PPRuNe Forums - View Single Post - Rotation side of jet engine? / critical engine?
Old 8th November 2012 | 15:28
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Daniel_11000
 
Joined: Oct 2007
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From: ITALY
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thank you for clarification, but..
the effect you are referring to is sometime called P-Factor (I do not know why), and is purely, as correctly you are saying, an aerodynamic effect ; when the propeller axis is not parallel with the wind (but only and strictly in this case) , the downgoing blade has an higher AoA of the upgoing blade, and this creates an asymmetry, which results in moving the center of lift (thrust, in the propeller case) toward the downgoing blade – and not in the center of the propellerazis. This happens an a bycicle a/c, even if it rests in its three-point attitude ; even if the axis is not moved, the asymmetry gives a yawing torque.
But when the tail is lifted in ‘my’ Cub (or in the Harrier !), the rotor axis (propeller, or jet engine spool in the Harrier case) is subject to a disturbing torque, and reacts with a 90° torque, which becomes greater if the disturbing action is quicker (gyroscopic effect)
D
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