Stuart Triple Expansion Engine


New member
Is it a good steam engine design to machine the cylinders out of 6061 aluminum with 303 stainless steel cylinder liners?
I'm designing a steam motorbike and any weight savings is always best.
I have access to Stuart drawings for building any size engine.
I need around 2-4 HP.
any constructive advice is much appreciated.:confused:


Sounds like an interesting project.

There are a lot of model builders on this site that should be able to help you out where needed.


New member
You would do better looking at a larger design to start with if you want that sort of HP, although I have seen the Stuart scaled up it lacks a lot of refinements you would find on a larger engine such as condenser, single point oiling, feed pumps, etc.

This is more the sort of thing but I don't think even that will develope the HP, its about 12" long.



New member
Drawings and castings from Reeves, they also have several twin cylinder compound engines

There is a guy doubling up a stuart triple on HMEM


---------- Post added at 05:58 PM ---------- Previous post was at 04:59 PM ----------

Further to the Horse Power question if you look at Reeves "Commander" engine the spec for that is 50mm and 75mm bore x 60mm stroke and that only just gives the minimum you require at 2.3HP on 150psi at 500rpm. It is also about 24" long, 18" high and 14" wide.

You are going to need a lot of room in that frame by the time you have a suitably sized boiler, water & fuel storage, gearbox and clutch, etc.