Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml@lancaironline.net
Date: Fri, 06 Aug 2004 13:19:11 -0400
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From: "DJ Molny" <djmolny@yahoo.com>
Subject: RE: [LML] Prop pitch with pressure loss
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In-Reply-To: <list-354798@logan.com>

Aerobatic planes are subject to significant fluctuations in oil pressure
during maneuvers, so their props default to coarse pitch to avoid
overspeeding the engine.  This behavior is purely a function of the prop
design, and is used on both Lycoming and Vedeneyev M-14 engines.

More info at: http://www.russianaeros.com/propellers.htm

Regards,
DJ Molny
Extra 300/L
Rocky Mountain Aerobatic Club


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Barry
Hancock
Sent: Friday, August 06, 2004 10:31
To: Lancair Mailing List
Subject: [LML] Prop pitch with pressure loss


On Aug 6, 2004, at 9:15 AM, Richard Kaplan wrote:

> On the other hand, with low oil pressure it may not be
> possible to adjust the prop and/or the prop may go
> into the default high RPM/low pitch configuation with
> a prop governor malfunction.

I have often contemplated the wisdom of this configuration.  I fly 
Russian warbird aircraft with M14P radials on them as well, and the 
failure mode is high pitch....seems to make a LOT more sense to me.  
Can someone enlighten me on why (from a philosophical standpoint) the 
engines that spin the other way (i.e. American) throw then prop to high 
drag upon pressure loss?

Thanks in advance!

Barry
N122LL


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