Mailing List flyrotary@lancaironline.net Message #2591
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] EWP seized
Date: Mon, 18 Aug 2003 08:52:15 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
I do find that the motor gets too hot to hold your hand on continuously, but it has been like that since I first used it. While I don't really like this motor high temp, I realize it is not uncommon for small motors so I wasn't too concerned. Now I wonder if it was a factor, combined with under cowl temps from my run-up.
    
Sorry to hear about that.  Sounds like it wouldn't hurt to add a small blast cooling tube for the EWP motor.  No point in torturing the little motor that you're trusting your life to :-)
 
That being said, I would suspect that you have a bad bearing, which would explain the odd noise you heard before, and the recent lockup.  Certainly, you're not subjecting it to any more heat or stress than it could get in a car, so I'd have to assume that you just got a unit that was defective.  I'm not sure if they'll honor the warranty, but if it were me, I would buy another unit, rather than fly with the one you have.  
 
Here's another thought.  Did you confirm that it really didn't blow the fuse when you replace it?  If the pump was seized, and you put power to the motor, it should have blown the fuse.  If it didn't, that would suggest an internal thermal protection device in the motor, and I'd be mighty interested to know what temp that thing trips at.  Since the fuse blew initially, we can assume that the thermal protection had not kicked in prior to blowing the fuse.  In other words, heat from the electrical load of the struggling motor did not trip the thermal protection.  Next, the motor was heated further by the engine compartment, and 240 degree coolant.  Did the thermal cutout occur due to the high operating temps?  If that's the case, it would be disturbing, since high temps could result from a number of other problems, and the last thing you need is your water pump to quit at the same time.  Keep in mind that this whole paragraph is pure speculation, but is certainly something to think about.  
 
Good luck,
Rusty
 
 
 
 
 
 
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