David,


I am told by someone who got Bolly Clubman 10.5x7 props from me, for his Webra .50GT, that the engine is overloaded with this prop size.

The MVVS .49, with the tuned silencer, spins this size and other larger props with ease (12.25x3.75 is large), at very respectable RPM levels.
13,600 on an 11.5x6 Bolly is a typical number (5% nitro, 20% oil mix).

It is only on small props; 10x7 and smaller that the Webra excels.