ASP180 4 stroke Prop Dilemma

Briefly here is my conundrum. I have a 180 4 stroke (30cc) laying around. The model I planning on using it in would need a pusher prop. Previously the engine had various 2 blade props in the 17 - 18 range (Super Chipmunk). But the present project requires a pusher and three blades. Possibly 16 x 3 x 12? But where from? Large IC props in pusher format are like rocking horse s**t.

If I can not solve this little problem the alternative is a 2500W electric motor, HV 120 ESC and a pair of 5 cell lipos, all extra expense.

I've seen a propeller system on the Internet. It has an alloy hub, available in three and four blade types. Has the advantage of selectable pitch settings via a supplied key, the blades come in various lengths and styles. Just wish I could remember the maker, think it was German. Pretty sure you could find it on Google.

Phil F51 told us of his dilemma

If I can not solve this little problem

How about looking into having the 4 stroke re-timed to run "backwards" which would then allow you to use a conventional tractor prop as you would if you went electric?

Brian - I think your talking Ramoser Vario props. Got one already for the PC21. Good but expensive. But they are not "pushers".

David - Now that's an idea if possible. I would think the cam shaft would be reversed somehow. I'll speak to Just Engines later see what answer I get.

Phil informs us that

I would think the cam shaft would be reversed somehow

I had assumed that the inlet and exhaust cams would be driven separately as in Laser engines, if both cams are on one shaft I fear that the idea will be a non-starter (in both senses of the hyphenated word!).

DavidTappin wrote: I fear that the idea will be a non-starter (in both senses of the hyphenated word!).

After wasting another afternoon of my life surfing the Net till my eyes drop out I have come to the conclusion that at present this project is dead in the water. I'll hang it up back in the hangar again. The engine definitely needs a 16 inch or maybe 15 inch three blade pusher prop. I may nick all those new servos back out of it too.