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From: "Bryan Winberry" <bryanwinberry@bellsouth.net>
To: "'Rotary motors in aircraft'" <flyrotary@lancaironline.net>
References: <list-4152736@logan.com>
Subject: RE: [FlyRotary] Re: The stalled propeller blade
Date: Thu, 4 Mar 2010 21:34:30 -0500
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Dave,
Please don't attribute that statement to Lynn.  He was responding to me with
the same font.

And you are correct about the pitch of the plane changing the AOA of the
prop.  I seem to recall this being talked about in ground school many years
ago.  But still, fixed prop AOA isn't something we intentionally control
like a CS prop.   At least that's the way it seems to me. P-factor is just
something we have to put up with till we gain higher speeds on climbout.

I need to go to the basement and work on the project or I'll never get to
the prop part.

Thanks,
Bryan

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Dave
Sent: Thursday, March 04, 2010 8:01 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: The stalled propeller blade

Lynn Hanover wrote:
>
>  AOA, I think in terms of the wing producing max lift.  The AOA 
> changes with elevator input.  A prop is not unlike a wing, but I still 
> don't have a grasp of what is causing AOA change in a fixed pitch 
> prop.  But, usually I have to read things three or four times in order 
> to "get it".
>
Ok.. a "fixed" pitch prop can have a changing AOA.. heres how..

The pitch angle of the plane.. itself... along the crankshaft axis.. has 
an impact on how the prop sees the oncoming air, and hence varies the 
angle of attack of the prop blades.

An airplane flying at lower airspeeds in its regime will tend to fly 
nose high..

An airplane flying at higher airspeeds will tend to be nose level or 
even a tad nose down..

The same prop on the same plane at two different speeds will result in 
two different pitch angles and therefore two different angle of 
attacks.. which then have an effect on thrust.

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