I have a GMS120 2 stroke that turns an APC 17X6 around 9300 rpm on ys20-20 fuel.

That is right in the 4stroke rpm range and with similar power to that size 4stroke.

It revs quickly and runs great.

It would hover my 10lb funtana easily.

Only problem is that it sounds like a 2 stroke.

Larry

Torquewrench- if you want that suck, squeeze, burn, blow thing we should switch to turbines!!!!! 8*P I've been tempting 2 guys at the field a lot about getting into that. No luck so far.


Sport Pilot- it is a sad situation if an engine has to limp around at 8K for noise limitations when it is supposed to buzz at 15K. Another reason for 4 strokes!

The OS 1.4 and Webra 1.6 RE two strokes were not intended to run at 15,000! They are set up by the manufactures to run at 9,000. Even if set up for speed I doubt they would turn 15,000. The larger the engine the more difficult it is to get high revs without something breaking. Look at Dub Jett's engines. Their larger engines do not get max power at 15,000, but several thousand RPM less. Even in the 80's when pattern engines were limited to 10cc they were turning in the 9,000's with props such as 12x12 and 13x10 two blades. Two stroke engines mind you. They were getting about the same power as most of todays .91 four strokes.

Dirt bikes are mostly going to 4 stroke engines. The reason dirt bikes used 2 storke engines for so long was a matter of cost and technology... Now 4 strokes are practical for small dirt bikes, and they are outselling the 2 strokes....

4 stroke engines are clearly better than 2 strokes, especially when using gasoline. Less fuel usage, more reliability, and longer lives.

This Thread has gone completely Off Topic and has outlived its usefulness.