-- 
Paul Lamar ...No rotor no motor.
------------------

Based on the temp drop of the oil, and the temp increase in the air; I am
currently getting 950 - 1000 CFM air flow through the core @ 160 mph.  Even
assuming an emissivity of 0.8; my calcs show that radiation heat transfer at
200F to be negligible - even if it wasn't in an enclosure.

Al



Lots of room heaters work this way. No fan. Convection currents only.

1000 CFM at one square foot oil cooler frontal area is 1000 FPM or 16 FPS or
11 MPH
air speed through the core. Sounds like convection currents to me.

Paul Lamar ...No rotor no motor.
-------------------

The cooler core area is 0.67 ft sq., velocity through the core is about 16
mph.  Natural convection is what I get on the ground - pretty close to zero.

Average velocity into the scoop entrance is about 55 - 60 mph

Al

How do you know? I did not see any pictures of pito tubes inside the
entrance. If so not much for 160 MPH forward speed.

At a forward speed of 80 MPH we were getting 24 MPH more or less evenly
distributed  across the back surface  of the core with this wedge diffuser.
-- 
Paul Lamar ...No rotor no motor.
---------------

Well; I know because I know I have about 1000 CFM, and I know the area of
the inlet scoop.  Note I said 'average' velocity.

True; it is clearly not much for 160 mph.

Yes, but see, I don't HAVE a wedge diffuser.  What I have is what I have;
and the first task at hand is to see if there is some reasonable way to make
it work.  As soon as I find some time, and get to the airport I can try some
things.
Al


Well Al let us know what you come up with. I am all out of suggestions.

-- 
Paul Lamar ...No rotor no motor.
---------------------

I will certainly keep you informed.  Your suggestion of changing the upper
contour of the duct certainly has merit, and I think it is something I can
implement in a temporary way to see its effects.

You asked about leaks at the top and bottom of the cooler. Yes there is a
small space (about 1/8" or less) between the sides of the cooler and the
enclosure.  This is there deliberately to isolate the hot cooler from, and
provide cooling for, the fiberglass and foam.  The gap extends the width of
the cooler, providing some pressure drop, but maybe less than through the
core, so I'm not much concerned about the amount of air that gets by.  But
does that change the dynamics of the diffuser?

Al

Sure will try plugging it with red RTV good for 500 F.
If you don't want the gooey stuff you can gets sheets of
it from McMaster.

That could be a major change.

-- 
Paul Lamar ...No rotor no motor.

Al,
The gaps can cause huge problems. On race cars we seal them tight as can be,
and a small leak causes problems. You have 2 23" x .125 gaps and that is
bleeding all your air pressure. As Paul recommended, seal them up with a
thermal barrier. The rtv will work, but do some research, I remember seeing
a paste with silicon and ceramic compounds that was flexible and has very
little thermal transfer.
Larry


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