Opitec hot air engine

Has anyone made one of these? I believe they were supplied either as kits or drawings.

Opitec is still in business, but they can't help with drawings. Does anyone have a set they would be prepared to let me have a copy of please?

Dave
The Emerald Isle

Dave, is this the one you're after? **Opitec Hot Air Engine**

Andy

Edited By Andrew Holdaway on 05/12/2016 21:52:36

Yes, Andy, that's the one. Many thanks.

Dave
The Emerald Isle

There are one or two modifications I would suggest. (1) instead of brass tube for the main crankshaft bearings I would use ball bearing races. (2) I'm strongly against using an aluminium piston in an aluminium cylinder. The cylinder could be bored out and a steel liner pushed in with some Loctite retainer, thread lock would do, and a cast iron piston.

Ian S C

Also note Verdranger sehr feine Stahlwolle translates to steel wool, this is the displacer/regenerator. You don't have to use a test tube for the hot cap, this is best made from stainless steel, but ordinary mild steel will work. If you are lucky you might find that the steel case of a dead Nicad battery might fill the bill. The casing on the left is from an alkaline battery, the + tit is on the case.

Ian S C

I built one of these when I first had a lathe. I couldn't get it to run, and - at the time - couldn't find anyone on the web who had either.

Now I've learned a few tricks, I might have another go. Ian's suggestion to use ball bearings rather than a plain bearing would be a very good start. I don't remember my kit using an aluminium piston in an aluminium cylinder, but that's the sort of thing I wouldn't have noticed back then!

I don't want to waste time flogging a dead horse if the design and materials are flawed. Can anyone confirm they've got one of these engines to run?

Thanks,

Dave

Edited By SillyOldDuffer on 05/01/2017 12:38:47

Dave, I don't build to plans, but it should go, especially if proper bearings are used, I don't think these things are designed by anyone with engineering knowledge.

Apart from the fact that you can see the displacer moving, I'm not over fussed with the hot cap being made from a test tube. Also I prefer a hollow cylindrical displacer, I'v tried the steel wool, and find it more trouble than it's worth.

Rule one, minimum friction, and two, minimum leaks. It then should go.

Ian S C

Thanks Ian. I'll give it a go. I suspected the steel wool was wedging, and hadn't thought of a hollow displacer.

Cheers.

Dave

The worst one I fitted with steel wool was a vertical BETA motor, the steel wool broke up , and little bits dropped down on the piston, then got wedged in between the piston and the cylinder.

Ian S C