Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

   Here are some photos of an engine that I have had for many years (7 or 8 I believe) and have been meaning to post here, just to share but also to see if anyone might know more about this type of engine in general. I do know that there was a commercially made two cylinder "valveless" engine, variously referred to as the Bowman Luton or Luton Bowman or Bowman Bryant, that was marked "BL" on the crankcase (I can add some photos of that one maybe later, from the web). They dated from the late 1940s into the 50s. I have never been quite able to pin down the exact specifics of how they work, but it involves slots cut into the cylinder walls and pistons that rotate in a ball joint and engage the slots such that one is the intake and the other is the exhaust.

   I acquired this from a fellow in England who was a collector of all sorts of antique scientific and technology artifacts (he did not in any way focus much on steam engines in particular). He had been told, or had concluded on his own, that this is a valveless engine of the same basic type, and tested it using a CO2 tank, he said that it ran, but at a pressure (in "bar") that I calculated was close to 160 PSI! I have never really tried to run it, the most I had available then was 40 PSI from an air compressor (and then only for a few seconds); that failed to make it run (maybe I saw a bit of action for that few seconds).

  This is certainly old, at least as old as the 1950s I would guess, and it would seem that it has seen quite a bit of use. It is beautifully made, with the nickel-plated connecting rods and crankshaft moving like a fine watch, super-smooth and precise (each piston is 1/2 inch diameter). The base is a 7/8 slab of steel with a hatched pattern that I assume is meant to replicate the floor of a marine engine room. Has reversing gear lever and some other bits that are a mystery. I believe that this was purely an exercise in model engineering and was never intended to actually power a boat.

  It also came in its own custom wooden case, with a little drawer that holds a set of tools, and two different steam pipe fixtures that screw into the main intake port. Whoever made the engine had to be a very skilled machinist I would assume, but they did not take the same care with the box, which is pretty crude (assuming that the same person made both).

  The strangest thing about this engine is the smell that came with it. Anyone old enough might recall the time when military surplus stores were pretty common, and they sold actual used surplus, and they had a very distinctive odor (these days, it seems they sell mostly unused items). Not a bad odor really (to me anyway), but this engine (mostly the box) had what seemed to be the concentrated equivalent of about 10 stores worth of surplus fragrance! So strong that it would fill up an entire room in 10 minutes. It took me about 3 or 4 rounds of scrubbing it with different soaps outdoors to finally get it under control, drying it outside after each round. Now, the smell is confined only to the box, and it is not overpowering. [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ]

   I now have a boiler that can keep up a steady 60+ PSI, and maybe the use of steady expanding steam as opposed to merely compressed air might help, although I can't see that if it took 160 PSI to run it previously. But the previous owner never tried anything else. I need to check to see if I have the right combo of threaded connections to try.

This is a fascinating engine!!

Thanks for sharing here!

Gil

Yes the automobile Willys Knight did have sleeve valve engines.

  Thanks to all for your comments and compliments. I agree that it since it does turn over so smoothly, and is so small, that absolutely it should run on low pressures, but like everyone else I just don't know exactly how it is supposed to work. Trying to take it apart is not anything that I would care to take on, but perhaps fiddling some with the various controls while having it hooked up to a steady pressure source would help. Honestly, I never really tried to do much with it at all, it has just been a nice display piece, and this motivates me to explore it further, as I always have intended.

Keep us posted on your experiments and observations please!