Dave, here's what I did for Gale Enstad's 1:27 and some change, TT Pro 40.
Mounted engine to the plane. Ran 1 tank with a 9x6 APC prop on the ground,,, rich-lean-rich-lean,,, etc.
Next tank full, I set the engine to a fast 4 cycle speed,,, I don t know what RPM it was because I don t use a Tach.
Launched the plane,,, climbed up HIGH,,, and dived for the ground. I did that several times.
Race needle setting was approx 1/4 back from peak rpms,,, the rest is H.O.F Racing History
BV