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Stationary steam engine model

10K views 36 replies 10 participants last post by  CliffyJ 
#1 ·
As some of you know, I'm a total newbie to how steam engines work, but I've been modeling a stationary engine anyway. So thanks again to everyone who helped me with questions on prior threads.

Here's the state of the (computer) model design so far.

http://www.youtube.com/watch?v=OxZ361DxK50&feature=youtu.be

The Stephenson valve gear has been been quite the (interesting) challenge, but I think I've finally got something at least vaguely workable. It looks pretty chunky, but I need to make the parts 3D printable.

The intent is to make all the white bits with 3D printing, and cut the shafts from brass round bar. The screws are #0 and #1 lag screws from Micromark.

As for functionality, the gearmotor (beneath the "cylinder") is tiny; and if all goes well, it will drive a small grooved friction wheel that acts against the OD of the flywheel -- which is a square o-ring.

I've no idea if it will work at all, but I'll keep you posted.

===>Cliffy
 
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#30 ·
You said I made you drool :eek:
The quality of the prints is so beautiful! I have to mask everything with layers of filler and paint, but this comes right out of the printer?
This makes me wonder if it would be possible to run a printed steam engine, stationary or not, on compressed air ..
 
#31 · (Edited)
Thanks Peter, I'm very glad you liked it! Your work is tremendous, and I appreciate your thoughts and comments.

These parts are SLS-printed nylon from Shapeways, so yes, that's basically how they come out. I had to sand the cam follower rings narrower, because I should have modeled in some clearance. Also, since there's always a tolerance factor, I make all holes undersized, and drill them back out as needed. Otherwise, I didn't alter them.

Have you seen rkapuaala's SLS-printed metal engine build? Amazing. The part quality is wonderful.

http://forums.mylargescale.com/18-live-steam/42906-erection-drawings-0-4-2-t.html

I like your idea about compressed air op, that would be a fascinating thing to explore.

There's a hurdle to get over though, in that you need pressure-rated materials for piping, valves, boiler, etc. The sintered metal might have semi-sintered areas that you couldn't see. They might be brittle, there might be fatigue issues when repeatedly cycled, etc. I honestly don't know. And, certain things like valve sealing areas wouldn't be printed as smooth as a machined surface.

BUT, if you designed around pressure-rated products -- brass tube / valves / boiler / cylinders & pistons / etc. -- and used printed products for the rest, it should work. You might want to use printed metal for all the valve & running gear, because of the stresses involved with a functional machine. In my model, the flywheel is being driven by the motor in the base, and all the rest is just fake stuff going along for the ride.

Your idea is very intriguing though!

Best,
Cliff
 
#33 ·
#36 ·
Thanks very much Doc, it was great to meet you too, and I'm so glad you liked it. You remind me that while the ECLSTS is done, I do need to complete this thing in the sort of near future... so I'll take that to heart.

Cliff
 
#37 ·
Thanks Mike.

Depending on what figure you put next to this, it could be 1:29. There were so many sizes (bores, strokes, flywheel diameters, manufacturers, etc.) that the only giveaway I think would be the steps and the reversing lever. So maybe those elements could be modified to suit.

Cliff
 
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