Herb Sanders wrote:

Here is a real world example of scoop design. We bought a Long EZ that had the oil
cooler mounted behind the main spar in a box fed by a scoop constructed by cutting
the cowl back, pulling it down and glassing the sides, and leaving a 2" x 4" scoop at
the cowl surface feeding into the box.  It did not cool well. It would go to red line
in flight at wide open throttle and have to be step climbed - still ran at near
redline, even at reduced throttle.

We took a scoop available from Velocity that hangs down from the surface about 1",
has a nice teardrop shape, and about 3" dia round opening (7 sq in compared to 8 sq
in on the scoop we were replacing). It came with sharp edges, but I took a 5/16 dia
nylon tube, split it length ways, filled it with 5 min epoxy, and forced it on to the
lip. After cure, we filled in behind the tubing with micro inside and outside, and
faired it into the sides. Now, in 100 deg Memphis weather and at gross wt, we can
climb WOT to 10,500' and not see oil temp over 195 deg F.

>From what I have read, a perfect NACA flush inlet is about 85% efficient compared to
a free air ram inlet at pressure recovery. On my Velocity project, I have built a
plenum over the top of engine fed by a 9" x 3" free air ram scoop 1" above the fus
top. My plan is to feed combustion air, oil cooler air, and engine cooling air all
from the plenum chamber. Any redneck who likes the look of aCamaro with a hood scoop
would love it. Herb Sanders

 
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