PPRuNe Forums - View Single Post - Video - Flapping to Equality / Dissymmetry of Lift
Old 25th Jun 2019, 02:02
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Ascend Charlie
 
Join Date: Sep 2002
Location: Great South East, tired and retired
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Sorry, Mitchaa, but it ain't "Flapping To Equality". It is "Blades flapping as dictated by the swash plate."

FTE will only happen when the cyclic is neutral and a puff of breeze causes a differential in relative airflow between advancing and retreating blades. The advancing blade will flap up, and the retreating blade flaps down, the opposite of what is shown on this video. This FTE makes the disc tilt backwards, and the helicopter would then move backwards - but then the relative airflows are then reversed, the disc flaps the other way, and you are into the realm of dynamic instability.

BUT! The pilot sees that the disc is flapping back right from the start, when he wants to go forward, so he uses cyclic to make that happen. End of FtE. The aircraft does what the cyclic tells it to do. Advancing blade goes down instead of up, disc tilts forward, total rotor thrust points forward, and away he goes.

Nice video, though, and the pair of balls flapping away is doing its job of absorbing vibes.
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