Here is what it looks like when made, a fully controllable fwd/rev radial engine, designed to push a model boat along.
And here is mine, stripped down for refurb. Very few parts indeed.
There are a few things to point out on mine that might be relevent.
You will notice that I have fitted viton piston rings, don't bother, on an engine this size it just causes problems with friction.
I have made much thicker walled cylinders, this was because when I dropped the first one I made, one of the cylinders easily dented and so the engine was scrapped, as it just would not run on two cylinders.
The major mod, which I think is essential, is if you look at the cylinder head on the one at the front, you will notice a bolt in there. Rather than cutting the line to the cylinder and putting a piece of silicone tube on it, this allows you to time the engine much easier, and looks better as well.
As usual I silver soldered mine, but the plans called for soft soldering. I reckon this engine, if only going to be run on low pressure air could be made mainly out of ali and stuck together using a Loctite engineering adhesive.
It runs on a breath of air (5 psi) if made right, but I have had it on 60psi wet steam and it really motors along.
I must root thru all the other old boxes in storage to see what I can find.
BTW this is the sort of job that requires an easy tube bender, again I have plans and used in conjunction with Bob's groove cutting tool could easily be fabricated. Usual thing, send email.
John
