Hello everyone.

I have been flying an stick kind of plane with a converted Mitsubishi 33cc

With a 16x6 propeller I was getting 8,000 RPM but not much climbing power

With a 17x6 It gets better

I tried this last weekend a 18x6 and while RPM´s goes down to 6,400 the plane behaves much better in the air with much more climbing power.

The question is should I try a 19x8 MAS Scimitar prop or would that be too much for a 33cc converted engine?

Thanks everyone for your help.

VÃ*ctor.

I think that would be too much prop based on the rpms you get with the other props. If you prop them below around 6400 rpms or so, they are down on power and the engine might get hot.

AV8TOR

Well, I guess i´m gonna have to find something to do with this prop.

Is it a proper way to scale down a 19 prop to 18 or 17 inches (Of course balancing the propeller again) or those this process woud really affects the pitch or performance in the prop.

Regards.
VÃ*ctor.

I have cut down propellors up to an inch before. Just make sure to re-balance as you said.

AV8TOR

I've got a APC 16.5x8 made out of a 18x8 prop that I trimmed down from an extremely minor prop strike... unless I told you it was trimmed you probably wouldn't notice, it behaves decent, hauls the plane similar to the 18x8 that it was made from, have about half a gallon through it so far.

The 18x6 is making about 1.1 hp at 6500

A 19x6 would probably turn about 5900 rpm

http://personal.osi.hu/fuzesisz/strc_eng/index.htm

The larger prop at a lower rpm, same pitch would be even slower. It sounds like you need a more powerfull engine.