Strato, Irrespective of centrifugal force being non existent in the theoretical sense, you cannot deny the fact that having a monster spinner on your engine does not get affected by it's on inertia, and in my expericence with plastic spinners some form of deformation.

Sorry, but I agree with chuck on this one, I've been playing with engines a LONG time, and even our pylon motors would be hard pressed to clock over 21.

Here's a tip, record it's sound and by using a pitch tach, see what you get. You might be suprised!