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

Here are some pictures of the IO540 installation. The purposes
of the dams around the NACA scoop are to divert the low energy
boundary layer air. Given the position of the NACA scoops on a 
backward slope of the fuselage it is remarkable that they work
at all. The dual thrust augmentors must be working sucking the air out
very well indeed. This air cooled aircraft engine installation is 
extremely well done in engineering, cosmetics and execution.


Paul Lamar
 
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