PPRuNe Forums - View Single Post - Dissymmetry of lift, flapping and blowback...
Old 22nd November 2003 | 00:06
  #2 (permalink)  
Lu Zuckerman

Iconoclast
 
Joined: Sep 2000
Posts: 2,132
Likes: 0
From: The home of Dudley Dooright-Where the lead dog is the only one that gets a change of scenery.
Thumbs up Which way is up and other questions

To: Golden Rivet

I may be totally wrong and risk the wrath of NickLappos and Shawn Coyle but this is what I think is happening. The upward flapping of the advancing blade and the downward flapping of the retreating blade occurs during translational lift flight or up to approximately 20 knots. This will result in a roll to the right. The pilot can remedy this situation with cyclic input. If there is a tendency for blowback the pilot can introduce forward cyclic. The lift differential (Dissymmetry of lift) is countered by pitch flap coupling. When the advancing blade flaps up due to the increase of lift the pitch flap coupling will extract pitch from the blade reducing its’ lift. Conversely if the retreating blade flaps down pitch is increased due to pitch flap coupling thus equalizing the lift.

In addressing this situation you must deal with the individual blades and not the disc.

Duck for incomming.

Lu Zuckerman is offline  
Reply