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Date: Wed, 06 Oct 2010 11:35:17 -0400
From: Ernest Christley <echristley@att.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Permanent Magnet Alternators
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Ed Anderson wrote:

> 1.  Mechanical reliability under the stress (hot engine compartments, 
> hours of high rpm running)
> 2.  Cooling mechanism - I don't see any cooling fans like an auto alternator
>  
> But must admit 22 oz and 2.5 inches in diameter would sure make them 
> attractive for aircraft use if my concerns are invalid
>  

I doubt it would take any sort of sideload for any reasonable amount of time.  That would require much beefier bearings 
than what I can imagine these motors having.  It would need a center drive, or some other mechanism to isolate the side 
loads.  Driving it off of the oil metering pump drive or the ignition drive could be a possibility, except for:
1) the stock worm gears would have to be replaced with something more substantial
2) at 2000, the RPM is unlikely to be enough to develop 16V if Lynn is able to run it up to nearly 8000 with 11.7V.

These motors are wide open (and the ones that aren't have radial cooling fins).  I wouldn't worry about the cooling as 
long as it is in any sort of airflow at all.  There are no solid state parts to overheat.  The only thing that could be 
affected by heat is the insulation on the windings, or the magnets if you heat them past their Curie temperature.  I 
don't think either would be a concern if the generator was just used as an emergency backup to drive an ignition.