Ideas for a small marine engine

[Roderick JenkinsParticipant @roderickjenkins93242]

While I can’t disagree with any of the comments above, if the OP has no experience of lathework then I suggest that building a Stuart 10V is an excellent start simply because there is a book that describes exactly how to do it:

https://www.teepublishing.co.uk/books/stationary-steam-engines/building-a-vertical-steam-engine-from-castings/

There is also a plethora of Youtube videos describing making a 10V which may (or may not!) help.

Anyway, good luck to Andy, the important bit is to build something!

Rod

 

[Roderick Jenkins]

On Roderick Jenkins Said:

While I can’t disagree with any of the comments above, if the OP has no experience of lathework then I suggest that building a Stuart 10V is an excellent start simply because there is a book that describes exactly how to do it:

https://www.teepublishing.co.uk/books/stationary-steam-engines/building-a-vertical-steam-engine-from-castings/

There is also a plethora of Youtube videos describing making a 10V which may (or may not!) help.

Anyway, good luck to Andy, the important bit is to build something!

Rod

 

Putting differences of opinion as regards ease of building aside unfortunately the 10V is a bit limited as a controllable engine in a model boat.  It is on the tall side and maybe even heavy for some small boat applications, it requires additional reversing gear and hence another servo and channel to reverse but, the biggest challenge is, being single cylinder it cannot be considered as self starting.  You therefore have to also consider additional barring gear to ensure starting or accept a continuously running engine.

The best option to use a 10V in a model boat is to use a controllable pitch propeller but then you are still using steam when the boat is stopped and, from my own experience of running a controllable pitch propeller driven by a 10V, you are also better off using speed control of the engine to minimise this steam waste.  I would suggest such an arrangement is a challenging model to operate for someone’s first steam boat.

 

[JasonBModerator @jasonb]

Well after exchanging a few PMs and emails with Andy I feel that a new build thread like some of my others with a set of FREE drawings provided may appear here fairly soon.

He liked the look of the quickly put together Vee Twin that I posted which used some of the parts from my Bassett Lowke. Now that I know the engine will run on steam and be put to work I have played about with the design some more.

These images show it in it’s “barstock” form with mostly square edges. Builders could stop there or I will go on to knocking off the corners and adding a few more details to make it look more like a traditional engine from castings.

Some of these engines like the Blackgates one have a lot of unsightly pipework, others like the Stuart connect everything together with a series of drilled passages and that is what I will be using. This image gives an idea of some of the drillings as I have made the standard transparent. You can also see the internals of the regulator/throttle which I have used straight cuts for rather than curved so it can be made without a rotary table.

Watch this space

 

[JasonBModerator @jasonb]

Richard Simpson. What is the current preferred method to get drive from the engine to the prop shaft? Is the old two pins in the flywheel still used or would it be better to have a longer crankshaft to a universal joint could slide on and be held with a grub screw?

[BazyleParticipant @bazyle]

Jason wrote “You can also see the internals of the regulator/throttle which I have used straight cuts for rather than curved so it can be made without a rotary table.”

That is a revolutionary idea that would simplify the making of countless designs – brilliant.

[JasonB]

On JasonB Said:

Richard Simpson. What is the current preferred method to get drive from the engine to the prop shaft? Is the old two pins in the flywheel still used or would it be better to have a longer crankshaft to a universal joint could slide on and be held with a grub screw?

Jason, From what I have tested over the years the twin cylinder, double acting oscillator is by far the most common engine that modellers put into model boats and, I think, with good reason.  In ‘V’ form or in line arrangement they can be selected to provide simple, reliable high power to weight ratio power plants that are easy to operate and maintain.  Your drawing is an excellent modification on most standard drawings and manufactured units with the straightened channels in the control valve.  The biggest challenge for most inexperienced machinists, apart from the piston and cylinder, would be the accurate drillings in the entablature but that shouldn’t be beyond most modellers.  I have a John Hemmens ‘V’ twin Richmond in a North Sea Coaster because it was the only engine I could tuck away down in the short stern:

As for transmission, the biggest challenge I see nowadays is the poor quality of the ‘Huco’ type couplings.  At least for steam propulsion the revs are low so the out of balance problems that challenge the performance boats is not an issue but, what frequently is a problem, is the fact that the splined fit between the inserts and the plastic joint pieces are too tight.  If the splined fit was as good as it should be then there is no reason why the shaft insert cannot be secured to the shaft and the engine insert secured to the crankshaft and the joint simply slid into place when assembling.  This is exactly what I do with this coupling because the engine insert slides in perfectly.  Its still a bit fiddly to fit with all the cockpit and decking in place covering everything combined with the fact that it is a double coupling but a bit of patience and a pair of tweezers and I can drop the engine in easily enough:

For ease of operation, especially for anyone new to steam, the idea of a ‘package’ steam plant on a single base making it quick and easy to remove is always worth considering, such as these from Miniature Steam Models:

If you can find a Huco coupling with a nice sliding fit then they work well, as I did with this one, enabling the whole plant to be removed in a few minutes:

Frequently though, if a Huco coupling with a nice sliding fit cannot be found the two pin method might be the easier way to go:

Again this model has a steam plant in a package arrangement, this time an old Cheddar Puffin plant, which can be lifted out in minutes:

I also used the pin method in an installation where there was very little room for any other type of coupling:

There are other couplings used such as the dog bone type:

And others which don’t lend themselves to such easy disassembly, such as solid rubber inserts:

I’ve even seen, and used it myself on low powered electrical installations, a short length of silicone tubing.  Even when the two ends do not match Huco type inserts can be fitted and then a short length of silicone tube with a reasonably tight fit slid  over the splines:

[JasonBModerator @jasonb]

Thanks Richard, I think I will allow an extra 10mm or so on the crank length so a coupling could be used, with a note to the builder to adjust as required.

Well a bit more playing with Alibre and I think I have a design I’m happy with. I’ll go into more detail in a separate thread but adding up the costs it looks like just under £50.00 for metal & fixings and another £10.00 to cover the O rings & springs so my 1/3rd to 1/2 the costs of commercial kits was about right compared to the smaller Stuart kit at £169.00. As for tools I think the only addition to what would have been needed to make the Stuart is a countersink bit but even that is optional if the engine is to sit on a couple of bearers in the hull or flat on a shelf.

[Richard SimpsonParticipant @richardsimpson88330]

Lovely job Jason.  I think the 10mm extension is a good idea and certainly gives the modeller flexibility.  Would it be possible to raise the port face on the entablature slightly to allow for lapping of the control valve?

[JasonBModerator @jasonb]

I’m one step ahead of you. That was one of the options once the basic shapes have been cut, I’ve also raised the regulator valve face.  Though the whole “Y” shaped standard is quite small at just under 50mm high you could quite easily lap the whole face of a bit of wet n dry on a flat surface. certainly smaller than just the port face on some engines I have made.

It is not raised by much as I wanted to give the builder a decent distance between the various drillings, putting them closer would allow more to be machined away leaving a higher raised area.

 

[Richard SimpsonParticipant @richardsimpson88330]

That should do it nicely!

[Martin CurrieParticipant @martincurrie]

Hello

I have redesigned & drafted plans of Bogstandards engine at 2x the original scale. If anyone wants free plans, ping me a message with your email address and I’ll forward on a set of drawings.

I had posted a thread on paddleducks some time ago…

 

Martin

[andyp123Participant @andyp123]

Jason, thanks for the design, it’s looking good, when you have costed the material, do you list what is needed? There is a place in Macclesfield (not far from Buxton called Macc Models and i think he sells material like this.

Andy

[Thor 🇳🇴Participant @thor]

Hi Andy,

Macc Models is where I get most of my metals from for building my small steam engines. Good luck with your project.

Thor

[JasonBModerator @jasonb]

I will do a basic shopping list as well as a bill of materials. I’m not keen on bills of materials myself as I feel going through a new set of drawings is a good way to get to know the design, think about how you personally will make the parts with what tooling you have and make suitable allowances for chucking/holding and additional tooling required but it can help a beginner to see what they need..

I priced the materials based on M-Machines pricelist as they are my usual source and carry a big range of materials and a lot of that in metric. They also have all the barstock so a one stop shop. Macc don’t have 3  of the materials, two cold be substituted with a change of material or going imperial but I can’t see an alternative for the third. As that item is what the main standard, rear bearing block, pistons and regulator will come out of it is probably the main piece of material needed for the engine. Though nothing to stop anyone searching around or making substitutions for what they may have to hand. Though as they do run an advert in the mag it is nice to support them with a purchase.

[JasonBModerator @jasonb]

I have started a new thread describing the build of “Kelsey” a V-Twin oscillating engine here. Comments and questions welcome. As is anyone who wants to build one, plenty of time to get one made for that Christmas gift.

[JasonB]

On JasonB Said:

I have started a new thread describing the build of “Kelsey” a V-Twin oscillating engine here. Comments and questions welcome. As is anyone who wants to build one, plenty of time to get one made for that Christmas gift.

Jason is a prolific builder of small engines of all types and his house must be full of them.  Worth a look, but hard to find, despite many build threads on here.  (A search engine problem.)

In post #823601  Jason announced a gallery, making it easier to see some of what he’s done. It’s incomplete, and I hope he will add more engines later.    Has Kelsey, Eclipse, Clarkson Horz, Chuky and Muncaster.   Get to his Galleries by clicking on the Traction Engine picture above his user name.

Don’t expect ready to go plans and instructions: the build details are scattered across the forum, and have to be searched for.  All made from stock I believe – no need for castings.

Dave

[JasonBModerator @jasonb]

There is a clickable link to the build thread in my post above yours. That link includes the method to get to the gallery and direct links to what is contained within.

The Gallery mentioned is specifically for items relating to Kelsey hence it’s title “V-Twin Kelsey” It is also complete as of the time of writing. I will not be adding other engines to it.

I do give detailed plans and instructions, and put them all under the one single thread for the specific engine rather than “scatter them about”

Some of my builds with drawings detailed here do make use of commercial castings, usually in the form of the flywheel.

[JasonBModerator @jasonb]

As the forum gallery is not ideal for updating the drawings, they can now be found here along with the bill of materials.

[andyp123Participant @andyp123]

This is great and I am so pleased to have found such a supportive and encouraging group to start me on the way. Thanks Jason, i really appreciate your help.

Andy

[JasonBModerator @jasonb]

Your Welcome, hopefully you have found the build thread and link to the drawings.

Anyone else fancy having a go? don’t be put off by page 3 of the drawings. It does look like a lot of holes but I will break them down over several more drawings to make it easier to follow. Infact there are only 4 more holes than you would have to drill on a Stuart V twin and they are the 6mm hole sthat establish the internal corners of the overall shape and are not critical.

Starting to look a bit like an engine now

[Author]

Posts