Mailing List flyrotary@lancaironline.net Message #3583
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Evans NPG+ cooling systems
Date: Tue, 7 Oct 2003 10:35:18 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message

Its tough to beat pure water for removing heat.  But, this NPG+ stuff might be worthwhile considering - who's going first??  My 0.02 worth.

Ed Anderson

 
Ed, you sure saved me a lot of typing :-)
 
I've looked into the Evan's stuff before, because it gets mentioned on the RX-7 forums a bit.  It's a known fact that it doesn't cool as well as water, or even 50/50 water antifreeze.  Their main claim is that you can get better fuel efficiency at higher temps, however, higher temps are not good for our engines, and they aren't good for power either.  Here's a quote from Lynn that was in a previous message:
 
The engine builder reports power lost above 160 degrees on the oil temp. Water under 200 is OK. Power loss above 180, but no damage.
 
Remember the rule, when Lynn speaks, I take notes :-) 
 
The main thing that I find interesting about the Evan's coolant is that you can run a no-pressure system.  That would certainly eliminate some leak potential.  Also, I wonder if it wouldn't extend your engines life a bit in the event of a leak, slipping belt on the water pump, etc.  I can't see it saving the engine, but it might give you more chance to make an airport landing.  
 
If I end up with too much cooling capacity in the final cowl version, I'll think about trying the Evan's stuff.
Rusty
 


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