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Boy, addressing that question will probably rival the thin/thick discussion
{:>).
I don't think you will find a consensus Andrew. Like most things there are
pros and cons to either/any approach and different platforms drive different
approaches. One reason WW11 aircraft did not have them under the cowl (and
some did) was there simply was not room - given the size of the engine.
But, practical considerations tends to drive placement more than we might
like. You basically have two choices - either in the engine cowl or not.
Some advantages for the tractor installations is that by placing the cores
up front you tends to minimize (but not eliminate) boundary layer ingestion problems, you can have
shorter (if not more efficient) ducting installation, less distance to run
cooling lines, etc.
Someplace on the web there is an URL that has some interesting information and drawings of typical
WWII aircraft liquid cooling installations (unfortunately I have lost track of it). Attached are some of the drawings in that series on cooling. Perhaps someone will have a more recent URL.
The canard folks will have to address why they put them where.
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda/index.html
----- Original Message ----- From: "Andrew Martin" <andrew@martinag.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, November 15, 2007 7:55 PM
Subject: [FlyRotary] heat exchanger placement
Hi
Following on from this thin vs thick radiator discussion. What's the
general consensus on placement of the heat exchanger/s? Seems to me the
most efficient WW11 planes had the exchangers mounted under the wing or
fuselage but nearly everyone here is placing them under the cowl, is the
reason for this just because its an easier installation to make, or is
it no less efficient at our power/speed.
My aim is to minimize total drag even if it means a longer build time to
get the installation correct, current thoughts are to place a short
thick coolant exchanger under the fuselage and have a clean tight
fitting cowl with only inlets for induction and oil heat exchanger,
hopefully there will be enough air going through the oil exchanger to
keep under cowl temps reasonable.
Am I just plane crazy?
Regards Andrew Martin.
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