Mark,


I agree with Dave about the balancing of the prop and the spinner.
About the make of the prop, I do not, however.

Master Airscrew black GFN props, up to 11" diameter, may spin a bit faster than an APC of the same size, or a +.5" Bolly prop. But their thrust and model performance is visibly inferior.

The Scimitar MA is much better, although the RPM will be lower.

The larger 'Four-Stroke' MA props, 12" and larger, are a real burden on the engine, compared with APC props of the same sizes. But they are somewhat more effective.


You did not write the pitch of the 11" prop that you used and the make of both.