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How does a helicopter rotor keep spinning in the same direction when autorotating without reversing the pitch

From your answers, it seems to be the upward air hitting the upward sloping mid to rear underside of the blades as in the diagram below that keeps it spinning the same way with forward pitch and ...
Peter R. McMahon's user avatar
4 votes

How does a helicopter rotor keep spinning in the same direction when autorotating without reversing the pitch

For ease of exposition, let's consider a helicopter simply hovering. The typical airfoil along the blade sees a velocity $V$ which is the sum of two components: an horizontal component $U$ due to ...
sophit's user avatar
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5 votes

How does a helicopter rotor keep spinning in the same direction when autorotating without reversing the pitch

John K's explanation is correct. However, It may be interesting to add some text and an illustration taken from a classic book, 'The Autogyro and how to fly it' By Reginald Brie (1935):
xxavier's user avatar
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11 votes

How does a helicopter rotor keep spinning in the same direction when autorotating without reversing the pitch

Most rotors can go near zero pitch or slightly negative with the collective all the way down. But the blades don't have to go to negative pitch to get driven forward by the airflow coming up through ...
John K's user avatar
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2 votes

Is blade flapping "fully automatic"?

Blade flapping is both due to an "automatic" effect and a "controllable" effect. The "automatic" effect is exactly as you've understood it. The advancing blade sees a ...
sophit's user avatar
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1 vote
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Is blade flapping "fully automatic"?

Blade flapping is indeed automatic but note that the cyclic control of the pilot will fine-tune it such that lift is equal on both sides of the rotor disk. It is not the maximum upward travel of the ...
Peter Kämpf's user avatar

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