<3975ED06.6AFABF1C@cisco.com>
> I am not convinced that two blades are more efficient than three.
> Especially on the Rotax 912S which has a higher reduction ratio. It may
> be more efficient to have two blades at high speeds but my money is on
> three blades in the takeoff and climb phase. For us in the UK that's a
> major consideration. I'll put my three blades up against two any day of
> the week.
>Jerry
I agree. As I understand it 2 blades will give more theoretical efficiency
but unfortunately also more vibration. When the blades are moving
vertically one has a higher AoA than the other because of the pitch
attitude of the aircraft. With more blades it evens out and is smoother. I
suspect the vibration in the yaw direction might well degrade the laminar
flow a bit, so more drag.
Graham
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