Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: 1967Brutus on October 28, 2023, 10:02:23 am
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The category states "Electric, glow, steam, diesel", but this is going to be gasoline...
About 7 years ago, as a side project, I modified an ASP fourstroke glow engine to run on gasoline, run an extremely low RPM (it had no issues going elow 1000 RPM, but I ended up with 1500 RPM, governed, in order to have some velocity at the prop blade tips) and I temporarily fitted that in the cheapest hull I could find.
It was a fun project to get that little engine running halfway decent (there still is some work to be done with the valve timing, other than that it ran fairly OK), and the plans were there to transfer the whole set-up to a decent boat once everything was running OK.
Unfortunately that never materialized until now.
That boat had a CPP, and a steering Kort-nozzle and that, as we probably all know, results in remarkable manouvering characteristics.
https://www.youtube.com/watch?v=fNxp-d6AfxA
Fuel consumption was ridiculous, at 20 ml per hour approximately...
Anyway, the build of the new hull for this plant has now started. No idea when it will be finished, because since I have a bit more room, I intend to add on-board starting, and change the engine from aircooled (temperature controlled electric fan) to watercooled (closed loop with bilge-cooling, probably engine driven pump).
Now I am not the most organized builder, but:
(https://www.modelbouwforum.nl/attachments/20231028_102244-1-jpg.558475/)
(https://www.modelbouwforum.nl/attachments/20231028_102252-1-jpg.558476/)
means that the continuation of this slow speed gasoline project has finally found continuation after 7 years...
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So far, pretty straight forward building...
Deck in place:
(https://www.modelbouwforum.nl/attachments/20231028_191109-1-jpg.558528/)
The "backbone" adapted to accept the Marx controllable pitch propeller and shaft:
(https://www.modelbouwforum.nl/attachments/20231028_232724-1-jpg.558558/)
Test-fitting the shaft on the backbone:
(https://www.modelbouwforum.nl/attachments/20231028_232737-1-jpg.558559/)
And the backbone glued in the hull.
(https://www.modelbouwforum.nl/attachments/20231028_235505-1-jpg.558560/)
It is getting late, so tomorrow continueing with fitting the propshaft in the hull.
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Giving the build another kick, today worked out the hole in the hull to pass the sterntube through:
(https://www.modelbouwforum.nl/attachments/20231029_160925-1-jpg.558881/)
The sterntube assembly was located, marked and glued in
(https://www.modelbouwforum.nl/attachments/20231029_165343-1-jpg.558883/)
This is the first sign of "something is going to be different about this"...
and fixated:
(https://www.modelbouwforum.nl/attachments/20231029_165322-1-jpg.558882/)
Glue used is Bison Combi Power PolyUrethane 2-component. I was told this to be the best option for ABS after Stabilit-Express (which is not easily availlable over here), but I am not too happy with this glue WRT handling. Stabilit is easier to get a nice and smooth result with
I'll have to wait for the glue to set before fitting and placing the fin.
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So... I glued the sterntube in, as centered and parallel as I could, basing myself on the "backbone" (which due to the laser-cut and symetrical frames SHOULD be centered and parallel, right?)
Well... when I placed the fin, it turned out that the inside of the hull does not 100% align with the outside... What is centered on the inside, turns out to be about 1 mm sideways of the center of the outside,,,
(https://www.modelbouwforum.nl/attachments/20231029_183607-1-jpg.558915/)
(note how the fin lines up with the keel of the hull)
But other than that, things seem to work out fine
(https://www.modelbouwforum.nl/attachments/20231029_195135-1-jpg.558917/)
(https://www.modelbouwforum.nl/attachments/20231029_195230-1-jpg.558918/)
Basically, here is where I have to start deviating from what the kit instructions say the order of assembly should be, because from now on I need to take the driveline into account, and that driveline does not only not yet exist, it also will most definitely NOT match the lay-out of the originally intended steam plant.
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So... today the rudder construction was tackled.
Fitted the heel to the fin, aligned the rudderstock to determine the spot for drilling, and so I did.
Looks nice and vertical:
(https://www.modelbouwforum.nl/attachments/20231030_124214-1-jpg.558956/)
Looks nice and centered:
(https://www.modelbouwforum.nl/attachments/20231030_124223-1-jpg.558957/)
And then you look on the inside and:
(https://www.modelbouwforum.nl/attachments/20231030_124235-1-jpg.558958/)
Not in the middle... :( and I have no idea where this went wrong.
What I also don't like: THat deck frame is there according to drawing.
The rudder bearing tube is there according to drawing.
The servo mount is according to drawing, and still, that deckframe blocks virtually all portside rudder deflection, and the pushrod cannot be installed due to the frame being in the way.
The looks and style of this boat is pretty, the contents of the kit are decent if not downright good, but the design and execution are a bit poor to say the least...
Oh well...
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Rudder done...
(https://www.modelbouwforum.nl/attachments/20231030_173347-1-jpg.559020/)
(https://www.modelbouwforum.nl/attachments/20231030_173508-1-jpg.559021/)
Of course the rudder will get a coat of paint, prolly a proper "antifouling-red" colour (no real antifouling of course, just the colour...
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I was a bit not paying attention when I cooked up this:
(https://www.modelbouwforum.nl/attachments/20231030_221328-1-jpg.559074/)
Then I looked in the drawings, and there's supposed to be a floor there, right at the level where the pitch servo sits...
So too ridiculous for words to have a separate bracket. Thus:
(https://www.modelbouwforum.nl/attachments/20231030_232258-1-jpg.559075/)
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But with a little it luck it will be barely visible once the salon is done:
(https://www.modelbouwforum.nl/attachments/20231031_090357-1-jpg.559093/)
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An this is where the "but... different..." really kicks in :D
The saloon is at the moment only loose wooden parts loosely put in place to assess what needs to be changed, since from here on I cannot follow the building instructions anymore and have to make my own.
(https://www.modelbouwforum.nl/attachments/20231031_162822-1-jpg.559137/)
looks like I can still permanently fix the floor in place, if I enlarge the cut-out a few mm more so I can reach the rear grubscrew of the cardanic coupler.
Within 1 or 2 cm, this should be the location of the engine if I want to keep the angle differences between the three shafts within reasonable limits.
Since with the Marx variable prop, the entire shaft moves forward/aft when the pitch is changed (total movement approx 3~4 mm) the rear couping is cardanic (Robbe Nickel plated Brass item) but the forward coupler HAS to be a dogbone coupler to allow for this displacement. That one is a Raboesch item. Brilliant stuff, that, because I could get them even in the same thread as the size used on the crankschaft, so that is a direct bolt on.
(https://www.modelbouwforum.nl/attachments/20231031_162831-1-jpg.559138/)
And... I am "starting to séé it"...
(https://www.modelbouwforum.nl/attachments/20231031_162839-1-jpg.559139/)
Of course, the flotsam currently still attached to the engine needs to be discarded and a decent engine foundation needs to be built.
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So today I had to do something about the engine, or at least, how to mount it in the boat.
Some scrap wood, an electric jigsaw, and some Aliphatic glue, and...
(https://www.modelbouwforum.nl/attachments/20231101_151235-1-jpg.559308/)
(https://www.modelbouwforum.nl/attachments/20231101_181324-1-jpg.559320/)
(https://www.modelbouwforum.nl/attachments/20231101_181330-1-jpg.559322/)
The stand is much larger than necessary to support the engine, but I needed the platform on the bow-side in order to mount the throttle servo, and I needed the beams to extend aft in order to fit the RPM pick-up that supplies the governor with info.
(https://www.modelbouwforum.nl/attachments/20231101_182535-1-jpg.559326/)
(https://www.modelbouwforum.nl/attachments/20231101_182543-1-jpg.559329/)
Now everything has to come apart again for oil and fuel proofing, so tomorrow will be pore-filler day, day after will be paint/laquer day, and Saturday I can check hull integrity...
And from there on, I can start following the kit's building instructions again.
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And from there on, I can start following the kit's building instructions again.
But until then:
Machine deck has been sealed against water and oil and is now "uniting" with the hull
(https://www.modelbouwforum.nl/attachments/20231102_194653-1-jpg.559500/)
The old batteries serve as weight to pin down until the glue has cured
Engine foundation is fitted with the throttle servo and also sealed up:
(https://www.modelbouwforum.nl/attachments/20231102_194721-1-jpg.559501/)
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First float test, not bad at all... I had a slight fear it would be down by the head (the engine + flywheel weigh in at 1,4 kilo), but surprisingly trim turns out to be even slightly down by the stern.
(https://www.modelbouwforum.nl/attachments/20231103_014950-1-jpg.559539/)
Still lots of wood and glue to go, and a fair bit of installing and commissioning...
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Today I reworked the camshaft of the engine a bit, to get the exhaust to open approx 15 degrees before bottom dead center (was something like 60 degrees) and close again as close as possible to TDC (was about 40 degrees after IIRC).
Ditto but opposite deac centers for the intake valve.
This, because valve timing calculated vor 10K RPM simply is not suitable for 1,5K: Especially severe reversal of exhaust gas as a consequence:
Intake opens 40~50 degrees before TDC, but exhaust closes 40~50 degrees after TDC. After TDC, piston goes down of course, but throttle opening is extremely small, and since there's no restriction in the exhaust, spent gas is being drawn in instead of fresh mixture, until the exhaust closes. This "dilutes" the fresh mixture which results in poor combustion and fouling engine.
I do not have pictures of that.
I did the regrinding of the cam profile freehand with a grey stone in the Dremel. Only tiny bits of removal needed. Given the extremely small throttle opening (approx 1~1,5 mm2 or maybe less) and the low engine speed, it is safe to say that cam profile, seat hammering and maximum valve lift become totally irrelevant. Only timing matters.
Aside from that, "collision bulkhead" was made, fitted, pore-fillered and laquered.
(https://www.modelbouwforum.nl/attachments/20231103_172504-1-jpg.559614/)
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Bulk head installed:
https://www.modelbouwforum.nl/attachments/20231103_214918-1-jpg.559645/
https://www.modelbouwforum.nl/attachments/20231103_214901-1-jpg.559646/
(https://www.modelbouwforum.nl/attachments/20231103_214901-1-jpg.559646/)
(https://www.modelbouwforum.nl/attachments/20231103_214918-1-jpg.559645/)
Pretty happy with the result. I am normally not a "pretty" builder, but this looks acceptable to me.
Installing the ignition (which by the way, is a CH ignitions item with a customized advancing curve that retards all the way down to 0 RPM instead of only down to 1000 RPM)
(https://www.modelbouwforum.nl/attachments/20231103_220044-1-jpg.559650/)
After a lot of fiddling (narrow access, everything has to be done with max 2 fingers) the ignition is into place and packed in foam rubber
(https://www.modelbouwforum.nl/attachments/20231103_220500-1-jpg.559655/)
Looks nice to me:
(https://www.modelbouwforum.nl/attachments/20231103_220520-1-jpg.559656/)
Installing is near impossible with the engine in place, so that has to be installed back as well
https://www.modelbouwforum.nl/attachments/20231103_222544-1-jpg.559657/
(https://www.modelbouwforum.nl/attachments/20231103_222544-1-jpg.559657/)
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Getting closer and closer...
https://www.modelbouwforum.nl/attachments/20231104_150027-1-jpg.559757/
https://www.modelbouwforum.nl/attachments/20231104_150036-1-jpg.559758/
I hate that sheeting of the deck, but to be honest, the declining ugliness works motivating...
(https://www.modelbouwforum.nl/attachments/20231104_150027-1-jpg.559757/)
(https://www.modelbouwforum.nl/attachments/20231104_150036-1-jpg.559758/)
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The structural build is nearing its end:
Cabin is glued in place, the door is hinged (unlike the builder :D)
https://www.modelbouwforum.nl/attachments/20231105_155628-1-jpg.559951/
Interior is largely done (only steering stand still to be done)
https://www.modelbouwforum.nl/attachments/20231105_155637-1-jpg.559950/
Roof is removable for access, and so are the benches and table
https://www.modelbouwforum.nl/attachments/20231105_155651-1-jpg.559941/
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Today I did not feel like woodwork, so I made the fuel tank, from brass tubing brazed with silver.
I can make a pretty brazing but then it won't be a good (tight) one, or I can make a solid and tight brazing but then it won't be a pretty one.
the end caps are just flat Brass sheetmetal pieces, brazed square to the ends and after brazing cut to shape with a normal household scissors (the stuff gets pretty pliable after brazing).
For my skill level, this ain't too bad:
https://www.modelbouwforum.nl/attachments/20231106_094405-1-jpg.560042/
I cleaned the flux off in the U-son, using hot water, a splash of Dasty, and a tablespoon of Citric Acid:
https://www.modelbouwforum.nl/attachments/20231106_103303-1-jpg.560043/
Came out fairly clean
https://www.modelbouwforum.nl/attachments/20231106_104704-1-jpg.560044/
but a bit of brass polish made it shine even better (which still is not "showroom quality", but acceptable).
Location in the boat, about here:
https://www.modelbouwforum.nl/attachments/20231106_104721-1-jpg.560045/
Brackets made out of wood, currently curing.
Exhaust system going to be made in a similar way.
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And... She's ALIVE!
https://www.youtube.com/watch?v=7XhK0M-AmJg
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Ballast was done with loose bricks (literally) making CoG too high and the boat a bit tender because of it.
Then the rolling makes the bathwater slosh, which amplifies the rolling...
But here's a first test with the RC gear thrown in loosely and the governor installed and active.
https://www.youtube.com/watch?v=ufhKXAC50d8
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I cleaned the flux off in the U-son, using hot water, a splash of Dasty, and a tablespoon of Citric Acid:
I highly underestimated the tenacity of that flux, first run, after being done and emptying the tank, I noticed the fuel having lost all its colour (it normally is bright red because of the oil I am using).
Meaning I ran acidic fuel through the engine. Not good.
Ran the engine for 10 minutes from another not contaminated tank, and boiled out the original tank for 30 minutes in water with laundry detergent (alkaline, should neutralize acids).
Next boiled it out in straight tapwater for another half hour.
Ran the engine today, and afterwards still saw a minor bit of discoloration, not as much as before, so I guess it is acceptable now but that was not a good thing of me, to run the engine with an improperly cleaned tank...
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It seems to work...
Put ballast in the sides, approximately on the waterline in order to increase inertia but not increase stability (higher stability makes the boat roll back and forth more violently which also is not desirable), and this seems to have a calming effect on things. Still rolling, but not as wild anymore.
Made some adjustments to the governor, also having a positive effect on throttle response
https://www.youtube.com/watch?v=t8S6NmNbQz4
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Bert...with you as a seagoing Marine Engineer, I would not ever contemplate to question your comments about ships stability :P , however if you could use lead Shot [from a GunSmith Store] and sprinkled it at the lowest point available within the hull would it not lower the metacentric point of balance?
This then like a lower pendulum, will decrease the frequency of the roll, but increase the extreme angle of roll?
So we see your Alexandra in the bath.......& the rock & roll generated as frightening, so to consider all things being equal in an open water with a little gust breeze, she may do a 180 or capsize :embarrassed:
Another option would be to use whatever lead you currently have as ballast, and cast an external keel bulb ..............but that would look pretty stupid
Derek
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Looks amazing, it’s lovely to see a new build scale boat with a proper engine in it
Don’t think you’ll ever stop the torque roll you’re getting from that gigantic flywheel - I’ve seen smaller on full size boats ;)
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Bert...with you as a seagoing Marine Engineer, I would not ever contemplate to question your comments about ships stability :P , however if you could use lead Shot [from a GunSmith Store] and sprinkled it at the lowest point available within the hull would it not lower the metacentric point of balance?
This then like a lower pendulum, will decrease the frequency of the roll, but increase the extreme angle of roll?
So we see your Alexandra in the bath.......& the rock & roll generated as frightening, so to consider all things being equal in an open water with a little gust breeze, she may do a 180 or capsize :embarrassed:
Another option would be to use whatever lead you currently have as ballast, and cast an external keel bulb ..............but that would look pretty stupid
Derek
Nah... I am not that worried for a capsize or something like that... Maybe when the engine would seize, she could dip her boards, but even then I don't expect her to keel over.
First of all, don't forget that a bathtub is a very unfavourable dynamic environment, any rolling motion of the boat will virtually immediately cause the water to start sloshing and create a feedback on the rolling motion. I expect behaviour on open water to be much more sedate, because any waves made will move away from the boat, not immediately return the energy. She will roll a bit, no doubt, but nothing scary.
Stability is a bit more complicated than just putting weight in the lowest point of the ship.
There's static stability (basically the height of the CoG in relation to the height of Centre of Buoyancy) and there's dynamic stability (a bit harder to explain, but in the bottom line it is the integral of the righting couple graph).
Theoretically, static stability is a torque (force times leverage), the dynamic stability is a ""labour", an amount of energy (torque over an angle of movement).
Inertia around the rolling axis is what absorbs this labour, and the lower that inertia, the faster the roll rate (shorter cycle time of the oscillation).
Most people don't know this, but both in models as well as in real ships, the CoG is actually ABOVE the centre of Buoyancy, and stability is achieved by the shift of Buoyancy due to list angle. The amount of shift per degree of list is determined by the shape of the hull and the draft, and the relation is not linear. When a graph is made of this buoyancy shift against roll angle, the eclosed surface below the graph (the integral of the graph) this represents the righting energy.
And as it is (I tested that) it still takes a considerable amount of force to push one of the boards in the water. Way above what any gust of wind could achieve.
There is a reason that I want to increase inertia and reduce static stability, and that is that it prolonges the roll time.
Look at it like this: the flywheel is a big mass, with a lot of inertia of its own (it basically spins freely around an axis that is near coinciding with the hulls' axis of roll) and due to that inertia it will want to spin a constant RPM.
The sensor that pics up that speed, is fitted to the hull, so any rolling motion will affect the RPM signal (the rolling motion of the boat is added or subtracted to the actual rotational speed. This triggers a correction signal.
If the boat is rolling really violently (low centre of gravity) this can lead to oscillation and increase the amplitude of the roll because any control system has a time lag.
If you think this is theoretical blah blah, I have seen it happen 7 years ago with the first execution of this project. It is real and it does happen.
That hull was too small to add any ballast, that's why that project was stopped.
In fact, it happened in this hull as well, without ballast, and it was so violent I could not video it (needed the one free hand I had to hold the boat instead of the camera :D).
Letting the boat loose, the interaction between rolling motion and governor action could clearly be seen, holding the boat reduced governor corrections visibly.
Increasing the draft reduces dynamic stability, but adding weight at the lowest point will increase static stability, while not doing much for inertia (weight added at the lowest point, that weight will have a distance to the rolling axis of only 4 cm). So I added weight on the waterline, in the sides, where that weight won't add to static stability, but have more effect on inertia because now the weight is about 9 cm distance to the rolling axis.
It works, because the boat does not tip over and though there still is SOME interference between governor and rolling motion, it is not much, and it is a bit load dependent: it mainly happens at neutral pitch and is virtually gone when the engine is loaded, despite the constant corrections of the governor still being there.
That it works, is evidnced by the fact that I could actually MAKER the video (I had one hand availlable to hold the camera :D).
A big issue is that the governor I use (Futaba GV1) has very poor PID adjustability, and part of it is done in a "hidden menu" that was never intended for the end-user, and there is no proper description of these parameters availlable. Futaba used very non-typical names and I have not been able to either find any additional info online on this, nor was I able to analyze the changes in response in order to figure out what these parameters actually do.
I managed to get some improvement 7 years ago, but that was a matter of trial and error, like a blind man in a maze...
Unless I can find a proper PID controller, that I can tune the way I am used to tune controllers, the only thing I can do is to further dampen the movement hydrodynamically, and right now the only remaining option are bilge keels. I used those in the first attempt, 7 years ago as well and they had noticable positive effect.
There are still a few issues with carburation, making the engine respond less optimal to governor imput, and that is a totally separate issue, but it is illustrative that when I put the boat on the stand with running engine, things quiet down considerably, and in fact, first tests on the stand were actually done without any form of active RPM control, which is remarkable because normally, unloaded engines tend to "runaway", and 7 years ago this was impossible, so I think the adaptation on the valve timing I did a week ago has a positive effect on the engines behaviour.
So there still is also some to be gained by "undiluted" engineering, but that is a separate issue.
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Looks amazing, it’s lovely to see a new build scale boat with a proper engine in it
Don’t think you’ll ever stop the torque roll you’re getting from that gigantic flywheel - I’ve seen smaller on full size boats ;)
Thanks! It really is a fun project. I did not build the boat for beauty, but at least it had to look decent.
Fully agree, I do not expect to stop the torque roll completely, but the challenge is to eliminate it as much as possible.
There are several ways to do this, and I think I have to walk all of them... :D
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Well... I have to admit defeat...
The engine DOES need cooling.
I really don't get it, actually, because I have not seen this engine running significantly over 100 deg C (maybe 110 or so) while I have an identical engine in a plane (also running gasoline BTW) that happily chugs away at 135 deg C all day long, holds full throttle indefinitely and delivers approx 10 times the horsepower this thing does.
So I fitted a 42 mm computer fan (with a pro forma temperature control range from minimum speed at 70 degrees C to full speed at 100 degrees, but I have the strange feeling it will run full speed all the time, so... %) ).
(https://www.modelbouwforum.nl/attachments/20231108_215647-1-jpg.560421/)
(https://www.modelbouwforum.nl/attachments/20231108_215704-1-jpg.560422/)
The fan is currently powered by a separate 3S LiPo, current draw approx 90 mA so a very tiny battery allready suffices, but I intend to change that to a single 3S LiPo supplying fan directly and ignition and RX/servos via a voltage regulator.
Also a tiny modification done to the carburettor (a restrictor in the intake, "calibrated" to do nothing at low loads, but increase intake vacuum at high loads, increasing fuel draw when the engine has to work harder, a necessity for engines running a constant RPM). It looks ugly, nay HIDEOUS, but it works a treat.
It is a simple 1 1/4th" length of 1/8" diameter brass tubing, glued into "something to hold it in front of the (now useless) velocity stack".
(https://www.modelbouwforum.nl/attachments/20231108_220210-1-jpg.560423/)
And WHAMMO... suddenly the needle could be closed a fair bit more, smoothing out the engine, reducing the torque-roll and full power is now "endless" (it had a very strong tendency to cut out at full pitch, no real problem because it would run OK up to about 90% and I could live with that).
https://www.youtube.com/watch?v=j0Z5EHk_r7I (https://www.youtube.com/watch?v=j0Z5EHk_r7I)
Prior to starting the camera there was a 4 minute warm-up run, where I also leaned the needle a bit.
After the vid I continued for about 4 minutes (all four of them full ahead) and then I checked fuel consumption: 7 ml... on a total tank content of 17 ml, meaning there's about 30 safe minutes in that tank.
I'm happy... I think... <*<
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The engine in the plane will not overheat as it has a big cooling fan in front of it. Fully cowl the engine and block off the airflow round it it will rapidly overheat, open up openings in the front of the cowl and behind the engine it will then run at normal temperature. Cars and helicopters which don't have a propeller have much larger cooling fins on the head to try and keep them cooler with much less airflow. Your boat installation would need these larger cooling fins or a water jacket to stay at the temperature you want.(It's a little known fact that the propeller at the front of a plane is actually a cooling fan for the pilot, if it stops you will see him rapidly start to sweat. {:-{ {:-{ )
Jim
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Expectations met and exceeded, here's the maiden:
https://www.youtube.com/watch?v=Hfr7a31O0Tk
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The engine in the plane will not overheat as it has a big cooling fan in front of it.
I know how those things work, ;)
the thing is that the aircraft version of this engine runs all day long at 135 degrees and full chat (200 Watt approx), this thing did not accept 110 deg C (while producing at best 20 Watt).
That's what I don't get. Cooling or not, temperature is temperature... And the cooling effect of this tiny little fan is minimal, I mean, the air movement is barely noticable, but the effect on the engine is disproportionally big. From barely adjustable, irregular running and requiring an overly rich mixture to nice smokefree, lean and as regular as a swiss clock. That's what I don't get...
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Dang... I just realized: This was a 13 day build, from bare hull to maiden voyage...
Still a lot of detailing to do, but neverhtheless... Crazy two weeks...
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Today I tried to determine fuel consumption a bit more accurate.
On the pond, so far it looked like about 24 ml/hr
Apparently (I did not expect that) propellers turn easier in a bathtub, because 15 ml filled to the tank, lasted for more than one hour at basically continuous full pitch...
Hmmm...
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Just for fun, AND a little bit to check if there ain't anything funky going on with the engine internals, a slow down of the engine sound (1/8th of original speed).
https://www.youtube.com/watch?v=5N2cbjF6nbQ
Suddenly it REALLY sounds like the real thing...
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Today I tried to determine fuel consumption a bit more accurate.
On the pond, so far it looked like about 24 ml/hr
Apparently (I did not expect that) propellers turn easier in a bathtub, because 15 ml filled to the tank, lasted for more than one hour at basically continuous full pitch...
Hmmm...
This fuel consumption seems to be consistent... that first test took 65 minutes to go through 15 ml of fuel, the 2nd test, 2 clicks richer, burned 16 ml in 61 minutes
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An impression of yesterday afternoon.
40 minutes on 10 ml of fuel, engine ran non-stop and never skipped a beat, despite having a bit of trouble to get warmed up (it was pretty chilly). Once it runs, it runs until either the fuel runs out or the prop tangles in waterplants.
The boat manouvres extremely well with the variable pitch propeller. Good fun!
https://www.youtube.com/watch?v=N1i9OioMMFw
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1967 Butus,The engine sound and speed seem matching very well for me and generating nostalgic atmosphere by the scene :-)) O0 %% .
And the environment around the water way is also impressive as if I were in Huis Ten Bosch, so called theme park in Japan. %%
Well, this forum has become very international, hasn't it ...?? {-) O0 :-))
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1967 Butus,The engine sound and speed seem matching very well for me and generating nostalgic atmosphere by the scene :-)) O0 %% .
And the environment around the water way is also impressive as if I were in Huis Ten Bosch, so called theme park in Japan. %%
Well, this forum has become very international, hasn't it ...?? {-) O0 :-))
Thanks, Back...
I had to google "Huis Ten Bosch" in that context of themepark in Japan... I was amazed, I was not aware of that.
But it goes to show that the Japanese have apparently built a VERY realistic themepark! For which I salute you guys! :-))
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Really nice result there. I have a river cruiser that runs nice and slowly with an electric motor but a model running slowly certainly benefits from an engine noise and if that's from a real IC motor than so much the better.
Chris
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Thanks, Chris!
Managed to get the governor response a bit mellower, reducing torque roll, and as I type, busy painting on the waterline.
Every day a little bit detailing.
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Thanks, Chris!
Managed to get the governor response a bit mellower, reducing torque roll
Here's a vid of that mellower governor response:
https://www.youtube.com/watch?v=EeExUNp7Gus
I also managed to determine that the controlled cooling fan actually controls... The fan speeds up if load on the engine is increased, balances at a constant given load, and slows down again when the engine unloads.
I have no idea what the actual running temperature (metal temperature, I mean) of the engine is, but the control range of the fan is from 70 deg C (minimum speed) to about 100 deg C. The probe is stuck between the fins of the head, approximately between intake and exhaust port, no idea what the misreading of the probe is... OTOH, I do not think the exact temperature is critically important for an aircooled engine, more important is that cooling supply follows cooling demand.
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reducing torque roll...
Anyone can judge for themselves...
Before:
https://www.youtube.com/watch?v=t8S6NmNbQz4
After:
https://www.youtube.com/watch?v=c9dG6fheH48
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Wow!! Certainly, greatly, realistically, stably, neatly, nicely, decently, dexterously, marvelously much improved,1967Brutus,!! :-))
I don't now any other adverbs except the above to express my impression on the above awesome progress. :-)) :-)) :-)) {-)
Well done with your tenacious efforts for the improvement. :-)) :-)) :-)) But take much care not to drop her.!! :-))
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But take much care not to drop her.!! :-))
Sometimes I think people are claircoyant...
By accident I actually DID drop her a few days back, after painting on the waterline... Broke the portside bulkhead of the cabin in the process...
I nearly blew a gasket and an artery or two... >:-o >:-o >:-o [size=78%] Ooofh![/size]
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Last round before going back to sea. First real-world test of the new RPM control adjustments.
Increased maximum rudder deflection a bit as well.
https://www.youtube.com/watch?v=20EiBJfWSSo
I'm happy... See y'all in the next year!
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I remember your experiments with the ASP 30 FS over on RCG years ago. Nice to see it going in this lovely model boat! :-))
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I remember your experiments with the ASP 30 FS over on RCG years ago. Nice to see it going in this lovely model boat! :-))
Thanks Tom,
It has been an adventure for sure.
7 years ago or so I did a lot of work getting it to run in the first place, but back then the hull I had turned out to offer no more room for development.
The whole thing kept simmering in the back of my mind, and because of changes in my life I decided to take on boats for a while, and with that also resurrected the low speed engine project.
I think it turned out nice, and truth be told, technically I think I'm pretty much as far as I will get this project, but cosmetically, there still is a fair bit to do. And I have to say, every time I add a bit to that, it is as if I'm taking a new boat out. Pretty satisfying to be honest. And.... No stress...
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That's what's keeping your interest going. Often once a model is finished the interest can lessen.
For many of us the research and building is the best part.
Chris
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Absolutely!
Although "operating a system" also has its charms, which is why I don't do electric main power, but something like this gasoline engine, or he steamboat I built a few months back. It keeps the mind alert when you have something to listen to and supervise. Piloting the boat around is not that challenging...
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The other day, I bought an exhaust gas tester (CO meter) for working on my bikes, and since the little fourstroke is VERY tricky to tune (the engine is governed, therefore it does not change RPM or exhaust note when changing the mixture) I was wondering if CO measurements would be of assistance.
Well, whaddayaknow... it does! I fired up the engine,as well as the meter, and found that it was running horribly rich at about 10% CO...
Previously, leaning out would not give any visible, audible or otherwise noticable change except that at some point the engine would start stalling.
But with the meter I could "relatively easy" dial it down to about 3,5% CO which turned out to give best RPM and governor stability without stalling the engine.
Hooking up the exhaust to the meter was a bit of an improvised mess (no vid or pics unfortunately, I needed both hands), but I managed to video the governor response with a properly adjusted carb. I could, thanks to this, remove the servo-slowdown on the pitch servo to zero.
The vid is narrated in dutch (sorry about that) but every time you hear me saying something, I am shifting the pitch from either neutral to full or from full astern to full.
https://www.youtube.com/watch?v=O4Mg61lg12w
The exhaust is also noticably less smelly and smoky...
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Slowly, VERY slowly, also some cosmetic work is being done...
https://www.modelbouwforum.nl/attachments/20240223_102911-1-jpg.572737/
It took a while, but the windows have finally been fitted (still need a bit of cleaning up of the sills) and the cabin door (not yet in place in the pic) has its latching magnet keeping it closed.
It ain't much, but it's progress at least... :D
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Looking good and getting there, tres bon :-))
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Thanks!
It seems that I am one of those "hit&run" builders that builds a boat (the functional part) then waits forever before finishing it, and WHEN finishing, it is short bursts of single details at a time...
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As a fighter for the interests of seafaring people, I am a staunch opponent of unmanned vessels... So...
(https://www.modelbouwforum.nl/attachments/20240224_120219-1-jpg.572958/)
and in my 32 years at sea, I have learned the hard way, that sailing without coffee, is a resolute impossibility... (Heck, LIFE without coffee cannot be sustained IMHO)
(https://www.modelbouwforum.nl/attachments/20240224_121306-1-jpg.572959/)
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And single-handed sailing is utterly boring, so:
(https://www.modelbouwforum.nl/attachments/20240225_163655-1-jpg.573364/)
(https://www.modelbouwforum.nl/attachments/20240225_164907-1-jpg.573367/)
The coffee mugs were made from loose items (caps of plastic vials, the handle a piece of black insulated 0,75mm2 electric wire).
Now I'm looking for something that can mimic a thermos... Because a coffeemaker is too hard to do (and not very realistic... :D)
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Looking Good!
( You just need to put [img ] [ /img] around your photo Links - No Spaces ) :-))
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Looking Good!
( You just need to put [img ]http://[ /img][/img][/color] around your photo Links - No Spaces ) :-))
Thanks! I continuously amaze myself because I am totally not a "details" freak normally... A sudden outburst of coffee mugs and crew... Thinking about how to simulate a thermos... Heck, it's like I'm not myself today.Thanks for the tip on the pics, I'll keep that in mind! (and thanks for inserting a few for me :-)) )
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Just as an experiment with martins's tip for the pics:
Glueing in the windows, I smudged a bit of glue on them as can be seen here:
(https://www.modelbouwforum.nl/attachments/20240224_120219-1-jpg.572958/)
cleaning them with car wax improved the front windows considerably:
(https://www.modelbouwforum.nl/attachments/20240225_175640-1-jpg.573387/)
Whaddayaknow... it WORKS...
Thanks Martin!
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OK... now I am officially overdoing it...
As I said, I am normally NOT a guy that loses himself in tiny details...
So I guess I can officially say I got a bit carried away:
(https://www.modelbouwforum.nl/attachments/20240226_183443-1-jpg.573665/)
You can't sail without coffee, but engineers need tabacco as well... Hand-rolled... :p
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https://www.youtube.com/watch?v=UhCiLWfoBS4
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:D last week I showed the video above to one of my colleague engineers at work, and his first and immediate remark was "that sound is fake, you edited a recording of a real engine over it"...
I had to show him a more close-up vid of the engine to convince him... :D :D :D
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That's because so many are used to hearing the electrical buzz saws fitted to many of our toy boats and not 'Propper' engines. Wonder if a Mastiff would blow his auditory receptacles?
Regards Ian.
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The guy was, like me, a marine engineer. Don't know if he had any affinity to modelling though...
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Just because it was a nice and relaxing hour at the waterfront...
https://www.youtube.com/watch?v=-NSF377WN7Q
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The little engine that could, racked up 22 hours since this project was maidened, bringing total waterborne runhours to 30...
https://www.youtube.com/watch?v=wy_8oFOjbGU
Additional to that it spent some (not exactly accounted for) 45 hours of testing, about 7 years ago.
https://www.youtube.com/watch?v=fW8TD3qvjws
Amazing resilience against the abuse I subjected it to over the years :D
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In the months since last post, another 8 runhours have ben gathered, this evenings session consisted of 1,5 hours non-stop with two refuellings (running engine), for a whopping fuel consumption of 19 ml in total.
This thing does not cease to amaze me.
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But with a little it luck it will be barely visible once the salon is done:
(https://www.modelbouwforum.nl/attachments/20231031_090357-1-jpg.559093/)
This servo (Hitec HS81, approx 1 kg/cm) apparently was not strong enough, it caved in a few weeks ago. Dead as a doornail.
Replaced it for a slightly larger, but 3 times stronger servo, Robbe RovoR FS 0270 MG BB, that is claimed to pull 3 kg, ballraced and metal gears...
(https://www.modelbouwforum.nl/attachments/20250517_151225-1-jpg.618349/)
That should do it...
EDIT: apparently, that old Hitec allready spent quite a while dying... A short test in the bathtub showed a HUGE improvement in precision and fine-control.
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This servo (Hitec HS81, approx 1 kg/cm) apparently was not strong enough, it caved in a few weeks ago. Dead as a doornail.
Replaced it for a slightly larger, but 3 times stronger servo, Robbe RovoR FS 0270 MG BB, that is claimed to pull 3 kg, ballraced and metal gears...
(https://www.modelbouwforum.nl/attachments/20250517_151225-1-jpg.618349/)
That should do it...
EDIT: apparently, that old Hitec allready spent quite a while dying... A short test in the bathtub showed a HUGE improvement in precision and fine-control.
Working out nice: https://www.facebook.com/100003496789015/videos/pcb.9539298439529954/9942206222538288