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From: "jesse farr" <jesse@jessfarr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-902760@logan.com>
Subject: Re: [FlyRotary] Alternate alternators
Date: Tue, 27 Dec 2005 13:36:27 -0500
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The simplest, surest, country boy way I know is to make one, put it on the 
old test bed and drive it around. Lot less theoretical engineering work and 
if/when it brakes, you just drive it home. Believe me, you don't fall too 
far that way and you can mistreat it much more than you ever should more 
than a foot or so off the ground. <g>
jofarr, soddy tn

----- Original Message ----- 
From: "Ernest Christley" <echristley@nc.rr.com>

> One of the things Richard and I discussed yesterday was going with the 
> RX-8 style of pickup and using the distributor shaft to drive an alternate 
> power source.  He rightly noted that the gears probably aren't rated to be 
> very strongs, since all they do is drive the distributor and oil pumps. 
> The questions are 1)How much load would a generator add?  and 2) How much 
> load can the gears take?
>
> I don't have anything for the second question, but I got some numbers for 
> the first part using: 
> http://www.aeroelectric.com/articles/alternators/UA/Alternators_3.html
>
> Assuming a 20A load at an 800RPM idle as the highest torque a 65% 
> efficient generator would be applying:
>
> (14V x 20A)/.65 = 431W needed to drive the generator.  431/746 yields 
> .577HP.
>
> (.577HP x 63.024) / 400RPM = .091 in-lb of torque on the gear.