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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-4081919@logan.com>
Subject: Re: [FlyRotary] Re: Scoops
Date: Fri, 15 Jan 2010 07:39:36 +1000
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Thomas,
Nice research.
I found my notes on inclined radiators, they state
1. 0-20/30* will decrease cooling and increase drag.
2. Over 30* things improve.
3. At approx 55* cooling effectiveness is 30% greater than non-inclined rads 
and drag is less by 20%.

If this was followed the height of the duct would be reduced significantly. 
Put that in your drawing and see what it looks like.
George ( down under)


As far as the shape of the diffuser, a classic example is the P-51. The 
problem is getting a true scaled image of the setup.

Attached is a cleaned up version of an actual NA blueprint of the 
scoop/diffuser. I'm in the process of converting the digitized microfiche 
image to a CAD drawing. Even with the files, it's a matter of combining 
multiple drawings to get a true image. The attached does not detail the 
opening of the scoop which is slanted at about 45 degrees. That involves 
plotting from a different drawing to acquire that detail.

As you can see from the drawing the inlet is divided to service both the oil 
cooler and the radiator with separate exhausts. The inlet is only about 7 
inches tall. The radiator consists of a engine cooler (395 sq in) and an 
intercooler (150 sq in). The core itself is 21 inches thick. Pretty massive. 
The slope appears to conform to the 7 degree rule right up to the point 
where it meets the radiator. No big changes in the walls. Very smooth 
transitions. Also, you can see the radiator does sit at a slight angle.

The idea is to draft the setup in AutoCAD and then scale the drawing to fit 
my application and start from there.

There are literally thousands of drawings to sort through but I'm starting 
to make sense of it.

T Mann


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