Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: MONAHAN STEAM MODELS on November 20, 2009, 12:16:46 am
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This wonderful engine was built by the extremely talented late Peter Baylis of MHB. I wanted to share this engine with the forum members here because I thought that some of you would like to see this rare engine. This engine was a proto type and is the only four cylinder that was ever built by MHB. The engine has never been steamed but has been run very briefly on air. I can say that it runs very smoothly and the beautiful craftsmanship stands as testimony to Peter's talents as a model engineer.
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Absolutely beautiful, many thanks for sharing the pictures with us Nick. Who is going to be the brave man to put that into a boat?
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I can't even bring myself to run it on steam for fear of it losing it's pristine condition let alone install it in a boat. :embarrassed: Brian Marten told me that this was the last engine they ever built. I feel like an over protective guardian of it. I feel the only boat worthy of this engine would have to be a MHB boat. It was originally designed for their torpedo launch which was going to have twin port and starboard Topaz style boilers. :-))
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Nick, a lovely looking piece of craftmanship. For those of us who are not fully conversant with the more complicated engines such as this could you please do a run down on some of the features? For instance does the valve control speed and direction and if so how? I thought it needed two separate controls on a slide valve engine. What is the set of gears and lever at the front of the crank for and what are the four tubes down the side of the engine, do they oil the bearings? Thanks in anticipation, Ian.
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Until I saw your photos, I had not realised just how much Cheddar 'borrowed' from MHB for the Proteus and Gemini engines. I have a Gemini here and the family ancestry is clear.
Shame not to use the engine, but on the other hand, there is an awful lot of history right there!
Thanks for sharing.
Neil
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I'm sure Nick will clarify but it looks to me like the lever at the flywheel is a reversing lever, using gears to reverse the engine in a very neat arrangement. The valve on the steam inlet will therefore be for engine revs control only.
From what I can see the oil cups on the tops of the pillars supply the small tubes going to the piston rods. What a lovely way of doing it.
Beautiful engine but I think it would be a shame to sit and simply look at it forever. It would look superb in a MHB hull though!
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Beautiful, what a lovely engine.
Would be a shame not to use it Nick- you could always build a copy though i'm sure..... :-))
Greg
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Hear is a single version for my mini Vap plus cheddar boiler , they did a one two and three cylinder plus the one off four.no reverse on mine so using a gear box.there was a three for sale recently but I missed the end or I would of had a good go at buying it.
peter
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I'm sure Nick will clarify but it looks to me like the lever at the flywheel is a reversing lever, using gears to reverse the engine in a very neat arrangement. The valve on the steam inlet will therefore be for engine revs control only.
Yes, that is spot on Bunkerbarge. At one time Cheddar did a mixer for two servo's, that would shut off the steam and move the gear engagement then reopen the steam all on one stick. The alternative is just to use the throttle stick to open the steam feed and have another channel (and servo) change the gears.
HS, like that single. I've never seen one of those before.
Neil
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Ian.....the tumbler gear sets are 'Maudsley' reversing gears ...I tried to post a jpg earlier but the :police: stopped me ....Derek
PS when you consider the design.......there is no syncromesh or clutch....so.....must ZERO the engine RPM .....then jiggle the reversing lever whilst establishing the first revolutions of the opposite direction O0
Todays model representation displays a single lever @ 90 degrees for a servo..........however I believe the actual mechanism would have been a dual fulcrum on either 'side' of the engine with substantial mechanical advantage ....... {-) :-))
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Great Engine Nick.........IT IS MADE TO BE USED...SO IN A BOAT WITH IT,,,,,,,,,,,
Regards Bernhard
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I am inclined to agree with Berhard, when the creator of this engine built it, he did so with the intention that someone would get the joy of running it. If keeping it in a glass case gives you joy and pleasure then that is absolutely fine, but if kept that way it would still tarnish over the years and one day, someone would inherit it as a tarnished engine , strip it down and polish it up again. That would probably do it more damage than having it correctly set up as a running machine. It doesn't fulfill it's intended role if it sits on the shelf, neither does it do justice to the designers efforts. We only come this way once so enjoy to the full the beautiful gifts the designers and builders of such exotic machines have given us.
Personally, I would run it and derive great satisfaction and pleasure from the fullness of ownership.
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Hi Ian, Derek is correct, the gears on the front of the engine's crankshaft is a "Maudsley" reversing mechanism which requires one servo. The engines speed is controlled by the throttle valve located on the side of the valve chest by a second servo. The vertical column supports are partially hollow with oil cups at the tops of them. There are small brass tubes pressed into the sides of the support columns which the oil from the oiling cups flows through to provide lubrication to the piston rods. The crankshaft is supported by a number of stainless steel sealed ball bearings.
Hi Neil, The Gemini was born out of the PB2 design from MHB. John from Cheddar was good friends with Brian and Peter from MHB and was given permission to borrow the design to produce the Gemini engine. The designs for the PB2 were never sold to Cheddar, they were just on loan as long as Cheddar produced the Gemini engines and supplied them to MHB for use in their kits. Both the Gemini and the PB2's are great engines!
Hi Peter, That is a neat compact steam plant. I really like the single cylinder engine. Thanks for sharing.
Hi Sheerline, Well said! I completely agree. In fact you have all have made very good points here. The engine probably should be used and enjoyed since that was the reason it was built. I still feel that it should be placed into a MHB kit though. Would you agree? I think it would be neat to put the engine into the MHB torpedo launch with the twin boilers as it was originally intended for.
Best Regards,
Nick
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Nick,
that would be one speedy model.
I remember MHB attending a Cheddar open day with a prototype Der Seekadett, that had the triple engine fitted (just before Cheddar started to produce their engines). Something went wrong with the radio and the model shot across the full width of Cheddar's demo lake at full speed, hit the slope at the edge of the lake and shot up onto the bank.
Needless to say, John Woodroffe thought it was fantastic (he did love fast steam boats).
There was no harm done and the model was back on the lake a short while later.
Neil
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MONAHAN STEAM MODELS
I saw the torpedo boat test at cheddar, the where the normal how can we make it lighter cannot remember the engine for test they had a Proteus boiler I think.can you not get the test hull I think they had a few made I was going to get one but gave up the waiting, I think he had done the front deck gun at the time, and most of the plans
Underpressure
I was there the weekend the Proteus was realised and Ian had Put one in a slim hull speeding about the lake and pulling the dingy.
only picture I could find at short notice
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HS,
I was also there that day, small world. The model was called Arrow.
I can't remember if it was the same weekend, but do you recall they fitted a Proteus and boiler into the dingy. Ian and I then sailed around the lake in the dingy, driven by the Proteus with Ian operating the 'plant' and me using an oar to steer.
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You know you guys really should join the SBA and get 'proper' steamboats!!!!!!!!!!! O0
Greg
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HS,
I was also there that day, small world. The model was called Arrow.
I can't remember if it was the same weekend, but do you recall they fitted a Proteus and boiler into the dingy. Ian and I then sailed around the lake in the dingy, driven by the Proteus with Ian operating the 'plant' and me using an oar to steer.
Yep that was it a very warm weekend. I joined the club that day. and Test it was the the steam plant in the row boat that had no rudder , where you thee when john slipped putting the ,markers out. no one dear laugh, did you go to the meals of a night.
gondolier88 l how many will take a wheelchair without me being manhandled ? Oh that many
peter
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Fair eonough HS93 ;D
Greg
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Here's a photo of the MHB Torpedo launch.
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is that yours?
peter
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I wish it was! It was built by a friend on the east coast of the States. I believe this was the first or second hull ever made.
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What is going on with Cheddar's old facility? They had a beautiful shop and lake. Is anyone using the building?
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Beautiful hull!!! Who has the rights to it now?
Greg
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What is going on with Cheddar's old facility? They had a beautiful shop and lake. Is anyone using the building?
The building was taken on by a company that work on highly classified projects. The land all belonged to John's brother Ken and his widow sold the factory but not the land beyond, so although the company would prefer the steam club was not there, they cannot evict them as Ken's widow wants them there.
Peter knows more about the recent history of the club than I do, but the it's still there and I have arranged to visit on the next club day.
Peter,
I remember John slipping in, and the stunned silence. I did not go to the evening meal, as I only live 20 minutes drive from the lake. If you had a boiler test done by the club that weekend, then I carried it out. I was the only boiler tester at the club for about 18 months, although we did have a guy in the Lake District and a couple more over in Essex.
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It still belongs to MHB. They were developing it for years with the plans to make a full kit out of it but decided only to make a semi kit after Peter's passing. I know Brian is really busy lately but if you ask him nicely he'll probably build you one! %)
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The building was taken on by a company that work on highly classified projects. The land all belonged to John's brother Ken and his widow sold the factory but not the land beyond, so although the company would prefer the steam club was not there, they cannot evict them as Ken's widow wants them there.
Well I am certainly glad to hear that the steam club can still use the lake. :-))
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The building was taken on by a company that work on highly classified projects. The land all belonged to John's brother Ken and his widow sold the factory but not the land beyond, so although the company would prefer the steam club was not there, they cannot evict them as Ken's widow wants them there.
Peter knows more about the recent history of the club than I do, but the it's still there and I have arranged to visit on the next club day.
Peter,
I remember John slipping in, and the stunned silence. I did not go to the evening meal, as I only live 20 minutes drive from the lake. If you had a boiler test done by the club that weekend, then I carried it out. I was the only boiler tester at the club for about 18 months, although we did have a guy in the Lake District and a couple more over in Essex.
He borrowed a spare set of clothes I kept in the car, it was so funny, I have never seen so many smiling faces all week end.I took a lot of pictures that week end IL post them separately. there where a lot of French there that weekend, so John made shore it was BEEF to wind them up at the Meal.
peter
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You know, looking at that torpedo hull again- it is on VERY similar lines to 'Bat' in whats left of the WSBM- i'd love to have the hull and put Bat's machinery in- would go like bat out of hell (no pun intended!!!)
I know Hemmens did a model years ago, but not at that scale- you could have a proper Liquid Fuel boiler (gas fired of course!) and a miniature compound, maybe the ST Compound Launch- at that size and with the full beam engine casing you could make up a simpling valve arrangement.
Can just see it now...in my dreams!
Greg
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Nick, that Mh&B is a really interesting engine. What's the reason for using 4 cylinders, as opposed to 2 larger ones for instance?
Why and when did MH&B stop making steam engines? I saw they offer now Anton engines for their boats.
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4 smaller cylinders gives you higher rpm- which in a model is a useful thing.
Greg
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also they are all built of standard parts so they only need one cylinder housing and they can use it and the valve gear on any of there engines they could build a 16 cylinder if they wanted.
they reason for them starting to use Anton was that they had moved to Cheddar engines and when they stopped trading they went to Anton again with there Boiler's and why did they stop well they had retired from there day job some time before MH&B started and they wanted to concentrate on new Boat kits from what I can gather.
peter
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The full sized Torpedo launch that the MHB kit was modeled after originally had a four cylinder compound engine with twin boilers. So they developed this engine for that kit.
Also everything Greg and Peter have said is correct.
When MHB was still making their engines, they were using manual, non-CNC machining equipment. There is nothing wrong with doing that at all but, this makes an already time consuming laborious job even more so. With that said, this coupled with the fact that there is really no profit in making complex steam engines after you add up all the hours and costs and subtract that from what most people are willing to pay for an engine, it starts to become understandable why it made more sense for them to purchase engines from outside manufacturers.
The same can be said for boilers. However, MHB still makes all their boilers in house. This is due to the fact that their kits require a very specialize boiler which is not available from any other manufacturer. The boilers for the MHB kits have to be a very specific weight and size. The result from this, has been MHB's development of some of the best preforming, lightest weight, quickest steaming, boilers that I have seen yet produced by any marine boiler maker. I can tell you personally as a boiler maker that the amount of additional labor that has to go into the construction of each MHB boiler far exceeds that of a similar sized boilers from other manufacturers. Regardless of the extra labor involved, MHB still offers their boilers at a reasonable cost. :-))
Nick
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Thanks Nick! Which are the special features of the MH&B boilers?
I guess they must use something other than copper to save weight? I'd like to see some good photos of such a boiler, if you ave any.
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Hi Guys
Just looking at that beautiful engine and would like to have a go at building one similar one day hence a couple of queries.
1 I notice there seems to be no slide support for the connecting rods I don't want to sound negative as there may be a reason , also wondering how the valve rods keep contact with the cams
Cheers
John
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Hi South Steyne,
I think you may be a little confused?
The connecting rods on an engine of this size don't produce anywhere near the power to warrant a crosshead slide- however the bottom cylinder cover has integral trunk guides which is enough for this engine- especially as it's a four cylinder so all the forces will act in a square around the crakshaft.
Secondly- the valves arent working off cams, they are just standard eccentrics. Many single acting engines in full size relied on cams though.
Greg
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Thanks Nick! Which are the special features of the MH&B boilers?
I guess they must use something other than copper to save weight? I'd like to see some good photos of such a boiler, if you ave any.
Hi Kno3,
The MHB boiler's main boiler wrapper or shell is made from a specific grade of nickel silver sheet which is rolled into a cylindrical barrel. The lap seam is riveted and then welded forming a very strong joint. Depending on the grade and sheet thickness or gauge of the Nickel silver, when compared to copper it is has about 1/10 the thermal conductivity and can be 2-3 times stronger at half the thickness or gauge. This allows for significant weight savings over copper and increases performance since the main boiler shell is not acting as a heat sink and sucking up all the heat generated from the burner then radiating it away regardless of insulation or lagging. The end plates and flues are still made from copper. Another feature of the MHB horizontal boilers is the return flue which allows the heat generated by the burner to remain in the boiler longer before exiting up through the stack. MHB also incorporates a super heater located in the upper return flue which also adds efficiency.
To give you a rough idea of the steam output generated by a MHB Seekadett boiler, Brian and I collaborated on a project for a client. I made a few modifications to the design of this boiler to suit the needs of this particular project we were working on, then sent the designs to Brian and he produced the boiler. This custom MHB Seekadett boiler provides more than enough steam to power the mirrored pair of Heron engines that are connected to it. :-)) It also comes up to steam quickly. When I have a moment of free time, I will take some pictures of this boiler and post hem here.
Nick
Nick
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Have you ever thought about using a 'gunboat' type boiler as a lightweight option nick?
I'm sure you know the type, but to resume- shell boiler, horizontal, firebox is a cylinder or stayed oblong in the same location as in scotch boilers, however it doesn't run all the way through, probably about 1.5 times it's width, it then has a tubeplate at the end where the tubes run through the barrel to the smokebox tubeplate, or it can be a dryback return with the tubes running back over the primary tubes and firebox to exit above the firedoor and up the funnel (or if your that side of the pond, stack :-)) )
It could be made lightweight due to it having a large heating surface and doesn't have to have a large footprint. Also space for a superheater is easily available.
Greg
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Hi Greg, :-)
It's funny you should mention that design. I actually built one a few years back. They're are good boilers. Currently, I am in the midst of designing and building a LIFU launch for a client. The boiler for this launch will be a scale version of a real horizontal LIFU water tube boiler.
Nick
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Greg, do you mean a wet-back Scotch boiler?
Nick, thanks for the answer, I'd love to see the pictures too. Can nickel silver be silver soldered to copper the usual way? Would you recommend it for a homemade boiler?
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Hi Kno,
No, a wetback scotch has a full length firebox with return tubes.
Nick,
Fantastic- LIFU boilers are great- are you doing the two drum U-tubed type?
Theres quite a few in the SBA, theres a couple of the three drum types too- see my windermere steam rally thread in the other steam section, the boat I was on, 'Souvenir d' Antan' has it's original LIFU three drum, 30hp(?), with it's builders own design engine, a large compound.
Greg
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Nickel silver can be joined to copper the usual way with silver solder. There are many grades of nickel silvers available each having a specific purpose and each being a slightly different blend or composition of various other materials or metals. Some countries have different material # designations for it that differ from one country to another. So the only sure way to compare nickel silvers is to look at their composition. But there is more to it than that. With out knowing your welding, fabrication, or boiler designing skills personally, for legal reasons I am sorry but I can not recommend nickel silver for a homemade boiler. I'm sure you can understand my position. You can still do your own research. In fact when ever designing anything, it's best to do as much research as possible in order to fully understand every aspect of a design. Never take anything that has to do with safety at face value.
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Hi Greg,
For this model I was planning on doing the 3 drum type. We actually have two real full sized water tube boilers at our other shop which incorporate the U-tube style of drum. One of them is in our 46 foot Stern wheeler. The other was taken out of a steam launch and placed on a custom built cart on wheels. We use it as an auxiliary boiler for powering all the smaller engines we have. It's impressive how efficient full sized water tube boilers are, which is why I've always wanted to produce some model versions of them. I may start to offer the LIFU launch a kit with the LIFU style water tube boiler available separately.
Nick
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Nick, I understand your position, thanks for the answer. I'll do some more research before deciding what materials to use.
My problem is that short (under 15 cm) and light boilers are not generally offered ready-made, and I need them for small boats, in the 35-50 cm range. If you know of any...
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Greg,
Here's a couple of photos of one of our water tube boilers. This is "Little Baby Steamy Pants".
Kno3,
I understand your need for a small light weight boiler. I have them designed but it will be a while longer until we can make them available.
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Hi Nick,
Yes, I've been contemplating making a model sized watertube boiler myself- though i'm tending more towards a Yarrow type. However, when all said and done, there isn't much between later watertube designs, they all use roughly the same ratio of length to thickness and most had roughly trhe same water volume.
Again, if you need any help with details just ask- theres plenty of old boilers over this side!
Kno,
If you want a truly lightweight steamplant watertube really is the only way to go with a high RPM high pressure twin with engine driven feed pump and under-hull waterpickup.
Although flash steam also has it's merits, but thats a whole diffferent kettle (no pun intended!) of fish altogether!
Is it this LIFU launch that used the Victoria as the testbed for?
I thought you were building a Kingdon to go in it, or had you already built that- memory is getting worse!!
Greg
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{-) 'Little Baby Steamer Pants' is fantastic- SO american!! If that was UK it would have cast wheels and polished brass everywhere and would be someones pride and joy to be shown off, but you guys have a few beers, forget you've still got your hammer and a spanner in your back pocket and wake up with that in your garage- good job your engines aren't made like that eh!!! :-)) :-)) :-)) ;D ;D
Greg
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The other water tube boiler we have is in Wilhelmina our 46 foot paddle boat. Here's some photo's from an event our separate nonprofit steam organization did last year. Wilhelmina was loaded up on a truck a shipped over land from the California to New York to participate in an art show. After Wilhelmina's arrival in New York overland by truck, she supported an enormous sculptural array installed by an artist named Swoon, the larger project's creative leader. She steamed up and down the Hudson river.
Nick
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Interested in your NFP steam org., what are the objectives of it? Well done on undertaking such a big ask, you must have got more than one young person's face to light up on seeing that.
And coal fired too...?
Greg
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Our non profit org is: http://www.kineticsteamworks.org/index.html
Here a few more pics. This is our other traction engine Hortense and our steam powered sewing machine. Don't ask! :embarrassed:
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We have the boiler set up in Wilhelmina to burn either coal, wood, diesel, propane, or bio-diesel (aka Vegetable oil) %)
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The Kinetic Steamworks is a great idea, looks like you have a lot of fun with it.
Greg
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Is it this LIFU launch that used the Victoria as the testbed for?
I thought you were building a Kingdon to go in it, or had you already built that- memory is getting worse!!
Greg
Greg, Thanks for the offer on information for boilers. I will have take you up on that offer. :-))
The Victoria launch I built a while back was somewhat of a test bed for the LIFU launch project since the hull of the Victoria was dimensionally close to a LIFU launch but not close enough. After a few years of digging around for information on LIFU launches, I've finally managed to come up with enough info to produce an extremely accurate CAD model of a LIFU launch's hull. We have produced a mold off of this CAD model. You are correct that I was planning on using a kingdon style boiler. We actually have two designs for the LIFU launches. The first design looks similar to the past Victoria test bed project but with the kingdon style boiler and the second design is built like a original LIFU launch with the LIFU horizontal water tube boiler.
Nick
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The Kinetic Steamworks is a great idea, looks like you have a lot of fun with it.
Greg
Thanks, Kinetic Steam works is a lot of fun! We have a great collective of people who makes up the core organization, all with various backgrounds ranging from aerospace engineers to school teachers. I myself, is only one small part of this group. We are all volunteers.
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Don't mention it- anything to help get proper contemporary model steam boats into production.
I think the two drum boiler would make a great proposition in model sizes, and easy to tool up for production too- two cylinders, four end caps and numerous symetrical u-bend tubes with a casing to wrap it up- you could even offer it for home-building which would cut costs in production and packaging.
I look forward to seeing what the outcome of your thinkings will be....
Don't suppose we can see the LIFU hull CAD profile.... ;D
Greg
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Greg,
I have been on the fence so to speak about the two drum or three drum versions of water tube boilers. Either design would be good really. I like your idea about the home-building version. My main objective is performance and accuracy to the original design. since water tube boilers can be extremely efficient producers of steam they also need to be kept feed with water due to their minimal water capacities. I've come up with a preliminary design for a device to mechanically sense water levels in boilers but it's still in the early experimental stages. When the water level drops to a certain point this device will open up a valve to allow steam to flow to a scale size duplex pump that is also in the works. If i can get all of this to function 100% reliably, then there will be no need to train mice to serve as engineers aboard our models. ;D Seriously though, it could manage the water level in boilers without the need for electronics. However I'm not sure what the market would be for such a complex system. I'm sure a few would enjoy it, but is that worth going to all the trouble for it?
I don't want to let the CAD model out yet and spoil the surprise. %)
Nick
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A mechanical system for automatically sensing the water level and turning the feed pump on and off is a great idea. I'm wondering if it has been done before in model size?
P.S. Nick I've sent you an e-mail.
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To my knowledge it hasn't been done. I've searched for such a system but haven't been able to come up with anything. Regardless, I would like to have one myself so I'm just going to build one.
I just got your email and sent you a reply.
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Nick,
I read of a design attributed to Mr Yarrow where he had connected a steam pump up to the boiler at the level he wanted the water. When the water level was below this the pump is feed steam and pumps water into the boiler normally, when the water level was up the pump was feed water which slowed the pump down. I have always wanted to try this out and see if it would actually work.
Regards,
Gerald.
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Nick,
Glyn Lancaster-Jones at the traditional boatyard, Port Dinorwic is the guy you need to speak to- he makes most of the two drum types in theSBA, and I think he offers it in kit form too.
His www; www.traditionalboatshop.co.uk (http://www.traditionalboatshop.co.uk).
The three drum is the better performer, thats widely recognised, quicker to steam and more water content, with a better circulation.
However that is NOT to say the two drum is a bad boiler, as you know, it is in itself a very good boiler design, just in model sizes it won't hold much more than about 300ml so would NEED a feed pump as you mention. Have you thought of using commercially available boiler thermistors as sensors- could be easily added to either three or two-drum design and use minimal voltage with dead accurate and reliable temperature controlled electrical output, and they come with standard thread to put into bushes which could be soldered into the end caps no problem.
However, Geralds suggestion is a very good one, with water level above the steam supply to the pump it would be a hydraulic motor and would run really slowly- how reliable could you get? Only problem I can see is that in a model watertube boiler on the pond, any slight wave could create waterhammer in the pipe as it pitches and rolls and bu**er the valvechest up, however,as you are the model piston valve king, that would be the answer to that particular problem...
I think there would be a market for it- especially for enclosed models where fitting hand feed pumps is a right farce and engine driven ones are hidden at the bottom of an unaccessable deck void. A little hint towards something that might be worth developing to use in steam, it may already have i'm not sure myself. The devices I talk of are the 'automatic air relief valves' that domestic boilers use and are screwed into the top of the heat exchangers . They stay open and release the trapped air in the top of the H.Ex., when the air is released and water touches the valve it automatically shuts the outlet- I think it works on differential pressures between the gas and water. I'm not sure if it relies on being under atmospheric pressure to work, or if condensing steam would stop it working, but if you could link the device to the feed pump steam inlet...
Really looking forward to seeing the LIFU hull!!!! Put me down for one- fit it out like 'Churr' one of the prettiest launches on the Thames, I think I sent you a pic.
Greg
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Hi Gerald,
You exactly right about MR Yarrow's design! :-)) Thank you. This was one of my first thoughts for controlling the steam pump too.
In order for it to work properly, I've found that the steam cylinders on the pump need to weep a very small amount of condensate out of small drain cocks or something similar in order for the pump to clear the water out and start somewhat reliably each time. The second discovery was the need for a small orifice installed on the steam line entering the boiler at the desired water level. In model sized applications the reliability of this type of system functioning each time was not good enough in early tests. That's not to say that this design is bad or should be abandoned at all. If anything it deserves further experimenting and developing, but after these experiments with the first method, as an alternative for achieving the same results of controlling the pump I began designing two other types of mechanical valves which have the ability to be either 100% closed or open to allow the steam to flow to the pump. This is all still in the early stages of development.
Nick
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The full sized Torpedo launch that the MHB kit was modeled after originally had a four cylinder compound engine with twin boilers. So they developed this engine for that kit...
And a twin-boilered steam plant too...that produces a very huge steam:
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they look like MHB boilers very nice what are they for ??
Peter
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they look like MHB boilers very nice what are they for ??
Peter
Really??? {-) They are exactly to be MHB boilers. What are they for ? Definetely to feed this 4-cylindered engine onboard this mentioned earlier MHB 63ft TB in scale 1' to 1" ok2
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Here's a photo of the MHB Torpedo launch.
Here is a photo of another MHB model of 63' torpedo boat. This one seems to look much more authentic in terms of colouring and details to what USS MAINE had to carry.
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Hi all does anyone have a picture or drawing detail of maudslays reversing gear as used on the Cheddar gemini engines as I find it very difficult to track down info
Cheers
John
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Hi all does anyone have a picture or drawing detail of maudslays reversing gear as used on the Cheddar gemini engines as I find it very difficult to track down info
Cheers
John
Hi John,
Here are some pics of the Cheddar Gemini engine that I did some repairs for a club mate, I hope that these are of help.
George.
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Hi George thank you so much these pics are a great help as I am thinking of building similar having already sourced the gears for the reverse linkage formerly from an old cordless drill.
I will be teeming this up to the yarrow boiler in the making and all installed in the steam tug Joffre also in the making so you can see I am very busy.
I searched everywhere on the net for info on the Maudslay reverse mechanism but sadly the old steam stuff is gradually disappearing even a lot of pics and illustrations on this forum have gone
will catch up
Cheers
John
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Hi, John,
There was an article in Model Engineer some years back. I did have a copy, but loaned it out and it did not come back. Maybe someone on here could find it. If I remember correct you need to have an even number of gears with the first gear on the main shaft and the last gear on the timing shaft pinned to there shafts and all gears in between free turning. I did mock it up with Mechano gears at one time
Gerald.
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Hi George,
Could you post some photos showing the valve gear in full forward and full reverse?
Gerald.
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Hi George,
Could you post some photos showing the valve gear in full forward and full reverse?
Gerald.
Sorry Gerald,
I no longer have the engine and the owner is now deceased, the pics shown are all that I have.
George.
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Do you remember how much the reversing leaver had to move from forward to reverse? with the eccentric in full forward does it not have to turn 180 deg. to go to full reverse?
Gerald.
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Do you remember how much the reversing leaver had to move from forward to reverse? with the eccentric in full forward does it not have to turn 180 deg. to go to full reverse?
Gerald.
Sorry Gerald, it was some years ago that I did some repairs to my friends engine and as I was never interested in going down the Maudsley road reversing gear I never made any notes on the method used.
George.
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OK thanks George,
For such an interesting subject there is very little to find about Maudsley reversing gear.
I did find a U tube video that does give some information;
https://www.youtube.com/watch?v=w0NkK9wpTDk
Gerald.
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Hi John
I did build an engine with this sort of reversing gear back in the 1980's. I'm afraid the photos aren't too good and you can't actually see how much the eccentric shaft has moved, but I can tell you that it is about 100 degrees. For the engine shown which is 5/8 inch bore and stroke the lever to move the gear needed rather more force than was safe to use with a standard servo so you can see that I used a small steam cylinder to operate the gear. In use it was brilliant and would go from full ahead to full astern in a flash.
It was used in a 50 inch steam picket boat as in the photo.
Malcolm
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Oh! unfortunately the photos of the engine seem to have got lost so I'll try again.
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Hi all,
I am so intrigued by the Maudsley reversing gear. Both the Cheddar Gemini and MHB engines look very nice indeed. Trying to get to grips with the mechanism. Can see that the gearing ratio is simply 1:1 and how the timing would work in one direction. I am I right in assuming that it is the length of "throw" of the gear train that sets the eccentric shaft to the reverse position. Trying to get by mind round it, and to understand what is the difference in degrees of the eccentric shaft between that of forward and reverse? Can also see that the valves need to be on the side that would lead to squat engine.
Malcolm, you say you built one; Can I ask to what design, are they any drawings?
Ian
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Hi Ian
The engine is my design, and the "drawings" are more like dimensioned sketches. Back in the 80's Bazil Hartley used to have a column in Model Boats, and on one occasion he showed some photos of a similar engine by a friend of his from New York and gave a short explanation of how it worked. I liked the idea and came up with my own version.
I've just had a look at the sketches and realise that there were several design changes made as I was building. Unfortunately not all have been recorded.
I find I even have a set of castings left!
Malcolm
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Hi Malcolm thanks for the upload love the little engine and I can understand the mechanism after gawking at it for ages bit slow in the old age but still wondering why it was so stiff to move the gear bar as the camshaft and valve gear should not have had much resistance
Cheers
John
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Hi Malcolm,
Thanks for the information. Like John, I am also getting my mind around the mechanism. Given that the majority of components follow conventional design principles, it is the the relationship/gearing between the crankshaft and the eccentric shaft that is of particular interest. Can I ask, are you able to post details/sketches of that particular aspect?
John,
Please post any details of your engine as your build proceeds, as I and I suspect many others would be must interested.
I have no immediate plans to build such an engine as I want to concentrate on the "Marcher" build, but one such engine may be the next project. Although you have got your gears, this company: http://www.hpcgears.com looks like suitable supplier.
Ian
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Hi John
Bear in mind that it is over thirty years since I built this engine. Yes there should have been no stiffness in the mechanism, but having just run it on compressed air I think I know why I used the steam cylinder to operate the fwd/rev lever. When the lever is moved yo either fwd or rev position, the engine starts and the lever starts to move away from the correct running position and needs to be held in place. I assume to do this, the servo would be energised to prevent the movement and I thought that this would run the receiver batteries down. Hence the change to the steam operation.
Hope that makes sense.
Malcolm
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Thanks Ian made a start on the engine I don't use drawings just go along bit by bit as log as I have the bore and stroke worked out ,this one will be 5/8th x 3/4 " all done on my little Taig lathe.
The engine will be powered by a small yarrow boiler also building the tug Joffre so I am jumping from one project to the next so never boring (no pun intended.
Will keep posting as progress advances
Cheers
John
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That is a very interesting lathe John. Unusual to see the ability to move the tail stock laterally.
Simon.
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Hi John,
Thanks for posting. It was just as well you stated that the bore was 5/8' & stroke was 3/4" as the last photo of the cylinder block gives the impression that it's much bigger. Looking forward to further posts as you make progress.
Ian