Back to square 1!!
We had a similar thread back in
April!
ROT's about exit/intake ratio where exit HAS
to be bigger are gospel. If you want to reduce cooling drag, read up on the
following:
(I am cheap enough to just copy my past
posts and replies here:))
Not sure I follow you about exit larger than inlet being
gospel. IF you mean subject to translation errors and the cumulative alterations
of many scribes I might see your point. Everybody going fast has smaller exits
than inlets.
As I stated that is because the inlet must be sized for
WOT climb where you are moving a lot of air. At that point the outlet must be
larger as well like 150% to draw the air through and allow for expansion. OR you
must use an exhaust augmenter-take your pick.
As the speed increases and the power level drops in cruise
you need to close the outlet down (unless you want a large drag penalty).
Ideally you should close the inlet down as well. Since it really doesn't matter
much on a Tractor (because of external diffusion and an ugly front end
aerodynamically anyway) and variable inlets are more complicated it does not
typically make sense to fool with closing the inlet down.
So ideally you should have an inlet sized to cool the
thing in climb, followed by an exit that is variable from around 150%-70% or so
depending on how you plane to operate the aircraft.
You want the minimum air flowing through the cooling
system at any cruise operating point to create the least drag. Unless you are in
full power climb, and then you just want to cool the thing.
A single size for your outlet is a point design and will
create excess drag or inadequate cooling at other operating points.
Monty