ORIGINAL: les40
THe OS 91 FX turns a 14X8 prop at usable 9500 rpm and the engine only weighs something like 19.6 oz. My Saito 100 4 strk turns the same prop at a usable rpm of 9000 (using 30% nitro) and weighs 20.9 oz. I guess 2 strks still have the edge when it comes to performance.
If I'm wrong let me know. I'm a 4 strk fan but have been wondering which technology has the best usable power to weight ratio. To me it still looks like the 2 strks take the lead.
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When it comes to all out power, the two-stroke is still king.
However, in flying model airplanes in a sport manner and several other manners, peak horsepower per displacement unit isn't the only criteria by which to judge an engine. As others have stated most eloquently.