P-51 style should look pretty cool with a bent canard...And no I don't
have any drawings, hell all I got is a wing.
tc
Well Todd, we have the bend canard too :) now all I have to figure out
is..what the heck is a P-51 type scoop with boundary layer air bleed? Does
anyone have some good pictures, formulas, data etc for configuring these
things?
...Chrissi
Surely you have seen pictures of a P51 Chrissi?
Don't copy the duct however. It is wrong! You will need an opening
at least 20% of the rad area and a very large opening at
the rear of the airplane to let the air out. Twice the inlet area
at least.
I would guess the boundary layer to be at least an inch
thick at the back of a canard. What say you Al Gietzen?
About 1.5" thick 10 ft back from the nose at 160 kts.
Big outlet area causes drag. You'd like to have the air exit at a velocity
close to the speed that it came in. Typically figure for the expansion due
to heating plus a little margin gives you 1.6 to 1.8 times inlet. Make sure
the exits are in low pressure areas; like at the back of the cowling in a
pusher.
BTW, on the Velocity, the pressure recovery near the back of the airplane -
say about the firewall - is quite high; making attempts at having air come
out the side of the cowling ineffective. NACA scoops have been shown to be
effective inlets at the engine, but likely would not have the pressure of a
ram scoop.
Al
Adjustable cowl flaps are called for as the dynamic pressure is four
time higher at 200 MPH than it is at 100 MPH. 100 MPH is the critical
design point as that is closer to the speed people takeoff and climb out at.
An air cooled engine I suspect has a lower pressure loss across it than a rad
and that is why NACA said NACA scoops are not suitable for rads and
oil coolers. I just down loaded that pertinent 12 meg PDF file from:
http://naca.larc.nasa.gov/reports/1945/naca-acr-5i20/
Paul Lamar
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