Multi Cylinder Radial Engine.

[ebeneezerParticipant @ebeneezer]

Hi having a lathe, milling machine, and rotary table. I have plans to try and build a radial engine.

I have in my possession several Cox 0.049cu.inch engines, my thought is to attempt to build a multi-cylinder Cox engine from these.If anyone out there has drawings, ideas or words, of wisdom It wold be truly appreciated.

I have plenty of machining experience but little experience of the workings  of engines. Only single cylinder reed valve engines. So any comments would be appreciated.

Cheers. Mike.

 

 

 

[bernard towersParticipant @bernardtowers37738]

It would be interesting Mike, the cox is a two stroke so problems with the pre charge in the crankcase not saying it cant be done but how??

[JasonBModerator @jasonb]

Blower in the crankcase as seen here

[bernard towersParticipant @bernardtowers37738]

NOT a first engine project

[JasonBModerator @jasonb]

But is a radial a first project? The blower parts on the right are probably not any more difficult than the crankcase and all the conrods etc. Maybe try your hand on an opposed twin first. Or one of the inline “Hex” engines, plans in Model Engine Builder back issues

[petetwissellParticipant @petetwissell]

There are a few possible approaches to making a radial based on the Cox 049 engines.

The simplest is to arrange a number of complete Cox engines in a circle, with the crankshafts geared to a central propeller shaft. This would require some off the shelf gears and a couple of mounting plates.

Another possibility would be to make a multi-cavity crankcase, still using the Cox crankshafts and enclosing gears and a common shaft as above.

If you want to make something more like a conventional radial with master and slave rods, you will need to interface the rods to the Cox pistons (swaged joint to a ball end rod) or make your own ringless pistons to fit the Cox cylinders, with very tight tolerances! You will also need to arrange a secondary means to generate the intake charge pressure.

I happen to have a side project ongoing – a 2 stroke radial which uses displacement under each piston seperately to generate induction pressure. I’ll go into more detail on a seperate thread if anything comes of it.

The first two options are relatively simple to manufacture and most likely to result in a running engine.

Anything else is within the realm of experimental and will be a test of patience.

[duncan webster 1Participant @duncanwebster1]

If one had a radial with an even number of cylinders, then diametrically opposite pairs could act as charge pump/power cylinder combinations. Plumbing might be a bit complicated. Alternatively, half the cylinders could pump up a toroidal  receiver (or even the crankcase) which fed the other half. Getting a long way from the original post!

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