Originally Posted by CubedRoot
Hmm... For some reason I thought they dyno'd all their engines before they sent them out.
Not everyone operates a dynamometer. Most small aircraft engines get run on a simple test stand with a calibrated club prop. The point is to run it and look at temperatures, pressures, etc, not tune for max HP. If it will reach a given RPM while turning the club designated for that engine model, it is assumed to make rated power.
The photo above (post 12) is a test stand. Below is the test stand currently in use at Continental Mattituck:
Barrett, Lycon, and Sky Dynamics all run dynos, but they're all different.
Barrett runs flat motors on an old school Kahn shaft drive water pump. When installed many moons ago, I'm pretty sure it was the first at an independent shop.
Barrett M-14s go on a torque reaction stand, in which the entire engine and mount can rotate on a very large central spindle. The rotation is constrained by a load cell on an arm, which converts strain to an electrical signal. Engine load is a constant speed prop.
Lycon appears to run flat motors on a similar torque reaction rig using a constant speed prop. Sky Dynamics has two torque reaction rigs, with load provided by a shaft driven oil pump.
I'm not sure where Titan's dyno is right now. It was AWOL from the new Fairhope facility when I visited in November. I'll check again next week.
Anyway, don't assume your HP was actually measured. And even when it is, all dynos are not the same.