Subject: cooling suggestions?
From: ACRE
Date: 8/3/2003, 8:45 AM


Hi, Paul....I need to address my cooling system at this time. I am
building an SQ2000 canard pusher.  The aircraft in it's
original configuration has two armpit scoops just above the wings for
downdraft cooling, and one large NACA scoop underneath. I
have loads of room on both sides of the engine, and a fair amount of
room under the engine.  If you have the time, might you
look at the following pictures and possibly suggest the best method of
attack regarding cooling?  I can place a large radiator
on each side of the engine, or two evaporative coolers just behind the
armpit scoops, with the oil cooler underneath, or I could
put a radiator under the engine, or ???  Enclosed are pictures with
just the bottom cowling in it's approximate position to show
the available room around and under the engine, as well as two
pictures of the factory cowling (with a Lycosaurus), which shows
the position and sizing of the armpit scoops.  Any suggestions will be
greatly appreciated.  Thanks for taking the time to
assist.  Paul Conner


Not likely to work very well. They are in a a low pressure area and
there is no boundry layer
bleed. Best to go with a P51 scoop and place the rad under the engine.

BTW send that motor mount back to the guy that made it. Very likely your
engine will drop off in a hard landing or high G turn,<<
Paul Lamar

Al Gietzen wrote:


It has been shown on the canards (certainly on the Velocity) that there
is good pressure recovery on the fuselage as you get back to about the
cowling cut line.  Even NACA scoops at that location are effective, so I
would guess that those scoops on your Speed Queen would work well.
Velocitys are cooling IO540s with two NACA scoops at the top of the
going in at the cowling cut.

Al

I talked to a guy at OSH and he differs with that conclusion.
In fact he added arm pit scoops. Here are some pictures.

I want to reiterate on here for the umpteenth time that the inventors
of the NACA scoops do not recommend them for cooling heat exchangers.
The pressure drop through an air cooled engine is far less than
the pressure drop through a heat exchanger. You have been on here for
long while Al, you have seen the scanned in quotes from the original NACA 
papers and I can't understand why you don't accept that.

The IO 540 installation you speak of has two thrust augmentors
and a boundary layer bleeds  for the poorly placed NACA scoops.
The thrust augmentors improve the situation by providing a bit of
suction. I will upload those picture in a moment.

Paul Lamar
 
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