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Old July 3rd 03, 04:50 AM
Bruce A. Frank
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The fans that wear out seem not able to take the thrust loading of being
spun by the air load, but as I said, the one in Bayard's Defiant had no
problems. You may be correct that those other systems had too high air
velocity.

Morgans wrote:
"Bruce A. Frank" wrote in message
...


Morgans wrote:

Why not use a little electric fan to draw air past the radiator for


extended

ground operations, like cars do?


It has been done. Bayard DuPont did it on the rear engine in his Defiant
and it worked well. Others who tried it found problems with ram air in
flight spinning the fans and wearing out the bearings.



Seems to me that if the fan was spinning so fast that it is wearing out
bearings, the air speed past the radiator is waaaaaay to high. Design the
inlet (read small and divergent ducts) so that it keeps the air speed past
the radiator low at cruise speed, and then plan on using the fan for ground
operations, and climb, if need be.

As far as pushing air, I know that it needs to be drawn through to an area
of lower pressure; that's what the fan on the back side of the radiator is
all about.

See any flaws in my reasoning? BOb, I know what you have to say; that the
idea of using anything other than a lycosarus is a flaw! ;-)



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Bruce A. Frank, Editor "Ford 3.8/4.2L Engine and V-6 STOL
Homebuilt Aircraft Newsletter"
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