Originally Posted by
Mr Cox
When I saw their performance some ten years ago I totally lost interest. The AP 09 seem to be at least 1500rpm below other regular .10 engines on a 7x4 prop... Does the carb have any low end adjustment? Here is a video from NoNofulton active on RCU (1/2A forum) at the time;
http://www.youtube.com/watch?v=ceP0OTrcbZw
Compared with the OS Max 10 FSR (reference Peter Chinn's May 1983 Aeromodeller OS .10 FSR R/C engine test,
OS Max 10 FSR, it obtained about the same RPM's on a 7x4. I gather that the OS Max .10 FSR, FP and LA are more or less on par with each other. Perhaps on your hotter .09's - .10's there may be a difference, but results seem to so the engine is sufficiently powerful for a sport engine. As shown by others, the engine can be made to shine when used with a less restrictive muffler like a Saito 4 stroke. Also, the .10's are slightly greater in displacement versus this .09.
Considering that the engine retailed for less than half the price of others, and has successfully powered various sport aircraft, as I have observed previously, match an engine with the right airframe and it will perform satisfactorily. Any engine will suck if poorly match to an airframe. Each flier has their preferences for engines and will gravitate toward certain ones as favorites over others.
I could be wrong, but I gather that a good thing about this engine is it is a continuation of the Sanye line and not merely a copy or re-licensing of another's engines. A better muffler design would have had a better performing engine, but then economics were considered. The muffler is compact and seems well suited to use in either an RC or CL profile design fuselage mounted "pancake".