Run an .049 on steam?

Ian, yes that thread is the one I referred to early in this thread. Thanks for the link, I just read it again. Unfortunately, he never returned to show us a working engine. My idea is basically the same as his, but my valve will be miniaturized to fit ON the engine to make a nice, compact unit.

Engine mods

I chose a Babe Bee engine because the crankshaft neck is thinner. This will give me more room for the flywheel/pulley/eccentric. Also, a 'horseshoe' backplate, the one with no fuel tank was chosen. The tank or backplate in this case, has a projection that goes into the crankcase and appears to give at least some support to the con rod to keep it from moving off the crank pin. This thing will run nowhere near as fast as a fuel engine, but still, looks like a good idea.



I managed to hack the needle valve out of the housing. This will be cleaned up and the screen glued back in place, just to keep swarf out of the crankcase. I think the needle valve may make an oiler one day. This model is all brass, so it came out of the housing nicely.



I sawed and filed the swaged metal away from the glow plug and the plug itself came out easily.

OK, a question for you guys. Reading that linked build again, I see that he blocked the exhaust ports. I think that might give me a bit more power as well as directing the steam to the crank case. If I do oil the steam, that should lube the whole engine that way. The transfer ports become the exhaust ports in this case. Good idea?

Ken , yes the conrod is kept on by the insert that holds the reed , you could have heated the backplate up with a hair drier and snached the or levered it out with smal. side cutters needle valve assy. out . Is this going to be a one or two piece unit for the engine and then steam??

I wasn't sure how the needle valve assembly was held in, so I carefully started sawing with the jeweler's saw. Once I found that it was for sure brass all the way through, I just hacked and chopped the remaining plastic out. I will file it smooth.
I'm not sure what you mean by 'one or two piece'. It will have a boiler to supply the steam.

Now I am having second thoughts on the slide valve design. I really wanted a rotary valve design and now I think it will work, with the original crank. I do want this to be something that others can make, if I can make it work. By using as many original parts as I can, hopefully that will be the case. So, what I am thinking is this...

A rotary valve in a simple steam engine is just a flat on the crank, with steam ports in the crankshaft housing. All must be timed of course. Since my cranks are probably standard (I want to take one out tomorrow), they should look like this.



That won't work. A shaft with one diameter end to end is what I need. I know that they do make those, but I want to use standard stuff that anyone can get off ebay. An entire engine for about 10 bucks would be my goal. So... I think I will grind a proper flat in the center of the crankshaft, then soft solder the undercut section of the crank full, flat and all. Turn the solder round and to diameter. Then I can file the solder away, down to the flat. Should work. I don't have to worry about ruining the temper of the crank, it won't be running very fast. Famous last words...

More later.

Update. This is the engine I was going to build for the locomotive. It has a rotary valve. Note the similarity to the .049 engine structure.

Ken, the steam engine I made was a fiasco. Not only the fact that the stroke is too short to give inertia to the, in this case too small a diameter flywheel, but also the steam delivery to the valve is wrong. The steam delivery should have been on the side of the plunger and not axially. When the plunger is moved up by the crankshaft and excentric, the steam pressure acts against this movement, so not good at all.

The engine in the picture you posted above is very cool. You notice also the important length of thestroke compared to the bore. Steam engines do not only rely on steam pressure but also on the steam expanding in the cylinder which is a great difference with compressed air. All this gives immediaty power to a steam engine that doesn't need revs at all to be powerful. It's like a Stanley Steamer when manoeuvring: that car can run easily 1 to 1,5 meter from stand still with 1 engine stroke.

When I was sailing in my younger years, I built while at sea, a V twin oscillating single action steam engine from scratch, also square and I had to mount an enormous flywheel to have it run smoothly, if not, it just shaked apart. It's still at my parents home in Belgium. I'll be there over the week-end and I'll bring it with me if I find it.

I hope you'll succeed in making a workable steam engine and for a train, that will be very exciting. Plans for making a Heisler? I got one in HO scale from Rivarossi, a wonderful machine!!

Lieven

Lieven, thanks for the update. For some reason, I can't click the 'thanks' button in replies.
I too hope this works. I realize that the little engine isn't really made right for steam use, but I need to try. I am looking again at the 'pin and ball' valving like CO2 engines use. I need to go get my little vise and disassemble a crankshaft from an engine. I want to see what I can figure out with rotary valving.
I do like Heisler locos, but no plans for one. This critter I am working on now is just a winter passtime and a way to stay sane while dealing with several feet of snow around me.  
If you find that other engine, please do post pictures and more about it.

Oh, the plans for that engine I posted above are free on the 'net.

It took me ages to find this. I find the search engine difficult to use.

This is one of my miniatures but I make steam engines all the time - usually from Stuart Kits or Bengs where all materials are supplied but need machining.

https://www.coxengineforum.com/t4047-minature-steam?highlight=steam+engine

Thanks Ian. You have neat toys. It is good to see that there is interest here in steam. I was afraid I was making a pain of myself.
I just got a crankshaft out of an engine, successfully, and am studying that bit of metal. I also see that I could sleeve the Cox cylinder with brass, hmmm... Too many ideas.

Look at this pretty!



The flywheel arrived from Bob today. He also sent some extra long prop screws. Thanks again for the generosity! This flywheel will be perfect!

Personal opinion, I don't believe that flywheel will be heavy enough for the steam engine, considering the relatively short stroke compared to bore diameter. Fine for high speed internal combustion, but at odds with a typical steam engine design.

I have a couple of tricks up my sleeve. And, a nice chunk of round brass in the shop. I can probably make the flywheel heavier if needed.