PPRuNe Forums - View Single Post - What causes "blowback/flapback" when accelerating through transverse flow effect?
Old 14th Aug 2022, 18:29
  #51 (permalink)  
HissingSyd
 
Join Date: May 2016
Location: Exeter
Posts: 45
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by ShyTorque
So called “rigid” rotors still work by flying the rotor blades to their required positions, rather than by gyroscopic precession.

The “rigid” description is in that there are no specific hinges on the head, ie there are no leading/lagging, flapping or pitch change hinges. The blade support system is all one piece, which can twist/bend to allow relative blade movement and pitch changes. The Lynx type of head was/is semi rigid in that it does have conventional pitch change hinges.
It might be worth emphasising that all the forces that the rotor exerts on the helicopter are transferred through those hinges/supports. For a fully-articulated rotor head that force is just the blade tension [1]. All that aerodynamic forces on the blades are doing is altering the angle at the hinge. I suspect this is largely true for rigid types.

[1] For those interested, this is discussed on p13-14 of that Sikorski manual.
HissingSyd is offline