Originally Posted by
049flyer
I think 14,000 rpm is a bit high for stunt. 10,000 rpm is closer to what I look for before launch, sometimes even less, 9500 for my Fox 35 mounted on a Bi Slob. I normally launch at a very rich 2 cycle or even richer 4 cycle.
The stunt pattern requires climb capability similar to RC 3D flying, therefore, brute horsepower is NOT what I look for in a control line engine. Torque is what you need to turn long, low pitched, climb propellers. Consistency is second which often means awesome fuel draw from smallish venturis. Much different power profile than RC.
Yeah a FOX .35 with a 10 x 6 is designed for 9500 to 10,000 rpm...
but 14,000 with a 4 pitched prop ought to be doable with most any piped schuernle ported engine and would give 5 second range laps ..which I believe is what the Top Pilots shoot for.
In this case I understand that the pipe is supposed to act as a rpm limiter to keep the model from speeding up on the down hill side of the manuevers.