Dan Ruggirello wrote:

Paul,
What are all the variables shown in the graph area of figure 5 of

the Me109?

Dan

Its from page 9-5 in Hoerner's book Fluid Dynamic Drag.

Efficiency is on the left y axis.  A formula is give for the

efficiency

to define it I think. The funny looking vertical squiggle line is
called the pressure loss coef. In this example the curve is plotted

using

a pressure loss coef. of 3.2 I suspect. The measured data is plotted

around

that curve.   w/V is the ratio of input velocity
in the duct at the face of the core (w) over the forward velocity of

the

aircraft (V) and is the x axis.

c is the cord of the wing.

S is area. So S sub block / S sub i is the rad area over the inlet
area I think. Inverted over the way K&M defines it.
It is 6 so that is about 16% I think.

Here too is another interesting Hoerner graph on this subject.

To really get a handle on what he is talking about you will have
to read the whole book. Or at least chapter 9.  He kind of builds
up on everything right from the start of the book. I get the

impression,

from my limited knowledge of aerodynamic theory, that he generates

his

own nomenclature. Each book I have on this subject
uses different nomenclature. Kays and London call diffusers
"headers". A major head ache when trying to decipher this stuff :)

If there were two of me one of us could scan it in and convert that
chapter (Chapter IX - Drag Due to Internal Flow Systems) to a pdf

file.

Peter G might be able to enlighten us on this subject. I am sure

Peter

has the book.

Paul Lamar

Don  Dunbar Wrote. Hi Paul and Dan. Dan would you be so kind to run my
duct  and  radiator installation through your analysis program for me.
What information would you prefer Auto-cad, dwg, dxf would suite.

--
Best regards,
 ddunbar                            mailto:ddunbar@echidna.id.au

Yes. We will need the dwg's Don. ACAD will work. I will convert them to
gifs.

Paul Lamar

-Dan Ruggirello wrote:

The file formats most easily imported are IGES v.5.1 and DXF acad2000.  A
gif/jpg will work too, just a bit more time to reconstruct.

Paul,
Thanks for scanning in those pages.  For a minute there I thought your cells
divided into two to scan the whole chapter ;-)  The local libraries don't
have the Hoerner book - I may see if I can find a used copy.

Dan- 

Be prepared for sticker shock :)

Paul Lamar
 
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