Mailing List flyrotary@lancaironline.net Message #43040
From: Ernest Christley <echristley@nc.rr.com>
Subject: Re: [FlyRotary] Re: combined starter alternator
Date: Wed, 04 Jun 2008 09:41:16 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
George Lendich wrote:


http://ernest.isa-geek.org/Delta/Pictures/EnginePSRUInitialMounting.jpg
http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorFitting.jpg

Ernest,
Certainly Richard seems correct with what he said, but like you say there has been great advances recently. Through this discussion I am getting a better understanding of the problems.
The type of starter alternator I was alluding is the type you have suggested for an alternator i.e short wide type as in the motorbikes.
Is that the core for the winding (in the 2nd photo) Ernest?
If so will it be an alternator (AC) or a generator ( DC) with regulator?
George (down under)
Yes.  That's the stator core.  A local Harley shop guy gave me a damaged unit, which I've stripped down for fitting purposes.  It's a generator, with the inside of the rotor being covered with magnets (that have also been removed).

For this to work as a starter, I'd need it to generate as much power as a typical starter.  During cranking, I believe a typical starter will draw 200A at around 11 volts.  I'm sure someone will correct me if that isn't typical.  That's 2200 watts, or around 3HP.  One way to go would be to adapt one of "hub motors", but the largest of the flat motors that I've seen are rated at only 500W (<1Hp). http://www.powerinmotion.ca/products.php?item=conversion
http://www.goldenmotor.com/

More powerful DC motors can be had, but the conversion would be a bit more difficult.

http://www.greenspeed.us/electric_scooter_e-tek_motor.htm

One of your other desires wouldn't be hard to accomplish.  The Megasquirt engine controller that I'm using will accept any number of toothed wheel for timing input.  It would be a simple matter of mounting a VR sensor next to the flywheels ring gear.  You'd need a second sensor to indicate the position of the #1 rotor, but painting the back of one tooth white and installing an optical sensor would take care of that.

The only thing we need now are time, money, knowledge and skills.


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