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Date: Sun, 04 Jan 2009 15:26:54 -0600
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Conical mount
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George Lendich wrote:
> Can anyone give a brief explanation of the conical engine mount, and 
> why it's built the way that it is. Not that I intend building one, 
> just curious as to why the mount points are turned inwardly and appear 
> to be focused at some point - is this a theoretical focus point that 
> has the CG of the engine at it's focus?
> George (down under)

That's the dynafocal mount. You've got the right idea about the reason. 
There are at least 2 versions; the 2nd type is for some engines used on 
twins that have extended hub props (cg is farther forward, and the 
converge point of the bolts is also).

The conical mount has all 4 bolts parallel.

Charlie