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Old 15th Jul 2009, 00:39
  #475 (permalink)  
IFMU
 
Join Date: Mar 2005
Location: Poplar Grove, IL, USA
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Originally Posted by slgrossman
It seems to me, at least intuitively, that having the propeller thrust behind the CG would actually be a destabilizing factor in yaw (and perhaps pitch as well).
-Stan-
I thought in the fixed wing world that tractor propellers were considered destabilizing and pushers stabilizing. If I remember correctly there were issues with pitch stability on the old Northrup flying wings when they transitioned from pusher propellers to jets.

If you consider the thrust vector to be normal to the pusher propeller disk, I think it would be stabilizing. Consider a disturbance which pushes the nose up so the airplane is at a positive angle of attack. Then break the vector into a thrust which is orientated in the direction of travel, the left over vector (for a pusher) will try to push the tail up, reducing the angle of attack.

-- IFMU
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