Prop question?
 

Can a prop fly faster than its calulated speed?

RE: Prop question?
 

No, even if considering an ideal environment (no draggy airframe/engine, no air resistance) the theoretically calculated speed would be the best possible one.

From experience a very good speed setup reaches about 90% of the theoretical prop speed at given rpm (rpms of an unloaded engine during a powerdive derived from Doppler effect measurements).

Boundary conditions are:

- low drag airframe supporting the engine/prop combo to unload with ease after the first dive
- low drag speed prop designed for a certain rpm and target speed
- an engine swinging the prop within its highest efficiency
- preferably subsonic prop tip speeds
- speed measurements in both directions, headwind and downwind

RE: Prop question?
 

Thanks for the info der-steurmann, there has been quite a discussion about this.Some club members say they fly faster than the calculated speed all the time.Chris.

RE: Prop question?
 

I'm not convinced that a prop CAN'T fly faster than its calculated speed.

I think its possible, but it may be due to incorrrect pitched props.

I've seen APC 10x7 props go faster than what they should be capable of going.

RE: Prop question?
 

Since a typical prop starts developing forward thrust at a negative 3* pitch I would have to say yes. The calculated forward speed of a 0* pitch prop would be 0 but under the right circumstances it may even get a plane off the ground. This advantage is usually lost to drag as speed increases.