Mailing List flyrotary@lancaironline.net Message #17985
From: William <wschertz@ispwest.com>
Subject: Re: [FlyRotary] Re: E-shaft permanent magnet alternator
Date: Fri, 25 Feb 2005 21:34:29 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Good point about the belt taking out your controls. I know Todd has been successful so far, and I wish him continued good fortune. Myself, I would like the PM type alternator to act as a supplement to a regular alternator to give me longer to run with the all electric airplane.
 
If you have an EWP, I believe that you *must* have a second source of current. Add up the loads, Mark S reads 17 amps for the ignition and fuel pumps, the EWP is 3-5? and if you run any other equipment you are easily over 20 amps. A 17 AHr battery will give you 17 A-hr only at the ~20 hr rate, i.e. at about 1 amp draw. At 20 amp draw, the life will be considerably shorter.
 
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From: Paul
Sent: Friday, February 25, 2005 9:03 PM
Subject: [FlyRotary] Re: E-shaft permanent magnet alternator

I was not trying to imply that an EWP is more reliable than a belt. I said that I really like that idea. Our canard pushers have the control systems running along the firewall, where a broken belt can take them out in an instant.  I don't like that.  An engine without belts...I like that.
     I don't know if an EWP is more reliable than a belt. I do know, however that it is better designed for a cooling system than a belt driven waterpump. A belt driven water pump slows down at idle, where there is typically less airflow through the radiator. Right when you need the most flow, the belt driven water pump goes on vacation. The EWP on the other hand, senses the rise in coolant temperature, and increases flow even at an idle. The belt driven water pump cannot do that.  Conversely, while at cruise and you have more air cooling the radiator, it is then that the belt driven water pump really kicks in, due to the engine's higher rpm's.  The EWP is smarter than that. It realizes that you are not at wide open throttle, and at cruise, and slows down the flow. Paul Conner
 
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