Received-SPF: none
 receiver=logan.com; client-ip=207.189.223.49; envelope-from=billdube@killacycle.com
Message-Id: <4.3.1.0.20051211230518.01f566d8@mail.chisp.net>
Date: Sun, 11 Dec 2005 23:19:26 -0700
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
From: "BillDube@killacycle.com" <billdube@killacycle.com>
Subject: Re: [FlyRotary] Re: "P" factor?  Re: Static Engine RPM
In-Reply-To: <list-871997@logan.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; format=flowed

	P factor is caused by the angle of attack of the prop blades relative to 
the motion of the prop through the air. No P factor when the plane is not 
moving. Lots of P factor at high power low speed.

	Tricycle gear airplanes do indeed experience P factor. Go over a high 
mountain pass at the service ceiling and you will experience P factor in 
spades. After a day of mountain flying, I get cramps in my right leg from 
pushing the rudder pedal.

	If the propeller is tilted upward relative to the oncoming air, as the 
blades travel downward, they have a large angle of attack. As they travel 
upward on the other side, they have a small angle of attack. They pull hard 
on the down stroke, and much less on the up stroke. The "swirling" you may 
observe is the result of a lot more air being pushed though one side of the 
prop circle compared to the other.

	Cocking the thrustline slightly helps reduce the rudder pressure at slow 
airspeeds.

	Bill D.

	Perhaps you all know this already, but it didn't seem like everyone had it 
100% correct from what I read in some of the previous posts.