To: baranfin
"I would think that the retreating blade only stalls on the very edges and then quickly recovers from the stall as it moves towards the 6 oclock position. So that would mean that it would dip down momentarily at the 9 oclock position. this would then move the rear of the disk downward and result in the front climbing. The roll would just be caused by the increased drag on the left side of the system right"?
Response:
The action you describe may be correct but not sufficient to cause a “full stall” When the tips are in the stall region they may do what you stated but not to the extent you stated and this may account for the vibration experienced at the onset of retreating blade stall however in a full stall as much or possibly more than 30% of the blade span is involved and at this time there is sufficient lift differential to cause the flapback / blowback.
[ 05 December 2001: Message edited by: Lu Zuckerman ]