Paul wrote:

Hi all...here is the latest success story for my 13b powered

SQ2000

canard.  I removed the ram air scoop from the top cowling.  I

then

installed a NACA duct with a 3 inch hose outlet in the lower
cowling in the wing root area.  I made an aluminum plenum with

a 3 inch

hose outlet to attach to the new NACA duct.  Now, the incoming

air goes

directly to the throttlebody and no longer pressurizes
the low pressure area of the cowling. Climbout water temps

dropped from

the previous 205 (with the ram air scoop) to 180.  I think if I

seal the

plenum as Paul Lamar suggested, I can further
decrease my temps.  It was 81 degrees outside, and the water

temps

climbed to 180 during the climb.  Settled down to 170 downwind.

I think

I'm on the right track....will try sealing the plenum
next. Oil temps maxed out at 180, and dropped to 160 downwind.

Not as

low as I would like them to be, but going in the right

direction.  Here

are a couple pics of the NACA scoop and the intake
plenum. Paul Conner

You will get more power with a ram air scoop instead of the

NACA.

What is current intake manifold pressure?

Paul Lamar

I have to look at it during flight. My MAP fluctuates between 15

and 20 at

idle, and if I recall correctly, at WOT it was around 5.  That is

the only

indicator I have. There is a small rubber hose attached to the

intake

manifold that goes directly to the MicroTech ECU. The screen on

the handheld

programmer (that is actually hard mounted to the instrument panel

instead of

being handheld) shows the MAP to be around 15 to 20 at idle, and

decreases

with rpm's, up to around 5" MAP.  That was with the ram air scoop.

I failed

to observe the MAP readings with the new intake plenum and the new

NACA

scoop.  Static rpm's were excellent, however.  I will take note of

the MAP

during flight on the next flight.  It was a short flight (a couple

of

circuits around the pattern) as I wanted to get back on the ground

to make

sure nothing was coming loose, etc.  Pulled the top cowling and

everything

is still in the same place. I like it when things stay put.
     I like the idea you came up with (the red rectangular fix to

seal the

NACA inlet to the radiator).  I was considering silicone or

silicone rubber

engine baffle material, but I prefer just sealing it as you

suggested. All

it will take is a small piece of aluminum which I can secure to

the sides of

the plenum with blind nuts and L shaped aluminum angle, and a

little

silicone in the joints. That way, when I remove the lower cowling,

it will

have no effect on the integrity of the radiator/plenum seal.

Thanks.  Paul

Conner

That that should help but the ultimate is get rid of the NACA duct,
use a P51
type scoop, Kays & London wedge diffuser and mount a thinner rad
under the
engine like Perry Mick is doing.

Paul Lamar

Paul(L) -
I know you don't like NACA scoops for cooling - but with Paul's
(Conner) current temps (~180f) don't you think the P-51 scoop is going
to add more drag - and potentially not improve temps all that much?

I think Paul Conner has a winner just like it is.  He might even be
able to tweak it a bit and get another 5-10 degrees off by radiusing
the aft end of the NACA and putting a capture plate in the bottom.
But I don't think he needs to do any extreme surgery. Let's
congratulate him on a great success!

Joe Hull
Bellevue (Seattle), Washington
Cozy MkIV #991 (still working on Engine & Electrical & Finishing)
http://www.maddyhome.com/canardpages/pages/JoeHull/index.html

True P-51 scoops add frontal area and consequently drag.
It is not just me. It is the inventors of the NACA duct that don't like them
for heat exchangers :)

So far Paul Conner has been flying in cool weather. That makes a big diff.
The temp difference  is 80 F to 180 F. 100F. For every one degree F loss in 
temperature difference there is a loss of 1% in cooling capacity roughly. Ruff rule of
thumb. Wait until summer when the ambient gets to 110 F. Also climbing out 
to pattern altitude is not hard. Try climbing over a mountain or cloud in summer
for a half hour.

My favorite for pushers would be this 3D. Real easy to implement. I suspect 
less drag than a P51 type scoop.

Nobody is not congratulating him. He has been on here for years but went
ahead anyway against conventional wisdom and he is now asking for help.

Paul Lamar
 
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