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
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