I care about RPMs and I think it's a little harsh to insinuate people are wasting their time "getting hung up" on RPM's. After all it the common denominator in thrust comparison.
400 rpm is a great deal of RPM... and thrust. Don't think so? Throttle trim your servo down about 400 rpm and enjoy the loss. It's the latest craze...
The poster asked about rpm's cause he wanted to know where he stands and where he might stand with another exhaust and prop. Sounds like he wants to maximize his power on his airframe... How silly huh?
Come on DP... your post had some good info but sure was "fatherly". You in a bad mood today?
ORIGINAL: desertpig
Unless you are trying to power a Comp-Arf 2.3 or heavy pig don't worry about the RPM. This engine will produce enough power on a stock muffler to haul a 16 pound plane into space. Tune the engine by ear to the max RPM, back off about 200 and forget about it!
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The DA50 has more power than you will probably ever need ... I am not sure why so many people get hung up on getting every last RPM out of it.
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I never tach my engines, total waste of time. If my engine starts great, has excellent idle transition, top end, runs cool and takes the plane straight up out of sight... who the %^%$ cares what the RPM is.... !
DP