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Ernest,
...... There is a subtle
difference between "supplying air to a radiator" and "using a NACA inlet
for pressure recovery." The subtlety is the root of the argument. Just
because it isn't good a pressure recovery doesn't mean that it will make
a bad cooling inlet. It only means that you will have to do some
pressure recovery in some other way, like a streamlined duct. "We don't
THINK it will work for radiators, because there isn't enough pressure
recovery" IS a long way from "it can't supply air to a radiator and you
shouldn't waste your time trying ***because the inventors said so***".
I'm only objecting to the very last clause. The authors might fully
agree that a submerged inlet is a perfect compliment to a streamlined
duct. The submerged inlet collects air in a low drag manner which it
does well, and the streamline duct is responsible for pressure recovery
which IT does well. But we don't know that, 'cause they don't make any
attempt to speak to it. I think it would be appropriate to assert that
the authors would agree with the statement that sticking a radiator
against the back end of a NACA inlet is only marginally better for
cooling than hanging it out the bottom of the fuselage.
.........
That's precisely what I want to test sometime!
Intuitively I'd rather lean towards a ram intake with a streamline diffuser,
followed by some kind of suction exit (exhaust augmenter or just
slipstream).
But it might be a 50/50 game at the end...... as you said, at the end one
has to look at the whole system not just ata single part!
I really started to get interested in all that diffuser stuff after reading
about Dave Anders RV-4 (Cafe Foundation) and Brian Schmidtbauer's Mustang II
( Kitplane Feb.2004). They also point to Hoerners books (Fluid dynamic drag)
and came up with a intake/outlet ratio of 78% - intake being bigger (comon
practise was outlet 150% of inlet...)
I still didn't find the part about the P-51 with the modified cooling-scoop,
the one more efficient, but still didn't make production...
....and all to reduce cooling drag (which is a big performance eater if not
kept at bay)
Thomas J. :)
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