Sounds like you have the ideal situation with room for that 7 degree
diffuser.  If the inlet is in clean air this setup should work.  I would not
worry too much about oil pan obstructions in the outlet path unless you
simply can't fit your augmenter in the space available.  Theory says that
you must avoid any object on the backside of the rad for 1/2" its width and
this *is* the ideal but we live in the real world, not the ideal.  According
to Kuchemann & Weber study,  lowest cooling drag occures when velocity at
rear of rad is at .1V  where V = Airspeed of aircraft.   (This is only 20
mph @ 200 mpg airspeed.  In practice,  there is not a big penalty for some
obstruction as long as pressure buildup behind rad is < 2" H2O.   If you
meant the "VAM" comment literally, I don't think that is the way to go.
Look at what Charlie Airesman has done for best approach to augmentation.

FWIW,
Tracy


----- Original Message -----
From: "Joseph Berki" <joseph.berki@grc.nasa.gov>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, November 05, 2003 9:30 AM
Subject: [FlyRotary] Cooling


> Hi everyone,
> I decided I did not like the cooling system mounting in the Limo EZ.  The
> scoop is too big and the resulting lower cowl is draggy.  Because this is
a
> pusher I decided to design an inlet that starts half way between the
> firewall and the landing brake location and expands at 7 degrees until it
> reaches the rad and oil cooler.  They will be mounted vertical
> perpendicular to the air flow.  The duct is about 42" in length and is
> grater than 2.5 X the largest dimension of the rad/oilcooler area. I am
> using an exhaust augmenter maybe a version of the VAM pipe.  The problem
is
> that I will have to use a small radiator and maybe the 93 oil cooler out
of
> the car or an aviation cooler with the same volume but thicker.  For the
> rad, evaporator cores like the 81 Caprice vintage (342 cu inches) would
> fit.  I think that this system would work but do not have any experience
> with evaporator cores in pushers.  Another issue is getting sufficient
> clear area behind the rad.  Here is where a dry sump or short oil pan
would
> really help.   Any thoughts on this?  Thanks for any help.
>
> Joe Berki
> Limo EZ
>
>
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