With respect to the tip-path plane...

The cyclic control system of the Bell-47 helicopter does not use feathering bearings; cyclic pitch is applied to a pair of pivots of the universal joint suspension system via linkage from the swash plate. The B-47’s feathering bearings are used only for collective pitch.
Bell-47.jpg
 
Hello all...

This morning, I finally understood it; I mean, I finally saw the equivalence of flapping and feathering in our gyro rotors as an exclusively mechanical effect... This animation was very helpful:

https://en.wikipedia.org/wiki/Univer...rsal_joint.gif

Seen from the right-hand axle, (say, the 'tip path axis') the blades don't flap; they just feather... And the amplitude of their angular feathering motion (the 'flapping angle') is the same as the angle between the two half-axes of the Cardan joint (the 'blowback angle')...
 
C. Beaty;n1143481 said:
Like this?

Exactly... I was thinking in the 'teetering' rotor, but it's the same thing...
 
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