkable, but at 50 ppm, that level change can easily be 15~20 mm, and water carry-over in the steamline is not unthinkable.
Level glass becomes increasingly harder to read.
Is it important? Most probably, not at all. Not when steaming is done occasionally and the boiler always emptied after use and refilled with fresh water before use.
Right now, I run the plant too often to bother with emptying it every time after use.
But in case anyone wondered, no need to wonder anymore.
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I am fully aware that I have taken some of the things mentioned, quite a bit further than anybody in his right mind would.
I mean, who would ever bother to check boiler water properties? Who would take the trouble of pre-heating boiler feedwater, or attempting to recover condensate?
Does it have any useful purpose at all?
I guess that depends on what one expects from it all.
I can't help it, I'm an engineer and I run basically everything from tiny model airplane engines to this model steam plant, as optimal as possible, and to be honest, I think when all separate issues come together and all is added up it makes a significant difference.
-The lubrication set-up with the wickfeed makes for a hassle free operation with good wear behaviour: I am at 46 hours of runtime now, realistically, that is what most people need several seasons for to reach, and for this class of engine (brass, not very precisely made) maybe even close to end of useful life. Yet, the engine runs like new, heck, better than new because straight from the box it ran not nearly as smooth as it does right now.
-The pressure control with proportional burner control makes for as constant as possible operating conditions. This in itself does not contribute all that much to efficiency, BUT it makes for constant numbers, making it easier to detect deviations and anomalies. It also makes for a more stable operation of the displacement oiler, which saves oil but also improves how the engine runs.
-Keeping an eye on waterquality helps the workings of the level glass, making it easier to monitor feedrate and in general reducing the risks of low or high boiler levels. Whether an occasional low water level will lead to damage or not, running it dry surely is NOT going to prolong its life.
These more stable running conditions make it possible to prolong the operating time without supervision. I mean, there is no point in arranging for a 50 minute feedwatersupply if you still need to come in every 5 or 10 minutes to check boiler level, lubrication or whatever, right?
So yes... Although it started out as a silly experiment, a project born from wild ideas and intended to just in general waste my free time with, in hindsight I think I would repeat it for a possible next steamer project. Most definitely the condensate reclaiming. Because the result is an easy to operate boat with a very accpetable operating duration, requiring very little attention in practical use. I'd say it was also worth it from the practical POV.
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I for one am very appreciative of your detailed engineering take on this as its a fascinating subject with lots of myths unintentionally propagated. Personally I'm a great favour of KISS but I really do appreciate those who take it all a step further. For me reliability is key, I expect my models to work well every time I use them without breakdown.
I'm also aware of the expression, use it or lose it! I hadn't sailed Canopus for about 5/6 years and she was very spiteful because of it but we are all good now.
I had a number of problems - the burner kept going out after about ten minutes. Odd because Canopus was always 100% reliable. There were two causes for this. The first being I had left some gas in the gas tank and it had deteriorated and produced a rust type sludge which from time to time blocked the jet. No idea why this should be but it happened. I also felt there was more steam blow-by from the engine but it was subjective so I improved the bulkhead between the boiler and the engine as I felt spare steam may be working its way back to the burner and putting it out. It worked but not 100% of the time and the duration was down from 30 mins to about 20 mins, also the speed seemed slower but that was subjective. I also installed a small PC fan to provide positive draft for the burner. I'm not sure if that was really necessary but it eliminated one further question so I'll keep it. It worked for years without it though!
In the end the "O" ring piston rings were found to have gone hard due to lack of use permitting more blow-by and increased steam consumption. In the end I replaced them with red silicon ones and instantly everything was restored to normal, speed up, duration up and everything good.
It will teach me to ignore the lady for too long - you know what they can be like when they don't get enough attention - lesson learned!! :-)
Do please keep up the technical side of things and happy steaming!
Cheers
Geoff
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Canopus
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I for one am very appreciative of your detailed engineering take on this as its a fascinating subject with lots of myths unintentionally propagated. Personally I'm a great favour of KISS but I really do appreciate those who take it all a step further. For me reliability is key, I expect my models to work well every time I use them without breakdown.
Thanks for the kind words. I hope to at least trigger people into thinking outside the box, because even with very modest and simple means, it turns out one CAN polish a 'unit of fecal matter'. The Mythbusters allready proved that in the literal sense, but it also is possible in the figurative sense.
I think you would be surprised how "simple" my set-up is.
Virtually everyone here uses a form of RC shutdown of the burner. I use that valve to also control steam pressure. A lot can go wrong with the diaphragms of analog burner controllers, I don't use that=>simplicity. There is, beside the pressure sensor no additional electronics in the boat.
Virtually everybody that uses a feedpump, uses an engine driven feedpump, with a remote controlled bypass valve and associated piping.
I use an electric feedpump, simple one-way piping from feedwatertank via preheater to boiler.
SOME people use electronic forms of level control. I don't.
Despite that, true, anything added to the base installation as delivered by Jin, can be seen as needless complication. But I like to think that the machine perhaps works "well" straight from the box, but functions "better" with the add-ons. And with "better" I mean most specifically smoother, less wear, more consistency. Ease of operation is a bonus IF (big if) that can be achieved...
So far aside from the faillure of the original drive of the feedpump (QC issue with Regner, I guess) the boat has proven to be extremely reliable with that faillure as the only one in now 46,5 running hours.
Just to give an impression: this is how easy the boat is brought into operation.
Previous to the video, the feedwater tank and gas tank were filled, and the burner ignited. Those proceedings are rather self-explanatory.
If the dutch language is an issue, switch on subtitles, then go to settings and change language to english.
https://www.youtube.com/watch?v=3NY6Gr5_aiw
In all fairness, nowadays I cast off the moment the engine is turning over, because there really is no need to wait for the condensor to start functioning. It is enough to keep power a bit down untli I see the steam coming from the exhaust.
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Canopus
Beautiful!
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I am sure there are quite a few Moddlers watching on with great interest Bert O0 ....
In particular, I await your discussions on the separating of engine condensate [removal of the oil] & reuse of the clean water......and further the preheating of the feed water
Do you not find the groaning of the Regner feed pump >>:-( a little off-putting?
[I haven't quite figured out the Female voice in your Videos offering achievement/comments at certain points {-) ...is She the voice element as part of the programmed Tx?]
Derek
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I am sure there are quite a few Moddlers watching on with great interest Bert O0 ....
To that I can only say: My crystall ball is back to the manufacturer for its yearly overhaul and tune-up, so currently, I cannot guess what you guys want to know.
But I will answer any and all questions.
Also: None of what I write should be considered as the one and only truth, please comment whenever I post something silly or incorrect.
In particular, I await your discussions on the separating of engine condensate [removal of the oil] & reuse of the clean water......and further the preheating of the feed water
Like this one, for example, An aimed question, I can comment on.
From what I have seen, and with the oil I use (I do not have a brandname, I picked it up from a local historical steampowered tugboat, it is what real life triple expansion machines use) the dirt virtually completely concentrates in the first condensate/crud after the engine. The stuff I collect from the oil separator is mainly water with a minute bit of oil on top (order of magnitude of 98~99% water, 1~2% oil) but that oil is strongly emulsified and does not separate whatever I do (I have tried, I have stored that collected crud for 3 months and saw zero separation) The amount of that crud varies with outside temperature, I think it is the steam that condenses IN the engine, and gets mechanically mixed with the oil. In summer season, about 60 ml per hour, currently closer to 75. So we're talking about a loss of non-recyclable water of roughly 10% of the total boiler feed. A bit less in summer, a bit more in winter.
The only thing that can be done with this crud, is to discard it.
The oil separator collects that and whatever steam leaves the oil separator, is basically clean. I do not even dare put a number on it, but it is closer to ppm range than to percentage or even promille range.
So we have a potential reclaim of 90%, give or take. This steam is routed through a condenser/preheater, where part of the steam condenses, the remainder is vented to atmosphere.
This condensate is led through a small filter compartment containing about 60 cm2 (6 strips 5 x 2 cm, stacked vertically like bookson a bookshelf) of oil absorbing cloth, as is used cleaning up marine oil spills and such. This is really weird material, it does not absorb water, it floats on water, and shows a very strong affinity to oil. It is commercially availlable for about €0,75 per sheet of 50 x 40 cm (but unfortunately only in boxes of 100 sheets minimum), and one sheet would typically last me for at least 40 hours of steaming or so. Initially I had to replace everything every hour, but that was before I fitted the oil separator with an auto-drain. After that, it really is no problem AT ALL... The water is clean and stays clean and the filterstrips show a very mild smear of discoloration after 10 hours or so.
The compartment is about 25 cm3 in volume and has a syphon: Water enters the filter compartment, passes the filterstrips, then has to pass UNDER a divider bulkhead that retains any floating oil not yet bsorbed by the filter. From under the divider the now clean water flows upwards and via a spillway into the feedwater tank.
Just for safety (the engine could theoretically fling oil droplets around) a sheet of that oil absorbing cloth covers the entire surface of the feedwatertank, but so far I have not yet seen the need to replace that.
And that's it, basically. Make sure the oil separator works properly by ensuring no liquid build up, and the condensate will be reusable with even the slightest bit of filtering. Not critical at all. No fussing with the passing time of the water in that filter compartiment (which in my case currently is approx 5 minutes by the way), because the condensate from the condenser is basically clean to begin with.
The preheating of the feedwater, there is not too much to tell about that. In reply #9 I showed how I built the condenser: It's a coil made out of 1 metre copper tube (3 mm OD) wound around a core of about 2 cm diameter (core removed after winding, of course, duh...). That coil is placed into a tube of about 3 cm diameter and about 10 cm length, and capped off with Aluminium discs. The feedwater is passed through the coil, the clean exhaust steam is passed through the condenserbody, the steam surrounds the coil and heats it. Condensate is drained off, remaining steam is vented to atmosphere. That basically is all there is to it. No controls, no automation, it just is what it is. The feedwater temperature is very constant. I do not know the exact temperature because the probe is tied to the outside of the feedwater line and then wound in cotton cord for isolation. Reading is around 71 degrees plus or minus 1 and steady regardless of load. Experience with these probes and isolation (I used the same method of measuring for pressure control, that's how I know) suggests that the actual feedwater temperature is around 85~90 degrees, but I have no way of knowing that for sure... But it basically HAS to be, because you cannot reach much higher temperatures using atmospheric steam, and although the inlet temperature at the heater coil rises by about 15 degrees throughout the run (feedwater tank warms up due to the inflow of hot condensate) the outlet of the heater remains constant, meaning it reaches end temperature achievable with atmospheric steam.
With only a feedwater preheater, the reclamation is practically limited to about 35~40% of total boiler feed, approximately. More would require additional measures. There are two or three possibilities to increase that to "everything there is to reclaim" but these options each have their own set of issues. I have only considered them in the form of a thought experiment ("mental simulation") only, and based on that rejected them all.
The easiest way is to install a pipe of suitable diameter underneath the boat, a bit like a bilge cooler. Upside is unlimited cooling capacity, downside is that it requires the feedwater preheater to be sealed up because it becomes "pressurized", and it requires this pressure to push the collected condensate back up into the boat. This backpressure can be unpredictable and affect the engine's performance.
It requires two hull penetrations, and at least one of them is subject to high temperatures, which also can cause issues endangering watertightness of the boat.
The most technically neat solution is to enlarge the condenser and install a 2nd coil through which outboard water is pumped. This requires a pumped volume of at least 6 times the boiler feed. Requires a pump (power) and a weedfilter. In my case, the required dimensions simply would become unmanageable.
The technically simplest way is to fit cooling fins on the condenser shell to increase heat dissipation to outside, but this requires eigher ventilation or an open boat, and in case of the latter, is downright ugly to look at.
All of them would allow for a MUCH smaller feedwater tank, which would mitigate the increase in dimensions of the condenser a bit.
For example, I run a feedwater supply of 375 ml right now which allows me to run 50~55 minutes. Maximizing water recycling would allow for a feedwater tank of only 100 ml for the same duration.
Do you not find the groaning of the Regner feed pump >>:-( a little off-putting?
Absolutely! But... the really weird thing is, that noise really is loud and annoying on the testbench or in the bathtub.... but as soon as the boat is 2 metres away from the dock, it is literally inaudible. I don't know how that works, but the first weeks I had that pump in the boat, I continuously brought the boat in to check if it was still running, I had to literally visually check, because I could not tell. And mind you, I actually DO have that "engineers ear", picking up the subtlests of sounds that shouldn't be there, and immediately noticing if a subtle sound that should be there is missing.
If you don't believe, check my vids if you can hear the pump running, for example this one:
https://www.youtube.com/watch?v=jqthLIf8VR4
The camera's mic is sensitive enough to pick up traffick 200 metres away through a forrested area, it picks up birds whistling at 50 metres, but around 1:40 the boat is less than a metre away and that's where you can hear the pump VERY faintly...
I have no clue how that works acoustically, but it is a fact, that in practical use the pump is inaudible.
[I haven't quite figured out the Female voice in your Videos offering achievement/comments at certain points {-) ...is She the voice element as part of the programmed Tx?]Derek
Yup... That thing can basically do anything I want it to do, including calling out telemetry values, but for testing purposes, I told it to give warnings for "cruise", "normal" and "landing" throttle valve settings so it would be easier to do repeatable tests: It is very hard to determine an improvement in operating time if you are not running the same speed between tests.
That lady indeed is annoying, I have since replaced those comments with beeps as they have served their purpose (basically, done testing), not nearly as annoying when actually on the pond.
What is left, is a warning to come in when the boiler pressure drops below 1 bar when the burner is at full. That tells me that either the fire has extinguished, OR the fuel is near finished. I'llprobably also will program an alarm for low and high feedwater temperature, as those are symptoms of failing pump or leaky valves respectively.
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As you may be aware on real ships of the 1890's to 1906 they typically used triple expansion engines and I they would also look to condense exhaust steam and re-use the water. I read somewhere they have settlement tanks, literally an open topped bath. Because oil floats on the surface they would physically scrape it off and then re-use the clean water. One of the benefits of using turbines was that the oil and water did not mix (okay there was a little bit because of bearings etc) but the condensate was much cleaner and therefore easier to re-use.
In real ships the condensers actually condensed the exhaust steam so fast they caused a partial vacuum so there was a further pressure differential between the steam pressure and the atmosphere which gave them an improvement in fuel efficiency in the region of 5% to 10%. Ships can actually sail a little faster in cold water because their engines will develop a little more power because the condensers work better. In model terms the effect is negligible and we do it to avoid contamination of the lake and get clean steam to come out of the funnels.
I have seen lots of people preheat their boiler feed water but in general do not think it makes a lot of difference at our scale because it takes relatively little energy to heat water to 100 C particularly given the small drops we are pumping into the boiler but something like 4 times the energy to change it into steam because its changing state - liquid to gas. Still its quite fascinating to see this and that's all part of the fun of the hobby, we do it for fun as much as actually sailing.
On Canopus and my other ship Velox I site the oil separator/condenser next to the gas tank so they are actually just touching. The waste heat then acts to gently warm the gas tank which is a good hand warm at the end of a run irrespective of the weather. This keeps the gas pressure from dropping. Similar to the above the gas is changing from liquid to a gas and needs energy to do this so its sucks the heat out of the gas tank and the surrounding air which is why the gas tank can feel cold.
Cheers
Geoff
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As you may be aware on real ships of the 1890's to 1906 they typically used triple expansion engines and I they would also look to condense exhaust steam and re-use the water. I read somewhere they have settlement tanks, literally an open topped bath. Because oil floats on the surface they would physically scrape it off and then re-use the clean water. One of the benefits of using turbines was that the oil and water did not mix (okay there was a little bit because of bearings etc) but the condensate was much cleaner and therefore easier to re-use.
In real ships the condensers actually condensed the exhaust steam so fast they caused a partial vacuum so there was a further pressure differential between the steam pressure and the atmosphere which gave them an improvement in fuel efficiency in the region of 5% to 10%. Ships can actually sail a little faster in cold water because their engines will develop a little more power because the condensers work better. In model terms the effect is negligible and we do it to avoid contamination of the lake and get clean steam to come out of the funnels.
I have worked with steam for about 15 years, and although never with piston engines, I have actually worked with steam turbines.
Just a few corrections: Those oil separator systems usually are what they call cascade tanks, a tank divided in compartments by a series of over and under bulkheads: Water passes under one bulkheas, over the next, under the one after that, etc etc.
They are rarely open top, not even in the old days, for reason of oxygen pick up and accidental pollution risks (a burst oil pipe somewhere in the engine room, would cause severe problems).
In factories and poweplants and such, they were more commonly open topped.
In each compartment the floating oil is absorbed by either Loofah Sponges or the same oil absorbent cloth I use. These sponges or cloths take some attention, and proper adjustment of the oil dosage plays a HUGE role in efficient operation here. In heating plants or turbine plants, usually a single cascade is enough, but for reciprocating, usually the cascade is 5 or more compartments.
The vacuum in condensers is actually NOT created by the rapid condensation of steam, but by the removal of "non condensables" (air). In reciprocating engine installations this was done by an engine driven "wet air pump", in turbine installations the vacuum was created by a cascade of 3 or 4 steam driven eductors.
Normally, in order to be able to start up a turbine steam installation, the vacuum has to be created first, but of course this is not possible in reciprocating installations, because no running engine=no operating wet air pump.
I have never seen bearing oil in the return from turbines, since usually the bearings are outside of the steamcircuit and contact between bearings and steam is impossible.
I have seen lots of people preheat their boiler feed water but in general do not think it makes a lot of difference at our scale because it takes relatively little energy to heat water to 100 C particularly given the small drops we are pumping into the boiler but something like 4 times the energy to change it into steam because its changing state - liquid to gas. Still its quite fascinating to see this and that's all part of the fun of the hobby, we do it for fun as much as actually sailing.
People don't pay attention then... It actually DOES make quite a bit of difference. There is about 1~1,5 minute in time, from the moment I open the main steam valve and get the engine moving, until the preheater starts to function. By that time I usually have the burner on auto, and steam throttle at 50%.
The moment hot water starts entering the boiler instead of cold, is very clearly visible in the burner reducing fire. It also is very clearly noticable in the burners ability to maintain pressure in high demand situations for longer with less fire.
But that is not the only issue: whichever way you turn it, the cold feedwater is NOT heated by the burner. It is heated by the surrounding water. This means that in a part of the boiler, the water stops boiling because of the cold inflow. Since the steam has to be generated somehow anyhow, this means the boiling process in the other parts of the boiler has to become more violent, and THIS is fairly visible in the behaviour of the level glass.
Ideally you want an as "quiet" as possible water surface, because that reduces water carryover and improves efficiency.
The difference I have observed in fuel consumption due to preheating, are in the order of magnitude of 15%. I really don't care about the fuel savings (I have to blow off unused gas before refilling anyway for other reasons, and the gas in not all that expensive to begin with) but the steadier operation, less violent boiling, reduced water carryover and thus more consistent cylinder lubrication all work towards a longer engine life, more consistent operation, and it does not cost me anything except for the one time investment in making a proper preheater (which cost me less than €20,- and about 1,5 hour to build).
I fully admit, that the differences, especially if looking at each item individually, are not all that big. Then again, they basically come for free or at worst a one time investment rather than a continuous effort, and all combined, they DO make a significant difference.
I went from max 15 minutes operating time on a sedate pace, a water consumption of close to 900 ml per hour, a gas consumption of about 65 grammes per hour, cylinder oil consumption of about 4 ml/hr, machine oil consumption of anywhere between 5 and 10 ml hr, and "ages" of cleaning between runs,
to 50 minutes of operating time at a lively pace, approx 350 ml of water per hour, 55 grammes of gas per hour, less than 1 ml of cylinder oil per hour, less than 1 ml of machine oil per hour, and the clean-up after use is reduced to about 5~10 minutes.
Say what you will, but to me those are very real differences: I know myself, and this boat would rather quickly have become a shelf queen without the mods, simply because one hour cleaning after 2 or 3 15-minute runs is not my thing,
And as you said yourself, if you don't use it you'll lose it...
On Canopus and my other ship Velox I site the oil separator/condenser next to the gas tank so they are actually just touching. The waste heat then acts to gently warm the gas tank which is a good hand warm at the end of a run irrespective of the weather. This keeps the gas pressure from dropping. Similar to the above the gas is changing from liquid to a gas and needs energy to do this so its sucks the heat out of the gas tank and the surrounding air which is why the gas tank can feel cold.CheersGeoff
This is the only thing I have been breaking my head over so far: There is PLENTY of waste heat in the boat, but I can't yet figure out how to transport that heat to the gas tank without creating an undesirable side-effect. I have been thinking about using "heat pipes" but that will get very ugly.
Rerouting the exhaust steam line will create issues with unfavourable condensate and backpressure.
Right now, I am thinking that probably the easiest will be to Epoxy a 5W resistor to the tank, and heat the tank electrically (5W is approximately the heat needed to evaporate gas at the rate of consumption). Not sure if or how I will solve that, but at least it will give me the possibility to somehow "control" that heating via telemetry. I still have one unused temperature channel that I can use to switch that heating based on the fuel line temperature.
But I don't particularly like that "solution" when there is literally around 200W of unused waste heat availlable.
Oh well, you can't win them all...
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Remember that urge for "consistency"?
I found an old HobbyKing combo of regulator, switch and voltage display all in one, and decided to install a 2S 2200 mAh LiPo. That way I have a constant voltage for the feedpump.
with the NiMH there is a voltage drop of about 15% during discharge, meaning the feedpump will run slower at the end of a battery charge.
And since that LiPo contains 16 Wh as opposed to the NiMH only 9,5, suddenly there is a bit of capacity to spare to add electric heating to the fuel tank.
5W should do it.
So here's the battery
https://www.modelbouwforum.nl/attachments/20231019_230739-1-jpg.557388/
Here's the switch
https://www.modelbouwforum.nl/attachments/20231019_230804-1-jpg.557389/
and I integrated a temperature sensor (for start/stop of the fuel cell heating) in the cradle of the fuel tank
https://www.modelbouwforum.nl/attachments/20231019_230659-1-jpg.557390/
The switch for that, the sensors, connectors etc, I still had lying around, all I need is one or two resistors that I can epoxy to the fuel cell.
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Thanks Bert....I read & reread post # 28 a few times with great interest
[I am familiar with ‘Oil-Sorb’ sheeting [we installed it {40 years ago} under the internal ship mounted travelling cranes of the BHP Iron Duke & Iron Monarch to eliminate drops of hydraulic oil landing on the 20 tonne HRC’s loaded for between Kembla & Westernport] - This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering
I ‘inbuilt an issue’ when installing a Microcosm P3 piston water pump, with eccentric driven vertical down piston shaft, from my Saito Y2DR horizontal steam engine …….the result was a migration of lubrication oil down the shaft and pooled around the shaft & into the waterside of the system, despite the integrity of the pumps piston seal
So my issue was oil in the water pressure side, and so without any form of pressure filter …….
Derek
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Thanks Bert....I read & reread post # 28 a few times with great interest
[I am familiar with ‘Oil-Sorb’ sheeting [we installed it {40 years ago} under the internal ship mounted travelling cranes of the BHP Iron Duke & Iron Monarch to eliminate drops of hydraulic oil landing on the 20 tonne HRC’s loaded for between Kembla & Westernport] - This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering
I have no idea if "Oil Sorb" is the same stuff that I use. I don't think that 0,75 Euro per season (give or take) is cost prohibitive, but having to buy a box of 100 sheets, yeah, I can imagine that that is not the most ideal way.
But there are easier ways to aquire, like asking around in local car workshops, communal accident response teams, fire brigades, that kind of thing, to see if you can get a few sheets.
Worldwide shipping is a bit tricky, but locally I would have very little issues purchasing a box of 100 sheets and distributing it among fellow model steamers at costprice. Maybe local clubs can do something like that? Many RC plane clubs purchase their glowfuel in a similar way.
I ‘inbuilt an issue’ when installing a Microcosm P3 piston water pump, with eccentric driven vertical down piston shaft, from my Saito Y2DR horizontal steam engine …….the result was a migration of lubrication oil down the shaft and pooled around the shaft & into the waterside of the system, despite the integrity of the pumps piston sealSo my issue was oil in the water pressure side, and so without any form of pressure filter …….Derek
oh, dang, that's a nasty one, but at least be happy your steamplant is a law-abiding steamplant, it conforms to the law of unintended consequences.
There's not much you can do about that specific issue, other than relocating the pump to an oil free spot: Viscosity of oil combined with the wetting properties of oil towards metal will absolutely drag oil against the working pressure into the waterside. Nothing can be done about that.
But in all honesty and fairness, I would have overlooked that issue too... Totally! It is one of those things you don't initially think about and in hindsight slap yourself for not having caught it before executing...
What you can do is feed the water through some sort of inverted "displacement oiler" of sorts, where water velocity is very low, allowing the oil to rise to the top and remain in the separator. Maybe that will have some effect. That oil is not emulsified, so it most likely will settle out fairly well. The separator should have about the volume corresponding to 5 times the flowrate per minute, allowing for a settling time of 5 minutes.
Only other option is relocating the pump, but I guess that's not really an option?
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Remember that urge for "consistency"?
I found an old HobbyKing combo of regulator, switch and voltage display all in one, and decided to install a 2S 2200 mAh LiPo. That way I have a constant voltage for the feedpump.
with the NiMH there is a voltage drop of about 15% during discharge, meaning the feedpump will run slower at the end of a battery charge.
And since that LiPo contains 16 Wh as opposed to the NiMH only 9,5, suddenly there is a bit of capacity to spare to add electric heating to the fuel tank.
5W should do it.
So here's the battery
https://www.modelbouwforum.nl/attachments/20231019_230739-1-jpg.557388/ (https://www.modelbouwforum.nl/attachments/20231019_230739-1-jpg.557388/)
Here's the switch
https://www.modelbouwforum.nl/attachments/20231019_230804-1-jpg.557389/ (https://www.modelbouwforum.nl/attachments/20231019_230804-1-jpg.557389/)
and I integrated a temperature sensor (for start/stop of the fuel cell heating) in the cradle of the fuel tank
https://www.modelbouwforum.nl/attachments/20231019_230659-1-jpg.557390/ (https://www.modelbouwforum.nl/attachments/20231019_230659-1-jpg.557390/)
The switch for that, the sensors, connectors etc, I still had lying around, all I need is one or two resistors that I can epoxy to the fuel cell.
Meanwhile the switch and telemetry-function to activate that switch have been insalled/progged, waiting is for a few "cement resistors" to heat the gastank.
Curious what it will bring...
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This ‘Oil-Sorb’ material is cost prohibitive for model steam engineering
I looked into this, and although Oil-Sorb appears to be a brand name, as far as I can see it is the same stuff I use.
Unless local regulations or taxes or whatever have an influence on price, it really should be relatively affordable (at the rate I am using it, less than 1 Euro's worth per month, and I am running an extreme amount of hours per month).
Make sure you use the white version, NOT the grey version. The white version absorbs only oil, the grey version absorbs oil and water, meaning it has reduced effect when becoming waterlogged.
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Well, would not break the Bank, but better if another 99 Modelers would need a sheet {-) .....yes the white version [adsorbs petrochemicals 'oil' only]
https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjSsZz1rIWCAxU12kwCHcpmCfkYABAMGgJ0bQ&gclid=CjwKCAjwysipBhBXEiwApJOcuw9DjsMMuYbSGtFvyJxc9NmSsE-viN-RTQYk7kpZGwKulVzQyk9PKBoCGhYQAvD_BwE&ohost=www.google.com&cid=CAESV-D2xMtXYLFtldxxPT5qrXx4sOIuNZGGkDYQw6WjJeS7Vjt2Yk-cTM7wplq8isPxTQLXg5mGIOjyRdKUVqab3P43fCjF_AB21tq8CxXUP-_mHV9_TjtMog&sig=AOD64_2ofYquLe6EHRuXd7CGnXPNG7hpZQ&ctype=5&q=&ved=2ahUKEwi02pb1rIWCAxULhVYBHQ_xAW0Q9aACKAB6BAgDEFM&adurl=
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Well, would not break the Bank, but better if another 99 Modelers would need a sheet {-) .....yes the white version [adsorbs petrochemicals 'oil' only]
https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjSsZz1rIWCAxU12kwCHcpmCfkYABAMGgJ0bQ&gclid=CjwKCAjwysipBhBXEiwApJOcuw9DjsMMuYbSGtFvyJxc9NmSsE-viN-RTQYk7kpZGwKulVzQyk9PKBoCGhYQAvD_BwE&ohost=www.google.com&cid=CAESV-D2xMtXYLFtldxxPT5qrXx4sOIuNZGGkDYQw6WjJeS7Vjt2Yk-cTM7wplq8isPxTQLXg5mGIOjyRdKUVqab3P43fCjF_AB21tq8CxXUP-_mHV9_TjtMog&sig=AOD64_2ofYquLe6EHRuXd7CGnXPNG7hpZQ&ctype=5&q=&ved=2ahUKEwi02pb1rIWCAxULhVYBHQ_xAW0Q9aACKAB6BAgDEFM&adurl= (https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjSsZz1rIWCAxU12kwCHcpmCfkYABAMGgJ0bQ&gclid=CjwKCAjwysipBhBXEiwApJOcuw9DjsMMuYbSGtFvyJxc9NmSsE-viN-RTQYk7kpZGwKulVzQyk9PKBoCGhYQAvD_BwE&ohost=www.google.com&cid=CAESV-D2xMtXYLFtldxxPT5qrXx4sOIuNZGGkDYQw6WjJeS7Vjt2Yk-cTM7wplq8isPxTQLXg5mGIOjyRdKUVqab3P43fCjF_AB21tq8CxXUP-_mHV9_TjtMog&sig=AOD64_2ofYquLe6EHRuXd7CGnXPNG7hpZQ&ctype=5&q=&ved=2ahUKEwi02pb1rIWCAxULhVYBHQ_xAW0Q9aACKAB6BAgDEFM&adurl=)
Trust me: Once you get to where I currently am, you'll want to have 5 sheets in stock for just in case, so if you can find 19 other likeminded steamers (or bike/car restorers, or whatever), you're in business... :D
That link is exactly the stuff I have and the price is virtually identical.
Forgot to tell: I brought 5 sheets home from work...
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Hi Bert,
Many thanks for the very informative observations on running a steam plant, but may I comment on the fact that we are a dying breed of enthusiasts in model steam boats.
In my club in Glasgow about 15 years ago we had 10 members devoted to steam propulsion, most of us being retired engineers who helped out those with no experience at all and as we were all working to a financial budget no electronic devices were use nor available and doing so our steam members learned how to control the model by experience and by bringing the model into the edge to check boiler levels and a drop of oil.
Unfortunately all of the members except for myself are left and no younger members have been interested in steam power.
Consequently all of our fittings were home made including boilers and engines from castings, so here ids a sketch of a boiler feed feed water heater and oil separator made from scrap copper tubes that were supplied just for the asking at a local plumber free of charge and it now installed in a steam plant.
To empty the condensate all that is required is to close the exhaust steam to the Funnel ( squeeze ) and open the drain valve at the bottom using silicone tube that the flyers use to empty the tank simple but effective.
Once again thanks for your explanation on using electronics.
George.
PS apologies for pics out of sequence.
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Hi Bert,
Many thanks for the very informative observations on running a steam plant, but may I comment on the fact that we are a dying breed of enthusiasts in model steam boats.
In my club in Glasgow about 15 years ago we had 10 members devoted to steam propulsion, most of us being retired engineers who helped out those with no experience at all and as we were all working to a financial budget no electronic devices were used and doing so our steam members learned how to control the model by experience and by bringing the model into the edge to check boiler levels and a drop of oil.
Unfortunately all of the members except for myself are left and no younger members have been interested in steam power.
Consequently all of our fittings were home made including boilers and engines from castings, so here ids a sketch of a boiler feed feed water heater and oil separator made from scrap copper tubes that were supplied just for the asking at a local plumber free of charge and it now installed in a steam plant.
To empty the condensate all that is required is to close the exhaust steam to the Funnel ( squeeze ) and open the drain valve at the bottom using silicone tube that the flyers use to empty the tank simple but effective.
Once again thanks for your explanation on using electronics.
George.
PS apologies for pics out of sequence.
Hi George,
That type of oil separator (minus the feedwater preheater coil) is still being sold by Regner if I'm not mistaken. It is a simple principle, and in a sense it is identical to what I use. Difference is that in my case, the pressure to discharge the slops is generated by nothing else than the diameter of the steam exhaust pipe, and the discharge is continuous, to a separate receptacle.
I need that continuous discharge, otherwise the separator gets filled up approximately halfway the operating duration, and once that happens, oil will escape with the exhaust steam that feeds the preheater/condenser, end up in the reclaimed condensate in emulsified (non-separable) form, and subsequently pollute the boiler.
I divided the functions of oil separation and feedwater preheating over two separate units, in order to obtain clean condensate that can be reclaimed to the feedwater tank.
Steam indeed is a bit of a dying breed, just as wet fuel (more specific, glow fuel) is in the RC aeroplane world. But there's nothing wrong with attempts to revive interest a bit.
Over the past 7 or 8 years I have therefore focused on modifying the small engines designed for glowfuel (expensive and messy, increasingly difficult to purchase) to where they can run on regular petrol and 2-stroke oil, cheap, frugal, easy to buy and lots cleaner.
I have come as far as (for example) a 5 cc fourstroke with electronic ignition and sparkplug, but ALSO electronic mixture control, burning less than 180 ml of fuel per hour, practical, reliably running clean throughout the entire rev range, and extremely userfriendly.
A few people (about 100 worldwide) have followed, and maybe, MAYBE the industry picks up on it. There are a few indications that they do, actually.
That's a bit where I'm coming from.
I do not have the illusion that I can, on my own, generate interest in steam for a new generation, but what I most definitely CAN do, is show folks that it is OK to deviate from the trodden path onto roads less travelled.
There is so much fun to be had, so much to experiment with and so much to learn...
One of the things I noticed in the field of aeroplanes, is that people DO still have an interest in wet fuel, but are turned off by the fuss and the mess. Whenever I demonstrated my engines, there was a definite interest in the long flight times, the ease of operation, reliability and relative cleanliness.
I think that also is the thing that turns people away from steam: the maintenance, the need for control and checks (regularly coming to the edge to check boiler level, oil, etc) and I focused on setting up mine to run basically unattended for as long as I could stretch the operation time.
I like a beautifully built boat just as much as anybody else, but for me, I derive the most pleasure from the knowledge that my steamplant is "optimised" and basically performs like very few out there... And wouldn't it be nice if after posting here, other people will build plants that perform even better than mine?
Wo knows... one day...
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Meanwhile the switch and telemetry-function to activate that switch have been insalled/progged, waiting is for a few "cement resistors" to heat the gastank.
Curious what it will bring...
Well... resistors have arrived, and installing them took all of about 10~15 minutes:
https://www.modelbouwforum.nl/attachments/20231021_153633-1-jpg.557527/
I still need to finetune the setpoint, protect the temperature sensor a bit better against external influences, but it works fine.
As long as I set up the control such, that the gas tank maintains about 13 degrees Celsius, gas pressure remains high enough for the burner to have some headroom maintaining steam pressure at full ahead until the last drop of gas.
Works excellent, heating switches on and off on demand, the load on the LiPo is not at all noticable in the onboard voltage, and I think there is about 2,5 hours of safe steaming in the batterypack.
I'm happy...
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Hi Bert
I do not have the illusion that I can, on my own, generate interest in steam for a new generation, but what I most definitely CAN do, is show folks that it is OK to deviate from the trodden path onto roads less travelled.
There is so much fun to be had, so much to experiment with and so much to learn... .
performs like very few out there... And wouldn't it be nice if after posting here, other people will build plants that perform even better than mine?
Wo knows... one day...
[/quote
Hi Bert
I do hope that you don't feel that my post was criticism of your effort to get as much info out to the forum readers, if so I unreservedly apologise as that was not my intention.
When we were building steam plants and running them such things as the Regner Condensation traps were available and only as the Forum advanced into Europe did these fittings became known and available, the only supplier of fittings was Cheddar and as time went on there were others now available.
I have noticed in the past some steam enthusiast at the end of a run had copious amount of milky white condensate loaded with oil lwhich to me indicated that too much oil was coming thro' the engine.
Here is a pic of my steam tug Cervia which is powered by a Stuart D10, if you notice on the funnel there is a small oil separator which has a feed over board, the engine is fed by only a whisper of oil from the lubricator which leave more or less clean exhaust condensate over board even after a full afternoon of sailing , so can you reduce the amount of oil going into the engine Also a pic of the tugs engine Stuart D10 with boiler feed pump.
Keep up your experiments with your electronics, I do hope that somebody will read them and be converted from electric buggies, aircraft, and fast electric boats.
George..
Must try to separate the blue background
/quote]
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Hi BertI do hope that you don't feel that my post was criticism of your effort to get as much info out to the forum readers, if so I unreservedly apologise as that was not my intention.When we were building steam plants and running them such things as the Regner Condensation traps were available and only as the Forum advanced into Europe did these fittings became known and available, the only supplier of fittings was Cheddar and as time went on there were others now available.I have noticed in the past some steam enthusiast at the end of a run had copious amount of milky white condensate loaded with oil lwhich to me indicated that too much oil was coming thro' the engine.Here is a pic of my steam tug Cervia which is powered by a Stuart D10, if you notice on the funnel there is a small oil separator which has a feed over board, the engine is fed by only a whisper of oil from the lubricator which leave more or less clean exhaust condensate over board even after a full afternoon of sailing , so can you reduce the amount of oil going into the engine Also a pic of the tugs engine Stuart D10 with boiler feed pump.Keep up your experiments with your electronics, I do hope that somebody will read them and be converted from electric buggies, aircraft, and fast electric boats.George..
[/size][/font]
[/size]
[/size]Don't worry, George, I did absolutely NOT take your post as criticism. To be blunt, I'm slightly autistic, leading to "explain myself" when that is not strictly needed, and sometimes people that do not know me, interprete that as me being offended, while in reality, I am not...
[/size]On the bolded: yes, that is what is being collected in the oiul separator, but that crud is NOT representative of the condensate that can be had when condensing the remaining steam.
What is important though, is that whatever is collected in the oil separator, remans there and should never be allowed to pass over into the steam exhaust.
[/size]There is a tiny bit of oil in the remaining steam, but that is so little, that the filtering method I am using, with 100% certainty catches that.
I mentioned somewhere in one of my posts in this thread "People don't pay attention"... That was not meant as an insult to anyone, just an observation.
Way I figured out that virtually ALL the oil is arrested by the oil separator was by simply keeping track of cylinder oil consumption and oil recovered from the separator. Those quantities matched so close that I was sure the oil carried off with the exhaust steam was negligable. Not zero, but so little that it won't be an issue, and condensate filters are fairly easy to construct anyway.
[/size]As for lubrication, I am aiming for approx 0,5 ml/hour, but the adjustment of the displacement oiler is very sensitive to minute adjustments, and unfortunately also very sensitive to external influences (steaming on an Autumn day of 10 deg C lubricates a LOT more than on a summers day of 20 deg C even with the same settings).
One of the things I still want to do is build a mechanically operated, properly adjustable and constant dosing pump. Plenty ideas but none that are executable with my tools and machines (or better, lack thereof... :D)
[/size]Brgds, Bert
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Well... resistors have arrived, and installing them took all of about 10~15 minutes:
https://www.modelbouwforum.nl/attachments/20231021_153633-1-jpg.557527/ (https://www.modelbouwforum.nl/attachments/20231021_153633-1-jpg.557527/)
I still need to finetune the setpoint, protect the temperature sensor a bit better against external influences, but it works fine.
As long as I set up the control such, that the gas tank maintains about 13 degrees Celsius, gas pressure remains high enough for the burner to have some headroom maintaining steam pressure at full ahead until the last drop of gas.
Works excellent, heating switches on and off on demand, the load on the LiPo is not at all noticable in the onboard voltage, and I think there is about 2,5 hours of safe steaming in the batterypack.
I'm happy...
It is easy to say "yeah, it works"... but HOW well does it work?
In the end, I did three tests of each approximately 50 minutes, taking notes every 3 minutes and changing speed every 3 minutes at the same time.
The notes were speed, gastank temperature via telemetry, and gastank temperature via IR thermometer.
First test was without heating installed. I alternated between dead slow, half and 3/4 speed (and I take care that those speeds every time use identical throttle valve positions of course). In the middle of the test, one single run full speed (3 minutes) was done. During this full speed run, the burner near immediately went to 100% and thus boiler pressure dropped below controlled range. Fuel consumption over 50 minutes was 42 gram (fairly normal), and the lowest temperature of the gastank was about 5,5 deg C (ambient at the time was 15 degC). After the full speed run halfway through the test, the burner barely managed to keep up with 3/4 speed, but the gas temperature slowly crept back up to about 7 degrees C. Despite that, performance of the burner system noticably deteriorated (identical engine speed required progressively increasing burner outputs).
This first test showed poor correlation between telemetry read-out and IR measurement, Most likely because the waste condensate receptacle is near to the temperature probe affecting this read-out. So I placed an insulating cover made out of Balsa over the probe.
2nd and 3rd test were done the same way, BUT only alternating between half and 3/4 (no more dead slow periods) to keep up the fuel demand, and full speed runs at 15 minutes, 30 minutes and 45 minutes approximately.
Because of the insulating cap over the probe, correlation between telemetry and IR measurement was improved to the point of "usable" but still not great. Heating switched on and off during the first part of both tests, and basically remained on after approximately halfway, so there IS some form of control, but it's a bit ambiguous and I could not really see a firm correlation between boiler load and heat demand.
The setpoint of the heating was chosen such that it switched on around approx 13 degrees actual (IR) tank temperature.
Results were positive: Both tests the burner remained below 100% output even during the last full speed run (albeit barely) and in fact, during the 2nd test the burner ran out of gas within seconds after the last full speed run. Just poof, empty, sudden flame-out, no gradually dying fire: I reduced speed to half, burner responded by reducing fire, and maybe 30 seconds later the flame extinguished without first growing smaller. Just like that. Rather surprising actually, hadn't seen that before.
Both tests the IR measured temperatures by and large remained around 12~12 degrees, with outlier observations of around 9 degrees.
One thing that was interesting:
I use a 30/70 propane/butane mix. Normally the propane burns off first, leaving the Butane for last, leading to pressure, and thus performance drop.
That is the reason that I usually blow off the remains of previous session, because this is mainly Butane, and leaving that in the tank results in lower Propane content in the freshly filled tank, thus lower performance.
For the purpose of testing, the 2nd test I did NOT blow off this residue, and despite that, I had basically full burner capacity throughout the entire test.
Because I ran out of fuel at the end of 2nd test, the 3rd test was done with "fresh" 30/70 mix, so performance was better and tank temperatures remained higher, there is a visible difference, but blowing off fuel remains has become obsolete now, which is another 15~20% fuel savings overall.
Dang, this thing is going to make me RICH... (or at least less poor... :D :D :D )
As a side note: the third test brought the runhour counter to about 49 hours in 4 months time... As a comparison: I also am a VERY avid RC flyer, but most of my plane engines barely manage 25 hours per year.
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Yesterday I decided to "Ogre-test" the gas tank heating, by raising steam, and putting the thing at full throttle, regardless.
I had to cut back after 15 minutes because the Feedwaterpump did not even come close to keeping up by about half.
So today I found an unused Futaba S9254 (a very fast servo used for tail rotor of RC helicopters). This servo not only has about 50% more torque than the up until now used S3001 (3,3 Ncm versus 2,4 Ncm for the 3001), it also is about 4,5 times faster (0,36 sec/revolution vs 1,7 sec/rev).
The S3001 managed somewhere in the vincinity of about 600 ml/hr, so theoretically this thing should be able to do well over 2 litres per hour.
The external housing dimensions are identical, so even if the fit is not perfect (the Regner pump was made for a different servo), since the 3001 did not present any issues, the 9254 should not either.
Modification is really simple: remove the pot-meter driver, and remove the cam on the output shaft that prevents the servo from rotating continuous. All in all a 10 or 15 minute job, really not hard.
Exchanging the 3001 for the 9254 was maybe 5 minutes.
https://www.youtube.com/watch?v=t2Tgj_PLs14
So... Repeat Ogre-test :D
Results:
Started out with 60 grammes of gas and after raising steam and warming up the engine, full throttle it is...
Inbetween I had the time to adjust the feedpump curve to match this new pumpdrive. Turns out, the pump needed a leisurely approx 1/3 of full capacity to keep up with steamproduction at full throttle.
20 minutes in, the burner reached maximum setting (meaning the heating can't keep up, I'll get back to that). Full burner occurs at 1,4 bar.
Yet, despite the burner not being able to give it more, the boiler virtually held pressure for another 10 minutes at least.
24 minutes in, the feedwatertank reached low level, but since this was not an endurance test but a performance test, I refilled.
30 minutes in, the gas tank temperature, that remained more or less constant, started to slowly rise again, indicating that basically most of the Propane was gone from the mix. The boiler at that time was about 1,3 bar, but now started to drop a bit quicker.
35 minutes in, boiler pressure was 1,2 bar.
38 minutes in the boiler dropped to 1 bar, triggering the low pressure alarm.
near to the second exact, 40 minutes in the fuel was through, flame extinguished at a boilerpressure of 0,8 bar.
Reason the gastank heating can't keep up, is that at full ahead, apparently the burner went through about 56 grammes in 40 minutes, equalling 1,4 g/min.
The heating, at 5W was intended for about 0,8~1 g/min because so far, that had been my average fuel consumption.
Not going to do anything about that, because apart from testing, I won't be doing continuous full ahead anyway.
Going through a feedwatertank in 24 minutes means that including condensate return (estimated to be about 100~125 ml in 24 minutes), the boiler at full ahead is generating somewhere between 1,1 and 1,2 kilogram of steam per hour, and frankly, that is quite impressive for such a tiny thing.
Further, some testing revealed that the preheater has ample overcapacity, even running the feedpump at full speed the feedwater temperature did not drop, AT ALL... Funny thing: With the feedpump at full speed, and the steam engine at dead slow, all supplied steam is condensed and the venting of excess steam stops. Switching the pump back to auto (feedrate matching the boiler) steam reappears at the funnel.
All in all I'm getting happier and happier.
And as a side note (pay attention, Derek!) the S9254 is amazingly quiet, even under load:
https://www.youtube.com/watch?v=5W4O1Wt0yCk
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Bonjour Bert,
Oups, I have found this servo on Internet but at a price of about 95,00 € without shipping :((
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Bonjour Bert,
Oups, I have found this servo on Internet but at a price of about 95,00 € without shipping :((
Yes... that is price for a new one. But it is a bit silly to buy a new one, and especially THIS one because a servo half the speed of this one can allready do the job.
Since this type is about 25 years old, it is fairly obsolete, and I have bought them used for as little as 20 Euro, although prices for 2nd hand vary with the seller of course.
The one I fitted in my boat also was one I bought used a few years ago.
But it does not HAVE to be the 9254, or even an equally fast one for that matter. Let's face it, I have almost 2,5 litres per hour pumping capacity, and that kind of water can even sustain a Stuart D10 or similar...
I am pretty sure there are OTHER servo's with similar or lower specs that can do a good job. This servo I use now, has a rotational speed of 0,36 sec for a full revolution.
Realistically I can allready run continuouls full power with about 0,6~0,7 sec per revolution.
This servo: [size=78%]D-Power 570 BB MG – Hobby-In (hobbyin.nl) (https://hobbyin.nl/product/d-power-570-bb-mg/)[/size] would allready do the job, has metal gears and ballbearings, and can handle probably well over 7 bar (if I would have to guess, maybe up to 10 bar, but who needs that???).
It costs only €22,50 NEW...
This one can do the job as well, and only costs only €16,50: [size=78%]D-Power 555 BB – Hobby-In (hobbyin.nl) (https://hobbyin.nl/product/d-power-555-bb/)[/size]
Little bit less pressure, but should still handle 5 or 6 bar without problems.
Those are European (Dutch) store prices, I am sure both these servos can be found on the internet cheaper than that.
The Regner pump itself (the pumping part, I mean) holds out pretty good. It's a shame they don't sell the top part separately so people can use a servo of their own choice.
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This afternoon the milestone of 55 runhours was left in our wake...
https://www.youtube.com/watch?v=SszawqNUNMs
Three improvements were done in the past week
The power supply in the boat is now a stabilized 5,2V, the gas tank heating significantly improves burner performane (which in turn makes the boiler pressure more consistent), and the digital servo for the feed pump not only is quite a bit faster, it apparently also displays a much more stable performance.
All three are tiny improvements, but apparently these tiny improvements affect and amplify each other, because whichever way, I have never seen the water level so consistent and constant throughout a run.
I did not time myself this time but if I had to estimate, this was a 40~45 minute run judging by the water left in the feedwater tank, I started out with the level glass filled to the middle of the glass to my best ability, and at the end I really could not tell whether the level went up or down. To the eye it was exactly where I started out.
And as y'all can see, the boat handles really well and allows for pretty precise low speed manouvering, coming alongside the tugboat.
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As a loose remark:
Lat time out for the boat was 9 or 10 days ago, and I expected to bo sail it in the last week, so I had the boat prepared (Battery, gastank and boiler filled/charged) but the totally crap weather with little expectation for improvement...
Did not want to store the boat like that because in a week or two I have to go to sea again.
So I ran it in order to discharge the battery, burn off the gas tank filling, get some oil through the engine and some water through the boiler.
Afterwards checked boiler water quality before discarding it and found the water to be a perfectly expected 25 ppm TDS (normal value after 4 hours of steaming).
This leads me to believe that during storage there seems to be virtually zero chemical action going on, since (at least, that is my expectation) any corrosion, dezincification or other chemical process would increase this TDS value.
No shocking news whatsoever, but it is good peace of mind to know that at least short term nothing happens when a boiler is left standing with a used water filling.
I thought, some of you guys might want to know.
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Bonjour Bert,
On my side, I don't mind leaving gas in a tank even for a short while but I always empty completely my boilers and let them open to let them dry.
Furthermore, I don't always use demineralized water because I have been told that it seeks to remineralize, so I mix my navigations with tap water (fortunately not limestone).
And I use my whistles to clean the ears of my fellow citizens ok2
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Bonjour Bert,
On my side, I don't mind leaving gas in a tank even for a short while but I always empty completely my boilers and let them open to let them dry.
Furthermore, I don't always use demineralized water because I have been told that it seeks to remineralize, so I mix my navigations with tap water (fortunately not limestone).
And I use my whistles to clean the ears of my fellow citizens ok2
It does... that is why I use destilled water, not demineralized.
The difference between the two is that in demineralized water, the scale forming ions are exchanged for non-scaleforming ones. Meaning it still contains ions and thus shows some form of reactivity.
Destilled water contains nothing.
But BECAUSE I use destilled water, I don't want to waste it, so I leave the water in the boiler between regular use, as the water quality remains within acceptable limits for at least 6 or 7 hours of steaming. I replace every 4 hours or so, to stay on the safe side.
As it is, I still have zero scale in my boiler, as far as I can see.
A destiller can be bought for as little as 75 Euro new (if you pay attention and shop around). I run my destiller in the weekend, when electricity is cheaper, and especially in winter the water then is for free because that thing produces a fair bit of heat, enough to make the central heating switch off, so I am not burning any gas to heat my home...
I don't use (even don't HAVE) a whistle, it's a waste of steam that I rather use to push my boat 5 cm through the water :D :D :D (just kidding... Being used to ships horns, I don't like the shrill high pitched sound of steam whistles).
I normally leave the gas in the tank, but not if I have to leave my home for 2 months. You never know what will happen, I prefer to have my gas stored in approved containers when I'm not home.
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Continueing the "pimping"... :D
My feedwater preheater only returns about 25~30% of the total steam at best (and I think closer to 25 than to 30) and I want to increase that number.
For that I need of course a cooling water supply, and it should (as a theoretical minimum) be around 70 ml/min
I don't want to mess with pumps (they rob a tiny bit of power from the shaft) and gears/belts/whatnot to drive that pump (robbing typically even MORE power) so I am going to use a "double" water pick-up: A water inlet in the high pressure area behind the propeller, whose "delivery pressure" will be supported by a water return in the low pressure area in front of the propeller. With a bit of luck, this will also reverse the waterflow when running astern.
Now the easiest way for such a pick-up is to drill a hole in the boat and simply glue a piece of brass tubing in. But the most "streamlined" thing to do would be to integrate it in the rudder. The existing rudder is a no-go, but a new rudder is easily made.
https://www.modelbouwforum.nl/attachments/20240223_143237-1-jpg.572784/
While I'm at it, Borkum loses a lot of speed with the rudder hard-over, and does not turn very tight at rudder angles that do NOT rob speed. So I thought I would like to experiment with a Fishtail rudder while I'm at it. No particular reason, just to see what it does... :D
End of tomorrow I hope to be able to report on at least the water flow...
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Bon Courage :-))
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Merci beaucoupe!
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The curing of the resin to build the rudder took a bit longer than expected, but the rudder is taking shape.
It is a bit shorter than the original rudder, because I started the waist of the fishtail profile a bit too early and I had to cut a narrow ridge off the trailing edge to prevent the fishtail to become too shallow and too blunt. The entire effect of the fishtail is in that the water is sharply accelerated sideways very close to the trailing edge, so it is imperative that the waist is not too far from that trailing edge.
https://www.modelbouwforum.nl/attachments/20240223_235559-1-jpg.572889/
The profile is getting there, it still needs to be a bit thinner at the waist, and symetry is not yet what it is supposed to be, but it's midnight here, so I'm gonna call it a day.
https://www.modelbouwforum.nl/attachments/20240224_000134-1-jpg.572890/
Curious how this is going to work out. I have seen Becker rudders in model ships, but I can't remember having ever seen fishtail rudders, leave alone anyone that replaced a normal rudder with a fishtail and reported on the differences.
Fingers crossed...
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And since time does not take lunchbreaks either...
The rudder was made to fit in the propframe. here it still needs filler and paint.
https://www.modelbouwforum.nl/attachments/20240224_130517-1-jpg.573014/
On the topside, the water tubing connected and checked if it clears the hatch and allows for the rudder movement:
https://www.modelbouwforum.nl/attachments/20240224_130521-1-jpg.573015/
Next step, while the boat was "opened up" anyway, was the installation of the water exhaust. It is in front of the prop, in order to utilize the low pressure in front of the prop as assistance for the pick-up pressure.
https://www.modelbouwforum.nl/attachments/20240224_142320-1-jpg.573016/
I cut the tube so that it will end as closely to the prop disk as I could get it, all to maximize effect.
https://www.modelbouwforum.nl/attachments/20240224_142415-1-jpg.573017/
Now the waiting is for the glue, resin, paint etc etc to cure...
Boring...
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Short report, tried to get video and such, but since the feedpump failed from the start, I could not get "data" (differences in runtime on the feedwater tank, etc etc).
But I managed to determine the following: it looks like the waterflow is just about right for what I hoped to achieve, but "not abundant".
The propwash is NOT sufficient to fill the system by itself. But if pre-filled, the system flows, and the reversal also works.
The fishtail rudder seems to indeed have better steering effect, and this even with a slightly reduced maximum rudder angle.
Pretty bummed out about that Regner feedwater pump.
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Bonjour Brutus,I was also very disappointed with my Regner feed water pump. this is why I kindly suggested you to use a Microcosm one with an enhanced engine:
https://www.youtube.com/watch?v=FNy_x-RR9mE (https://www.youtube.com/watch?v=FNy_x-RR9mE)
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Bonjour Brutus,I was also very disappointed with my Regner feed water pump. this is why I kindly suggested you to use a Microcosm one with an enhanced engine:
https://www.youtube.com/watch?v=FNy_x-RR9mE (https://www.youtube.com/watch?v=FNy_x-RR9mE)
I was not too impressed with the Microcosm item either. I had one, but I cannibalized it for one of the connections, rendering the rest of the pump useless.
Not sure what I am going to do. The Regner pump appears to be servicable, but I need a magnifier glass and a good light source since the internal parts are very tiny. It seemed there was some dirt in the pump jamming the valves.
Tomorrow, after a good nights sleep another try.
But I am happy that the cooling system appears to work...
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Important update:
The pumping element of the Regner pump turns out to be VERY servicable:
The thing is SO tiny, that the suction valve acts a bit like a filter: Fluff in the water catches in the suction valve, messing up its function.
I could not get a better pic, but for reference, the valve disk itself is approx 3,5~4 mm diameter, the valvestem maybe 1 mm dia, and 2 mm long.
There is a tiny plastic (unknown which, most probably teflon or such) seal on the disk.
https://www.modelbouwforum.nl/attachments/20240225_112125-1-jpg.573095/
Recommendation is to use a strong light, and use a piece of A4 printing paper as work surface.
Mark the parts for proper re-assembly (I made a diagonal scratch along the outside before disassembly, marking how things were supposed to go back together again).
The bolts holding the element together are 3 mm hex head, and the only tool I could safely use was a 4" Bahco adjustable spanner.
The plunger gland seal can be made by taking about 3,5 cm of PTFE tape twisted to a tiny cord, wrapped around the plnger and into the gland cap nut.
A bit of PTFE grease and carefully tightening it with running pump does the trick.
The quality and servicability surprised me, actually.
Test run (hopefully with decent video) in approx 30 minutes from now (posting will take longer of course, the test run should be at least 30 to 50 minutes in duration).
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Going to do the video at a later time (need some editting/cutting) but first conclusions:
I seem to be having at best about 60 ml/min, which is marginally enough, IF the coil is inside the condenser instead of outside.
One thing I completely overlooked, is that water has air dissolved in it. When water gets hot, this air gets released, leading to bubbles in the warm water return line. This reduces waterflow and at half speed, the waterflow simply stops. It does return when going to full ahead again, but this was something I had not thought about.
A pressure cone might bring some improvement,
Also: the bathtub is NOT 100% comparable with a free flowing hull, the waterflow significantly changes with the hull free moving through the water.
Improvement can be had from placing the condenser "as low as possible" in the boat"
Does it have a measurable effect?
Most definitely, I did the test running full speed all the time, and very roughly calculated, the feedwatersupply lasted about 20% longer (timer was set at 25 minutes, low level was however reached at around 30 minutes).
We're not done yet... :D :D :D
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Apologies, the promised video failed.
But meanwhile I did some calculations, and damn! I love it when theoretical physics (Bernouilli) turns out to be true: The smaller I made the inlet cone, the better the cooling system performed.
The straight open pipe (3 mm inner diameter, all subsequent piping also 3 mm inner diam all the way to the end) of the pick-up worked.
(https://www.modelbouwforum.nl/attachments/20240223_235559-1-jpg.572889/)
A small piece of 2 mm inner diam silicone tubing slipped over the pick-up increased flow,
(https://www.modelbouwforum.nl/attachments/img-20240225-wa0005-1-jpeg.573342/)
and an even smaller cone (approx equivalent to 1,5 mm diameter) that I made out of heated and stretched Sullivan bowden cable outer tube worked even better.
(https://www.modelbouwforum.nl/attachments/20240225_223255-1-jpg.573431/)
Based on estimated prop wash velocity, I calculated that approx 7,5 cm of water column above waterline should theoretically be possible, and with the smallest inlet cone I actually managed to achieve that.
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Surprising and interesting ! How to explain that ??
Thanks to share you tests for the benefit of all ! :-))
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Surprising and interesting ! How to explain that ??
Thanks to share you tests for the benefit of all ! :-))
Bernouilli's law... That is a very tricky part of physics and leads to very counterintuitive results.
If a flowing liquid is forced to change velocity, pressure changes An increase in velocity lowers pressure, a decrease in velocity increases pressure.
The velocity in the propwash is about 1,25 m/sec, the velocity in the ctubing is in the order of magnitude of 0,2 m sec.
Now if the pipe is straight, and water is not compressable, the velocity in the opening of the pick-up tube is identical to the velocity in the rest of the tubing, 0,2 m/sec. This means that the water has to decellerate very suddenly in front of the tube, and thus the high pressure area is (some distance) in front of the tube. A bit like a bow wave.
In front of the tube there is nothing that forces the water to go IN the tube, and nothing to contain the pressure, so most of the water flows off to the sides, a bit like a bow wave in front of a blunt bow: here the high pressure area also occurs some distance before the water actually hits the bow.
Now if we make a pick-up opening that for a velocity of 1,25 m/sec passes the same amount of water, as would the tubing of 3 mm internal diameter at 0,2 m/sec, we would end up with an inlet opening slightly smaller than 1,5 mm diameter. Now the water passing the cooling system at 0.2 m/sec can ENTER the system at 1,25 m/sec, which means that the pressure change will occur IN the tubing, AKA "enclosed, and none of the water and pressure can escape. now the conversion from velocity to pressure occurs IN the tube. If that is a stepwise increase of diameter, turbulence will occur. Not ideal.
But if we make that increase gradual (AKA diverging cone) there won't be turbulence, velocity change is gradual and maximum pressure is generated.
It took me quite a bit of time looking at the formulas that represent Bernouilli's law before I actually understood what happens.
Intuitive, people would want to make the inlet funnel-shaped in order to "catch the water" but it does not work like that, and a funnel shaped inlet only makes things worse: The inlet diameter increases, which means the high pressure area allready starts at a greater distance in front of the inlet, and water has more incentive to escape sideways.
Decreasing the inlet diameter to where the velocity in the opening is equal to the surrounding water of the propwash, there IS NO velocity change in the inlet, therefore no high pressure area BEFORE the inlet, therefore no water and pressure excaping sideways.
As i said, very counterintuitive, but once you "see it", it is actually quite logical.
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And suddenly it dawned on me: The intake opening determines the POSSIBLE water amount per unit of time (propwash velocity times intake opening cross section results in a volume per unit of time).
The rest of the cooling water tubing determines whether that volume can actually pass given the resulting backpressure.
Highest delivery pressure achievable is with the smallest nozzle opening that will allow the required flow.
I know that I need to condense about 7 grammes of steam per minute, and for that I need an absolute minimum of 60 ml/min, but to allow for some headroom, let's make that 75 ml/min, not only for headroom but also because of ease of calculation:
With a propwash velocity of 1,25 m/sec, that velocity can be expressed as 75 metres per minute...
75 ml/min (ml is cubic cm) divided by 7500 cm/min results in a cross section of the inlet of 0,01 cm2
0,01 cm cross section means an inlet diameter of 1,13 mm.
I don't have that drill...
1,1 mm diameter has a cross section of 0,0095 cm squared, resulting in a maximum possible waterflow of 71,3 ml min.
Should be sufficient. I should be able to make something like that.
EDIT:
Just as a check, an intake of 1,2 mm should flow 84 ml/min but probably the current tubing won't pass that (just a hunch).
But the easiest way to make something like this, would be to turn a conical dowel on the lathe (narrowing down to zero), and use that as a mold to make the internal cone from either Silicone or resin, then cut the cone to length to get the desired inlet opening. That would mean I can make several, and experiment.
Going to be a fun and educational project...
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This is very interesting. And leads me to believe there must be an optimum opening diameter for a given water speed and tubing size.
Since you have both ends of the cooling tube under water so there is no visual of the water flowing, how can you check the system is actually working?
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This is very interesting. And leads me to believe there must be an optimum opening diameter for a given water speed and tubing size.
Since you have both ends of the cooling tube under water so there is no visual of the water flowing, how can you check the system is actually working?
Theoretically, optimal opening size is where the velocity of the propwash passes the water the system will accept. In reality bit larger due to the viscosity of water.
For now I can check flow visually by means of airbubbles, and by the temperature difference between inlet and outlet.
When the condenser has its final form, it also should be visible at distance by the presence or absence of a steam plume.
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Chapeau :-))
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I see that I have not kept up with the updates.
I made a "mold" of sorts to fabricate a decent pitot-nozzle.
Pretty much a simple piece of roundbar 4 mm turned to a cone.
(https://www.modelbouwforum.nl/attachments/20240309_164959-1-jpg.574983/)
Coated the mold with wax, wrapped a bit of Epoxy soaked tackling yarn, and let it cure.
(https://www.modelbouwforum.nl/attachments/20240309_165023-1-jpg.574984/)
This allowed me to fabricate several identical nozzles, which I could drill out to size for experimenting.
(https://www.modelbouwforum.nl/attachments/20240309_165826-1-jpg.574986/)
1.2 mm was what I ended up with.
Secured with a bit of silicone tubing, this is the endresult:
(https://www.modelbouwforum.nl/attachments/20240309_170508-1-jpg.574988/)
looks hideous, but all that matters is the shape and dimensions on the inside. Those determine effectivity.
Now I still had the coil on the outside of the condenser, and that is a miserable design: Heated water releases its dissolved gasses, these gasses remain trapped in the high points of the windings, and each airpocket represents a bit of height difference, that the pitot tube has to overcome. As long as I held full throttle, the undisturbed system would keep going all by itself for about 20 minutes, then the collected air would stop the waterflow.
But even with a "fresh" system (no air build-up yet) below 3/4 power the waterflow would stall, and was very reluctant to restart on full power.
With a bit of tapping against the lines I could dislodge that air, and keep the system going, but that is not how it should be.
When reversing the engine, sometimes the waterflow would reverse, sometimes not. Also not very desirable.
With this coil (1 metre of 4 mm copper tube wrapped around the condenser shell) I managed to stretch endurance from about 25 to about 30~31 minutes of continuous full speed.
So I decided, just as a proof of concept to see what a horizontal "coil" inside the condenser shell would do. Since inside most space was taken up by WAAAAAYYYY too much preheater coil, I could only fit about 20 cm of condenser tube, just once forward and back.
the result was remarkable: Despite only 20 cm of steam-exposed cooling tube, I gained another 4 minutes of full speed endurance. Absolutely not bad.
What was even better: The waterflow maintained itself, water pressure at full speed was strong enough to dislodge any trapped air. Waterflow easily and reliably reversed itself when the machine was reversed, and at least in forward direction, waterflow kept going reliably at 3/4, most of the time even down to 1/2 power, and restored itself every time above 3/4 power.
(https://www.modelbouwforum.nl/attachments/20240421_204821-1-jpg.580758/)
Next step will be to shorten and rearrange the feedwater preheater coil, in order to create more space for one extra loop (additional 20 cm) of condensing coil.
And I think I will leave it at that... 40 minutes of full power is enough.
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I have hit a snag in that I seem not to be able to keep waterflow over the condenser with the pitot-tubes. It is somehow a combination of things, because the pitot-tubes can do the job, but as soon as steam is introduced in the condenser, things grind to a halt.
I still have slight hope that the pitot-tube will work better in free sailing conditions, but not optimistic.
So I took the liberty to order a miniature electric pump designed for continuous duty.
Meanwhile I made a "lab set-up" with external waterfeed, and the results are pretty much everything I hoped for and then some...
See for yourself:
https://www.youtube.com/watch?v=hnOM9LrzXeM (https://www.youtube.com/watch?v=hnOM9LrzXeM)
As I am writing this, the engine has been running for about 20 minutes at the highest speed the fuel supply allows (10 minutes "balls out", the gastank cools down and I have to rely on the tank heating, which can sustain about 90% of max output).
In this 20 minutes, with only feedwater preheating and the condensate from that, the feedwatertank level would drop at least 30~35 mm.
Right now I am looking at a level drop of 5, maybe 6 mm in the same time...
The condensate return filter has no issues keeping up and the condensate is of absolute brilliant clear quality.
The last 5 runs I would, including raising steam, burn about 35 grammes of fuel for an approx 30 minute run, and then the feedwater level would force me to stop, with about 10~15 grammes of fuel left. Meaning there should be somewhere around 45 minutes of "full power" (meaning "as much as the burner capacity allows") availlable.
Now I am planning to run out the fuel, to see how much water I still have left.
EDIT: it took between 45 and 50 minutes (did not note the exact time of start, sorry) to run out the gastank. All this time I kept the steam regulator such that the burner just kept about 100% fuel supply, otherwise the feedpump does not keep in sync with water consumption.
I have a watertank with 50 mm water (appr 360 ml) in it at start. Normally in 25~30 minutes, about, waterlevel has dropped to 10 mm (70 ml) remaining, and I am forced to stop or the feedpump might run dry.
Now I went all the way until empty fuel tank (45~50 minutes) and remaining feedwater level was 37 mm (appr 260 ml).
To bring this in practical terms, IF I get a reliable cooling water supply going, I can reduce the size of the feedwatertank by about half and still be safe for a complete fuel charge. The size and weight reduction of such tank would MORE than compensate for the installation of a cooling water pump.
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Bonjour,Quite interesting exercize indeed !
I am a little bit suprized by the design of the condenser itself.
To my opinion, as you can't install an efficient cooling system for the condenser, it could consist of pipes installed in the water under the hull.
Furthermore, it would simplify your current piping.An example on one of my boats, at the beginning of the video : https://youtu.be/g3HkvoJdweo (https://youtu.be/g3HkvoJdweo)
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I ran a 2nd test today, this time a bit more aimed at practical use.
I may have mentioned before, that I have "marked" 3 speedsettings in the TX, for ease of manouvering, which are "dead slow" (lowest the engine will keep running reliably), half, and "cruise".
Cruise is the speed I can run from beginning to end with the burner remaining in the controllable range, and is about 75% percent of max power.
As long as I use lower speeds every now and then, occasional bursts of full power are no issue on the pond, so running continuous cruise settings is fairly representative of normal pond-use.
This test, for measuring purposes, I fitted a throttle valve on the watersupply, in order to be able to measure the required waterflow.
Not gooing to bore you guys with a full description of the test, but testing showed that for full power, I need 100~110 ml/min of cooling water to condense all steam (steam exhaust remaining dry) and at cruise speed, this volume flow was 75 ml/min, give or take. Cool! Means that I won't need a big pump.
I started out with 60 grammes of fuel, and after raising steam, I basically set the engine at "cruise" and just waited to see what would happen.
Engine run lasted 58 minutes, with a waterconsumption from the hotwell equalling 80 ml.
55 ml was accounted for in the oil separator and the lubricator, so I am apparently losing only 25 ml of water in 1 hour of runtime.
About needing a pump:
I ordered this one: https://www.fruugo.nl/dc12v-5w-miniatuur-food-grade-borstelloze-dc-dompelpomp/p-122360316-257205194?language=nl&ac=bing&msclkid=6c5041651ee3169be8fc274272234dc3&utm_source=bing&utm_medium=cpc&utm_campaign=All_NL&utm_term=4575136606006185&utm_content=NL (https://www.fruugo.nl/dc12v-5w-miniatuur-food-grade-borstelloze-dc-dompelpomp/p-122360316-257205194?language=nl&ac=bing&msclkid=6c5041651ee3169be8fc274272234dc3&utm_source=bing&utm_medium=cpc&utm_campaign=All_NL&utm_term=4575136606006185&utm_content=NL)Smallest I could find with best efficiency. Going to "trim it down" as far as possible, so with a bit of luck I am looking at less than 2 Watt while still habing ample flow, which would be acceptable.
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Bonjour,Quite interesting exercize indeed !
I am a little bit suprized by the design of the condenser itself.
To my opinion, as you can't install an efficient cooling system for the condenser, it could consist of pipes installed in the water under the hull.
Furthermore, it would simplify your current piping.An example on one of my boats, at the beginning of the video : https://youtu.be/g3HkvoJdweo (https://youtu.be/g3HkvoJdweo)
I cannot use that system... It won't cooperate properly with my oil separator (a condensing pipe below the waterline would create higher backpressure, and my oil separator needs to be more or less "atmospheric" or it will blow the oil everywhere).
Also: I started with a feedwater preheater initially, which never was thought of as a full condenser. It's location was above the hotwell for easy condensate return.
Initially I miscalculated the preheater, so it was way too large, large enough to be a full condenser AND a preheater at the same time.
The piping is not very complicated, but I have to admit that the water pick-up tubes did not work the way I had envisioned it.
I am not too worried about that, because I found a very affordable, very tiny centrifugal waterpump with low power requirement, designed for continuous use (brushless motor technology similar to what is used in computer cooling fans).
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Pump delivery date is now stated as "approx 10 May"...
So for the time being, I'm going through my old discarded fieldbox fuel pumps. There should be one or two that I could get back to life, if even temporary...
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Found an old Volvo windshieldwiper pump, that I got from a salvage yard at least 20 years, and which has been used for glowfuel for at least 10 of them.
I tested how low it would go, and it managed to run reliable at 2S NiMh with a very accptable current draw (I can't measure it any more accurate than "maybe 600 mA") and a waterflow of about 300 ml/min, which is 3 times what I need as minimum. Initially it displayed a dissapointing amount of leakage on the shaft seal, but I simply solved that by reversing the polarity AND the in and oultlet: Now the sucion pressure is active on the shaft seal, and air will leak in instead of water leaking out. Problem solved, boat dry again.
Turned an old receiverpack of 1900 mAh into 2S2P (2,4V, 3800 mAh), and this combo has to do the temporary job of cooling water set-up. It provides me with more cooling duration than I need for now.
Tested this set-up on open water, functioned flawless for 40 minutes, and then a big rainshower spoiled all the fun.
45 grammes of gas, less than 100 ml of feedwater consumption, boat functions flawless, it is a bit of a weird visual, a steamboat with ZERO visible plumes above it, running and running and running and a feedwatertank that barely drops in level.
Fantastic!
Whatever my next steamboat will be, it WILL have a full-recovery condenser set-up... Whether engine driven or electrically driven cooling pump remains to be seen, but full recovery, that is a given! It is worth it. Not because of cost, but because of ease of use (I don't need to bring a jerrycan of water if I go to the pond...)
Can't wait until the brushless pump from China will arrive, after which everything can be installed below deck , and the original visuals of the boat can be restored.
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Behold! A steampowered boat with NO steam plume above the funnel! The way it should be!
https://www.youtube.com/shorts/u0jqCW-Cn6M (https://www.youtube.com/shorts/u0jqCW-Cn6M)
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In a dutch forum, when I reached 40 runhours, someone commented that the quality of this engine was apparently, based on my reporting, much better than expected. The subject of that thread is the question whether the "cheap chinese machines" are worth considering or not.
Suffice to say, any prejudice I had, is gone and they absolutely ARE worth considering.
Today, I have landed at 70 runhours, and re-reading that forum I stumbled upon that old post from back then.
This is the comment I posted today in that thread (ran it through Google Translate of course, duh...), because I simply wanted to share my thoughts here as well for those that have the same question I had (whether these engines are any good):
In the meantime I can report that I have almost 70 operating hours, and the machine is still running without any visible deterioration, no mechanical rattles, no obvious play or clearances, the Stephenson arches do not rattle (although I am quite precise with lubricating them), the performance does not deteriorate, the steam consumption is quite constant, the behavior of the machine, for example when reversing under load or running extremely slowly, does not change. The crossheads are still tight, both in the guideways and in the crosshead pins, and the piston rod seals have not yet shown any visible deterioration. The seals of the control valve rods show some steam oil leakage, but that is actually a good thing, because that oil helps to lubricate the Stephenson arches. Ditto for the piston rod seals: No steam leakage, and the oil that escapes helps keep the crossheads in condition.
BUT ALSO: The gas tap on the gas tank, main steam valve, feed water valve, steam control valve, etc., not only still function flawlessly after all this time, they are also all still 100% tight on both the valve itself and at the spindle gland. The functioning of these items is what keeps an installation safe to operate IMHO...
The steam regulator does not close 100%, but it never did and cannot be expected from a stopcock of this construction. It also does not have to: a minor leakage her assists in keeping the engine warm when stopped.
The parts in the installation that appeared to work less smoothly were the RC controlled burner regulating valve and the feed pump, and both were from Regner, not Microcosm...
They are also working well now, by the way.
I am absolutely aware of the fact that the machine as delivered out of the box and used without further consideration with regard to lubrication and water quality will probably show significant deterioration within a few dozen of runhours. But I think that goes for most engines.
Virtually all engines come with simple oil cups on the bearings etc etc, which is nice for bench runs, but not for "active duty". IMHO, wickfeed oiling is the only way to go.
The fact that this brass engine lasted 70 hours with all signs suggesting that it will last many hundreds of hours to come, that speaks volumes.
In short, the basis of the machine is 100% good, it is a "machine with potential", so to speak. Install proper lubrication (wick feed), and polish the running surfaces of the steam slides (the only thing I can really fault my engine for), keep an eye on your water quality, and the thing will work as well as any other machine.
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Post below fixed, Admin :-))
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Post below fixed, Admin :-))
Thanks Martin! I seem to very much NOT get along with the "editing programming" of this site. Happens quite often that I quote a post or try to edit a message and suddenly the entire format (sizes, fonts etc) have changed completely...
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Computers ..... Just keep posting, I'll fix anything the Matrix breaks! :}
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You da man!
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https://www.youtube.com/watch?v=WJJe1eHWLmw (https://www.youtube.com/watch?v=WJJe1eHWLmw)
Select subtitles and set to auto translate to your language of choice to know what the hell I am babbling on about.
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While I'm at it, Borkum loses a lot of speed with the rudder hard-over, and does not turn very tight at rudder angles that do NOT rob speed. So I thought I would like to experiment with a Fishtail rudder while I'm at it. No particular reason, just to see what it does... :D
On this part (post from end of Februari) I can now finally, after about 90 minutes or so on open water, report that indeed a fishtail DOES make a difference.
I have the vague impression that the boat turns about the same with a reduced rudder angle, losing less speed, but those differences are small.
What is not small, is the differnce in "feel" of the boat. Steering is more defined and sensitive, while straight-run stability seems to have improved. Also at lower speeds. I have to say, I like that. For example, control during short kicks ahead seems to be a lot better.
Steering when backing up however has noticably deteriorated. That is a bit of a shame.
Bottom line is: a fishtail rudder DOES make a difference (bad or good is anyone's own to determine) which in all fairness, was not something I really expected.
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Yesterday (Sunday) a demo-day at a townsfair...
Unfortunately pretty big winds and some rain. but the boat not only handled the weather well for 2 hours in runs of 30 minutes, the organizer had 5 of those "Dicky tugs" availlable for the kids to have a go... Now these kids, well, bumpercars come to mind describing their boat handling skills...
Ravika Putri did not back away from the brawl, and stood her ground... :D
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The intended coolingwaterpump has arrived (about a week early, but I'm not complaining :D)
(https://www.modelbouwforum.nl/attachments/20240503_200022-1-jpg.581890/)
This pic for size (housing diameter vs thumb)
(https://www.modelbouwforum.nl/attachments/20240503_200028-1-jpg.581891/)
The brass tube is not part of the pump, just to be clear.
It is about 1/4th~1/3rd the size of the Volvo windshieldwiper pump I was using in the experiments.
As for performance: The Windshieldwiper pump would not run a lower voltage than 2S NiMH (under load maybe 2,3V), draw 900 mA when actually pumping (which is 2,1W of power absorption) and would deliver about 300 ml/min against the backpressure of the condenser coil.
The condenser NEEDS only 100 ml/min, but is not critical for a bit excess water.
This tiny thing runs well on 5V, and then draws 180 ml at open delivery, pumping about 1L/min, but against the backpressure of the condenser drops to about 200 ml/min and a currnt draw of about 170 mA. That's only 0,85W, and low enough for to allow direct power from the receiver busbar.
Now relocating the overboard discharge to above the waterline for visual confirmation of function (centrifugal pumps do not always self-prime), and installing the pump under the floorplate, and Ravika Putri will look again as if nothing happened...
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(https://www.modelbouwforum.nl/attachments/20240504_001000-1-jpg.581910/)
Pump glued in on a wooden spacer. Spacer holds 8 magnets 3 x 6 mm in a circular pattern.
(https://www.modelbouwforum.nl/attachments/20240504_001014-1-jpg.581911/)
Suction opening needs to be made flush with the hull.
The magnets in the pump base serve to hold a strainer over the suction opening in place. Strainer to be made of tin sheet and steel wire.
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Meanwhile....
Things slowed down a bit due to an episode with BPPD knocking me out for a while, and the gradual return to work.
Meanwhile, I finished the condenser cooling set-up. In the last post, the pump was installed and it stopped there.
Thinks left to do were hooking up the pump directly to the stabilized 5V servo busbar by means of a JR servo connector.
That makes the pump run continuously, but it only draws about 110 mA dry and about 175 mA submerged.
Submerged, the pump is inaudible and delivers about 250 ml/minute, which results in a delta-T over the condenser of about 35 deg C at full steam, and an absolute full condensing of any and all exhaust steam.
Because the boat is going to be used in open water, an intake strainer is advisable. I made that one out of an M12 steel washer, 8 short pieces of 1 mm round wire and a bit of Epoxy.
(https://www.modelbouwforum.nl/attachments/20240603_001110-1-jpg.584392/)
The 8 magnets I incorporated in the pump base hold the strainer in place, and make removal for cleaning easy
(https://www.modelbouwforum.nl/attachments/20240603_001055-1-jpg.584391/)
The original optics of the boat have been fully restored with the exception of the visible water supply and discharge tubing
(https://www.modelbouwforum.nl/attachments/20240602_230934-1-jpg.584389/)
Water discharge is overboard above the waterline, for visual confirmation of full flow/detection of clogged strainer
(https://www.modelbouwforum.nl/attachments/20240602_230946-1-jpg.584390/)
I think I have mentioned it before somewhere, but this basically means that the installation is complete. Maybe some cosmetic work in the future, but technically, I can't think of anything else to add. Maybe one day I will rearrange the slop-discharge such that the oily water and feedwater tanks will be relocated to the doule bottom. That would unclutter the engine space a bit. But to be honest, that would be a lot of work for things I do not really care about.
As it is, the system now consumes less than 100 ml of water per hour of running, and it can stay out on the water for that hour, WRT fuel, water and slop capacity.
It has been good fun!
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Bonjour Brutus,Great job indeed but I have a question, where is the whistle ok2 ?
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Bonjour Brutus,Great job indeed but I have a question, where is the whistle ok2 ?
:D :D :D I think I posted my opinion on whistles... waste of precious steam :D :D :D
Just kidding a bit... But no... for one reason or another, whistles do not appeal to me.
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Bonjour,
https://youtu.be/k9cC0AUeuxM ok2
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I like to silently sneak up from behind the horizon... %%
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In general a word of warning about the Microcosm:
The safety valve has a steel ball as the sealing element.
This ball is NOT made of Stainless Steel in mine, with as result that it rotted stuck and did not open even at over 6 bar... (setpoint when I commissioned the boiler was 3,5 bar, never touched the setting afterwards).
Be aware!
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Meanwhile I found this: https://www.bengs-modellbau.de/en/Grafi-sil-valve-balls/12799 and that should solve the issue permanently.
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Meanwhile I found this: https://www.bengs-modellbau.de/en/Grafi-sil-valve-balls/12799 (https://www.bengs-modellbau.de/en/Grafi-sil-valve-balls/12799) and that should solve the issue permanently.
Balls have arrived, first try is promising: Safety valve seals properly at working pressuree, and unmistakibly "pops" at set pressure.
There is a slight hiss from about 0,5 bar below set pressure, but I can live with that, since my operating pressure is set at 1,5 bar and the set value of the safety is 4 bar.
All I need to know is that the valve seals properly at working pressure and opens reliably when needed. And since this material cannot corrode, it can't get stuck so that should be OK.
EDIT: took out the ball after the first test, where I let the safety blow continuous for about a minute, and I saw zero deformation or damage to the ball-valve.
Steamed for 1 hour, which passed with zero leakage from the valve, and took the ball out again. Still zero deformation.
I am currently using the 5 mm ball, which is same size as the original steel ball.
I ordered additionally a 6 mm ball, which should result in a bit more of a "high lift" characteristics. Will test that too, to see if there is a difference in opening and closing behaviour.
But so far, I am absolutely convinced that Grafi-Sil balls are a safe option for use as safety valve in low pressure boilers (opening pressure 4 bar).
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Bonjour,
Just for information, most of my safety valves are like these ones : https://youtu.be/if7rpSANj7g (https://youtu.be/if7rpSANj7g)
However, I have also successfully tested a more than 100 years old one : https://youtu.be/W7pxeN_leUk (https://youtu.be/W7pxeN_leUk)
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Good info! One of these days I will make a vid detailing the Microcosm valve.
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Meanwhile, I noticed something I did not really like...
The pond that my boating club uses, has pretty dirty water. Normally after an evening of boating, there is a pretty dark brown smudge on the hull around the waterline.
Ravika Putri now has about 6 or 7 hours of steaming with the functioning cooling water pump, and it has been working pretty much flawless, but non of that runtime was done on the club pond, until this evening.
I launched the boat, and after about 10~15 minutes I saw a whiff of steam from the condenser at full speed. Brining the boat in, the cooling water flow had reduced to a trickle. I checked the intake strainer and it was clean. So it has all appearance the condenser coil clogs up.
I could blow it through, restoring the flow again, and the remainder of the fuel the waterflow remained acceptable but reduced visibly.
So... water quality apparently also has an effect if heat load is significant... It fouls the cooling surfaces. I really did not expect it to be that noticable...
EDIT: Apparently, the particular dirt in that pondwater is pretty water soluable... I put the boat in the Lab test basin (AKA my bathtub :D ) and to my surprise the restricted flow restored itself in about 2 or 3 minutes of flushing. The pump slowly dropped in RPM, while the flow simultaneously slowly increased. I did not see any visible dirt come out.
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I launched the boat, and after about 10~15 minutes I saw a whiff of steam from the condenser at full speed. Brining the boat in, the cooling water flow had reduced to a trickle. I checked the intake strainer and it was clean. So it has all appearance the condenser coil clogs up.
I could blow it through, restoring the flow again, and the remainder of the fuel the waterflow remained acceptable but reduced visibly.
So... water quality apparently also has an effect if heat load is significant... It fouls the cooling surfaces. I really did not expect it to be that noticable...
EDIT: Apparently, the particular dirt in that pondwater is pretty water soluable... I put the boat in the Lab test basin (AKA my bathtub :D ) and to my surprise the restricted flow restored itself in about 2 or 3 minutes of flushing. The pump slowly dropped in RPM, while the flow simultaneously slowly increased. I did not see any visible dirt come out.
1,5 month later, I can report that this phenomenon ("clogging" of the condenser) has not returned, in several hours of steaming, both on the club pond or other places.
Water consumption has DRASTICALLY reduced from 3/4 of a litre to about 100 ml tops per outing. I haven't had to use the distiller plant for ages now.
So far, I do not see any signs of the boiler fouling, or other malfunctions due to the re-use of condenser effluent for feedwater.
Although I try to maintain the habit of bringing in the boat every 15 minutes or so for a quick check of boiler and feedwater level, but basically the installation has become quite literally a matter of "fire up and forget".
The very simple variable timer linked to the steam valve has proven rather accurate and reliable: the other day I sent the boat out with the usual 60 grammes of fuel, and went about fairly conservative with the steam valve, and the result was about 2,5 grammes remaining when the counter hit zero, after a 1 hr 10 minute run.
The Grafi-Sil valve does an excellent job as a safety valve, entirely leak-free.
EDIT: Engine and boiler runtime is now nearing 77 hrs. Which roughly means that 4,6 kilograms of fuel have passed the burner, roughly 77 kilogrammes of steam have been generated, and the current feedpump with its modified Futaba S9254 servo has now about 27 operating hours (the original Regner servo only lasted about 5 hrs). About 120 ml of cylinder oil, and maybe 60~70 ml of engine oil have been consumed...
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Well done on a great piece of steam engineering and for the detailed updates, from which I have learned a lot, so thank you
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Well done on a great piece of steam engineering and for the detailed updates, from which I have learned a lot, so thank you
You are very welcome!
Hope to see your results one day.
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Meanwhile, the boat gradually started to produce more and moref noise when running ahead, which I expected to come from either the crossheads or the Stephenson arcs: crossheads are asymetrically loaded, the arcs are most of the time in one position, so those were my first suspects.
It did not surprise me (it's a "cheap chinese" engine after all) but it worried me a bit, because my possibilities for overhaul/repair of the engine are limited
Today I took a soundrod went over the entire installation, listening to tocs, rattles and other noises.
Great relief to find that the noise is somewhere in the universal couplings or the propshaft, the engine is running as smooth as silk WRT mechanical noises. No measurable wear on the arcs, no detectable lateral clearance in the crossheads or guides, no sloppy conrods, no audible difference between fwd and aft cylinder. Not bad for close to 80 runhours in less than 14 months. Wick-feed lubrication, I can recommend it! :D
But jeez... Now the task of figuring out where that noise comes from... {:-{
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Glad to hear the engines is fine, and no signs of wear, thats really good. Hopefully the noise will be an easy fix by lubing the propshaft or swapping the joint - you could try using some silicone tube instead of the universal coupling to see if the UJ is the problem.
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Glad to hear the engines is fine, and no signs of wear, thats really good. Hopefully the noise will be an easy fix by lubing the propshaft or swapping the joint - you could try using some silicone tube instead of the universal coupling to see if the UJ is the problem.
Yeah, that was a big relief...
I don't know yet what is the issue with the shaft arrangement. The universal joints have been enclosed with silicone tubing, and filled with grease, so I would expect them to be quiet.
Trouble is that I can't run the engine with the boat opened up, so it's hard to figure out what the trouble will be.
But one day, I'm sure I will be able to fix it... :D
EDIT: I just THOUGHT I had those joints enclosed and filled with grease, but... I didn't. Now that was an easy troubleshoot and an easy fix...
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Meanwhile...
Due to work and other stuff (weekly change from nightshift to day for 8 weeks wreaks havoc on a persons desire to tinker) the boat has been shelved for 2 months, but today was a nice day. With only a simple charge of the RX batt and a fill of the feedwater tank and the wickfeed oiler and no other checks, the boat was launched, steam was raised and off she went...
70 minutes of full autonomic operation later the "fuel counter" (variable timer that runs faster or slower with the throttle) indicated that the gas tank would be empty soon, which indeed was the case within 5 minutes after that.
Gas consumption 65 grammes, water consumption about 50 ml (all of which contained in the oily water receptacle), and a constant boiler level.
Fuel tank heating kept the tank at a nice 19~20 degC (it was about 11 deg C outside) so sufficient fuel pressure from full to empty.
Runtime counter is at 82 hrs 40 minutes now, I guess she's fully broken in by now :D
Basically "as reliable and simple to operate as an electric" but much more fun :D
There should b some videos, if I can get them, I'll upload to YT and post.
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There should b some videos, if I can get them, I'll upload to YT and post.
https://www.youtube.com/watch?v=KV3ScOJ5ILI
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These engines are way more durable than their reputation (in other forums they are at times put down as "cheap chinese crap"), because with, as far as the engine itself is concerned, ONLY the things done as described in post #5 (which were if anything, rectifications of QC issues rather than "repairs") the engine has done a whopping 90 running hours since its first run on June 6th 2023, 90 hours with zero malfunctions on the mechanical parts, and zero noticable wear or deterioration.
It's a shame they seem to be out of production.
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Bonjour,
I have a M29 steam engine : https://youtu.be/TO16806-3pM (https://youtu.be/TO16806-3pM) which goes on existing but with accessories (flyball, pump). which is similar to yours.
What would you think of this one : https://youtu.be/NDDoZdUhszY (https://youtu.be/NDDoZdUhszY) ?
https://www.okmomodel.com/okmo-mini-retro-vertical-double-cylinder-reciprocating-double-acting-steam-engine-model-toys-with-speed-reducerm30m30b-p5456987.html (https://www.okmomodel.com/okmo-mini-retro-vertical-double-cylinder-reciprocating-double-acting-steam-engine-model-toys-with-speed-reducerm30m30b-p5456987.html)
I don't use my machines a lot and have had yet no issue at all with them. Jin sent me a water level to replace the one broken when delivered without any question :-))
My only concern would be that I find that his prices are no longer "cheap" and almost similar to the ones of my French manufacturer https://www.jmc-vapeur.fr/ (https://www.jmc-vapeur.fr/) with whom it is very easy to share.
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My only concern would be that I find that his prices are no longer "cheap" and almost similar to the ones of my French manufacturer https://www.jmc-vapeur.fr/ (https://www.jmc-vapeur.fr/) with whom it is very easy to share.
Chinese can deliver quality, but like everything in life, for quality you pay more. So far, with only the minor ans easily solved issue of in my case the slidervalves, if I compare the M30 which costs 500 dollar, with the closest Regner machine, which would IMHO be the Letho 2 LETO 2 Zylinder Dampfmaschine | REGNER (https://www.regner-dampftechnik.com/product-page/leto-2-zylinder-dampfmaschine), then I'd say the Microcosm is only 60% of the price while looking a fair bit prettier... The Regner, IMHO, LOOKS "cheap" (albeit absolutely well made, external appearance looks like corners were cut in order to keep price reasonable).But I do not know the prices (or looks, or quality) of French steam engines...
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Bonjour,
The Netherlands are not so far from France ok2
I hope these examples will give you the envy to watch his site and I would like to point out that I am not a JMC reseller :}
Example of 1 cm3: https://youtu.be/x_lv2uXhsto (https://youtu.be/x_lv2uXhsto)
Example of 2 cm3 steam plant : https://youtu.be/wJym95xNLf8 (https://youtu.be/wJym95xNLf8)
Example of 3 cm3 : https://youtu.be/6drdmVgoJFQ (https://youtu.be/6drdmVgoJFQ)
Example of 5 cm3 : https://youtu.be/JBwO-jLAfnI (https://youtu.be/JBwO-jLAfnI)
Example of 7,5 cm3 steam plant : https://youtu.be/qk74P2k8W2o (https://youtu.be/qk74P2k8W2o)
Example of 8 cm3 steam plant : https://youtu.be/NOIW4ucypXw (https://youtu.be/NOIW4ucypXw)
Example of 8,5 cm3 with pump : https://youtu.be/TnNkqDPZnWw (https://youtu.be/TnNkqDPZnWw)
Example of compound : https://youtu.be/8tpREH2SVi0 (https://youtu.be/8tpREH2SVi0)
Example of gas regulators : https://youtu.be/V8ybmqgcNak (https://youtu.be/V8ybmqgcNak)
Example of donkey pump (petit cheval) : https://youtu.be/hSwG2p45iGY (https://youtu.be/hSwG2p45iGY)
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I have to admit, those are really beautiful engines... They look nothing like Regner, they absolutely have the same style as Jin's engines.
Still a fair bit more expensive than Microcosm, but not prohibitively more expensive, I have to admit that.
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The difference between both :
- If you have a problem with a JMC engine , you can fix it , get repaired or have spare parts.
With Microcosm , you change the complete engine. Not easy to fix whenever you can open it.
Some friends came to me with their plants because they could not perform as they thought >>> engine oversized with the boiler or vice versa.
I think that I have one of these engines... somewhere in my mess ... ok2 :o
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I can't confirm or deny.
As far as I can tell, the Microcosm also just comes apart when you turn the bolts counterclockwise, just like any other machine I've worked on...
Ordering parts might be an issue with Jin, then again, I don't really think I'm going to need any.
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Bonjour,
Far be it from me to oppose one manufacturer to another, I just wanted to show that there is at least one alternative to Regner which has changed owner/manager in Europe.
If you have read this topic, you will notice that JMC helped me twice within a week :
https://www.officeofsteamforum.com/technical-tips-builds-and-help/empty-your-boilers-after-use!/ (https://www.officeofsteamforum.com/technical-tips-builds-and-help/empty-your-boilers-after-use!/) :-))
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Meanwhile...
in this thread: https://www.modelboatmayhem.co.uk/forum/index.php/topic,70510.0.html (https://www.modelboatmayhem.co.uk/forum/index.php/topic,70510.0.html) I described the modification from gas phase feed to liquid phase feed.
This mod allowed more fuel to the boiler, and since back then when the steamplant was initially commissioned, the throttle valve was basically adjusted to what the burner could deliver, it stood to reason that this adjustment also was reviewed.
Alas, more fire, more steam to the engine, what is not to like?
Well, this: it turned out that the oil separator, which could keep up in the previous situation, now could not anymore. Oil passed the separator and ended up in the condensat return. Dammit!
(https://www.modelbouwforum.nl/attachments/img-20241209-wa0016-1-jpg.602671/)
This beautiful piece of equipment is the oil separator. It is a very simple drum, with exhaust steam inlet, and clean steam outlet on the top. The idea is that oil and emulsified droplets of condensate fall to the bottom, and clean steam escapes. Right side is dirty steam in, left side is the clean steam out. In the background the riserpipe that discharges the collected crud.
Back before the mod, this would work until full throttle, and after the mod, it still worked flawless up to about 75% throttle (basically equivalent to the pre-mod full throttle).
What was happening? The only thing I could think of, was that higher throughput, would also increase the velocity of the dirty steam into the separator.
This steam is jetting vertically downwards, and down there at the bottom is a puddle of crud. Increased velocity could mean that the incoming steam would whip that puddle into a froth, throwing droplets around, and thse droplets could then be "sucked up" by the equally increased velocity with which the (now not so) clean steam leaves the separator.
My solution:
(https://www.modelbouwforum.nl/attachments/img-20241209-wa0017-1-jpeg.602672/)
I soldered a 5 mm ID tube at the bottom of the inlet connection. This tube has an open end, but is measured to exactly end up at the bottom of the separator vessel, so practically, this end is closed off. Mind you, NOT "sealed off", meaning any liquid (oil or emulsified water) inside that inlet diverter pipe can flow out through the seams, but steam won't blow into the puddle of crud and whip it up.
In the side, 5 holes 2 mm crossection are drilled, and they are indexed such that the steam in the separatorvessel gets a counterclockwise rotation. This rotation should help any droplet of liquid to find the outer wall, cling to it and flow down. The 5 holes should be sufficient to reduce steam velocity, in order to reduce/eliminate any possible frothing.
So now we have a (relatively slowly) rotating body of steam in the separator vessel, centrifuging out any droplets, the liquid flinging to the wall and flowing down, clean and moisture free steam rising to the top of the vessel and escaping to the condenser. Or at least, that is the expectation.
I fired up the boiler, and once hot, set the throttle to full speed and left it running for a full tank of fuel.
What I noticed was that initially there was a bit of turbidity of the condensate (which of course was not the funniest of observations, to put it mildly), but this seemed to clear within 5 minutes. I think I was looking at "old oil" in the condenser left there by previous sessions.
Also, I had the clear impression that the amount of liquid discharged by the separator was less than usual, and also the properties of that effluent had changed: it was oil and water like before, but previously, that water was very strongly emulsified, now it appeared much clearer. I cannot explain the reduction in volume, but I think the reduced emulsifying is due to the reduction in velocities inside the separator vessel.
All in all, I'm happy...
I've got more power, and I can practically use it now too.
EDIT: final report, I checked the water in the Hotwell, and found an ever so slight turbidity, barely visible. I think this was residual from the dirty shot of water in the first 5 minutes, and should not return anymore. It was anyway so minor that I don't think this will cause any problems.
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Great report, thank you for sharing your continued development of your steam plant, there is a lot there for us all to learn from and adapt for our own steam plants.
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I really hope it helps people to think outside the box.
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Because single tests never are conclusive, I tested again this morning...
Conditions:
Boiler water as left in the boiler yesterday.
Hotwell emptied and refilled with destilled water 2 ppm TDS
65 grammes of gas, should allow for 34 minutes of wide open runtime after raising steam.
During this time, the contents of the hotwell are pumped in full approx 3 times through the boiler, meaning that the entire hotwell after the test is condnsate, no original destilled water present anymore.
Started, ran until low fuel alarm, and checked the hotwell contents afterwards:
(https://www.modelbouwforum.nl/attachments/img-20241210-wa0012-1-jpg.602713/)
Water is as clear as can be.
Tested the water:
(https://www.modelbouwforum.nl/attachments/img-20241210-wa0013-1-jpeg.602714/)
Previous to the fuel mod and resulting increase in power, this value usually was between 6 and 8 ppm after a full run, results varying a bit with how much full ahead was used.
The reduction in separator effluent, as well as its change in appearance, seems to be consistent, which leads me to review my previous belief that the emulsion and condensation was formed in the engine (my assumption was that heatloss in the engine, as well as the steam delivering power to the pistons would cause some condensation, and the mechanical action of wildly moving pistons would create the emulsion).
It seems, that the conditions previously in the separator were cause of at least in part, the formation of emulsion, as well as increase in condensation.
I think the high velocity steam hitting a static liquid surface caused both strong emulsification as well as additional condensation.
I would have to measure more precise, but I have the feeling that the hotwell is dropping less in level than previously, which would mean that ther is ACTUALLY less condensation going on, and the difference is being passed on to the condenser.
This also made me take a look in the separator after the test. I cannot take pics through a 7 mm hole, but what I saw amazed me, literally, and I am not that quickly amazed: Where in the past, at the end of a run there would be some oily crud left in the separator, now I saw a squeaky clean vessel, the bottom oil free and mainly dry with a few droplets of water here and there.
Goes to show, that a LOT can be improved on conventional condenser/oilseparator equipment, with only minor modification work.
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Runtime counter is at 82 hrs 40 minutes now, I guess she's fully broken in by now :D
Daaaang....
Yesterday passed 102 runhours... 20 hrs in 1,5 month...
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You might already have the highest run time of any steam boat on this forum :-)
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You might already have the highest run time of any steam boat on this forum :-)
Currently just over 107 hrs...
Maybe people think I am a bit weird for paying very close attention to feedwater quality, maybe laugh a little bit about all the fuzz I make about it.
But the system starts and runs like the day it was new, and so far literally zero mechanical or technical problems.
I like it that way.
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The other projects seem to have a slight supressive effect on the gathering of runhours, only appr. 7 since last post (113hr45min).
Yesterday at SMG IJmond (beautiful pond and "harbour") it was extremely hot and sunny, 32 deg, water temp not measured but above 20 deg on the surface.
Because of that, and my fuel tank being black and thus picking up radiation from both engine and the sun, tank temp kept rising, so I kept sessions limited to about 40 deg C tank temperature.
Other than that, it really gets boring, the steamplant functioned flawlessly... Sigh....
(https://www.modelbouwforum.nl/attachments/20250621_114003-jpg.621782/)
(pic: Ronald Post)
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The picture doesn't load.
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The picture doesn't load.
Strange... I can see it here...
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Strange... I can see it here...
+1