Mailing List flyrotary@lancaironline.net Message #30540
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Heaters
Date: Mon, 6 Mar 2006 13:09:38 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Yeah, Joe.   I have an oil cooler core sitting on my side of the firewall that extracts heat from the coolant system.   However, the small amount of heat its capable of extracting is so small compared to the thousands of BTU of heat you need to get rid of each minute from a flying rotary that the effect on cooling is nil. 
 
  I know folks have turned on their heaters to save an over heated auto engine - but, those engines were  not being operated at high power settings if they were having cooling problems. 
 
 In fact, if you were able to come up with something that extracts significant amounts of heat - it would quickly broil the occupants of the cockpit {:>).
 
Not trying to discourage you, Joe,  but I do believe that for it to be worth the weight and complexity that it would have to extract at least 10-15% of the coolant waste heat.  If you are pulling 160 HP you need to dump approx 5000 BTU/min through the cooling system.  So 15% of 5000 = 750 BUT/min.  Now if my Units converter is correct that about to 13.17647 Kilowatts.   I think that would get a cockpit a mite  warm in a hurry.
 
  Even if you are cruising at a more realistic 110 HP and only taking 10% of the coolant heat load then that would be 10% of 3362 BTU/min = 336 BTU/Min = 5 Kilowatts so that would be like having 5 hair dryers on full hot blowing air into the cockpit.  Again, might get a bit warm.  Now of course, you could have a valve to control the flow of hot coolant and maintain a more reasonable cockpit temperature - but then there would not be much engine cooling benefit. At least that is the way it appears to me based on what I understood from your description.
 
Just my $0.02
 
 
 
Ed
----- Original Message -----
From: Joe Berki
Sent: Monday, March 06, 2006 12:23 PM
Subject: [FlyRotary] Heaters

Has anyone designed a separate system that extracts heat from the engine compartment or components to heat a fluid in a separate system using a heat exchanger to dump the heat into the cabin and a separate pump?  This way you are not making this system part of the engine cooling system and can run lower pressure and be able to shut it off without affecting the engine system.  I was thinking of a device that subarus had sandwitched between the oil filter and the block.  Any thoughts?
 
Joe Berki
Limo EZ 
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