Ernesto Sanchez wrote:

Paul have you ever talked with Klaus about P-51 scoops??  He once suggested
in an article that a modified NACA scoop with straight sides (It would look
like a ramp) would provide the needed cooling with less drag than a scoop
hanging in the airstream.
Ernesto

----- Original Message -----
From: "Paul" <rotaryeng@earthlink.net>
Sent: Tuesday, August 22, 2000 1:30 AM
Subject: wing root rads

Doug wrote:

>From the last sentence...

Also, don't ingest the boundary layer if you plan on significant
recovery of dynamic pressure.

Is that the reason that the P51 and powersport RV have their scoop

dropped

down from the fuselage? It always looked like that air would boil around
above the top lip.
Doug

Yes. The idea with a fairly narrow scoop like the P51 is the air is

diverted

to the sides above the intake. The wider the scoop the more difficult it
is to do this and still keep the drag low. The ideal scoop shape is a
a round hole. Maximum intake area for minimum internal and external
surface area that causes air friction.

Paul Lamar

Ernesto Sanchez wrote:

Paul have you ever talked with Klaus about P-51 scoops??  He once suggested
in an article that a modified NACA scoop with straight sides (It would look
like a ramp) would provide the needed cooling with less drag than a scoop
hanging in the airstream.
Ernesto

Yes. Lots. I see him almost everyday as his hangar is across from mine.
Agreed. Surprising the NACA duct is way aft on the fuselage of a Variez.
Charley Aireseman's airplane is also cooling well with a tiny NACA and an 
exhaust augmentor.

Here is a pictures of Charley's NACA. As a guess it is about eight inches 
wide.

Paul Lamar
 
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