You definitely need more outlet than inlet to keep the air moving
through. You've got the right idea - maybe 6" opening at rear, and
definitely ending a couple of inches or more behind the firewall.
Don't forget to round the bottom firewall lip with alum. too !
If you make it out to the meeting this Sunday, you can have a look at
mine - it's working great now. I have a manual cowl flap at the bottom
that should handle summer temps. easily - not too hard to add, and it'll
save a bit of cutting & bending later ! ;-) :-)
.......bobp
-------------------------------orig.-------------------------
On Tuesday 11 January 2005 02:02 am, british thunder wrote:
I'm currently building a 4 door cowl for my Rebel. I have the MC-3B nose
bowl, have completed the top and 2 sides the top doors are already in
template form.
I'm having trouble with the lower, due to where my exhaust is for mounting
the hinge.
The question: Is there a formula to figure out the size of the opening to
allow the right amount of air out.
The only thing I have found is on a Mustang II, he used the outlet was 75%
of the inlet.
Does this sound right????
The openings on the MC=3B total aprox 110 square inches. Thinking I'll have
to leave the bottom hanging down 4-5 inches. with 1-2 inches past the
firewall and a 20deg. lip down.
Previously I had the "speed "cowl. The ch. temp was ok 375-400 but the oil
temp was 220-240 in normal flight this is in 22-24 deg. weather, not sure
what it will be like in warmer weather or on long flights, the longest so
far is 2 hours.
Thanks for the help
Cecil 014r
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