Pressure Differential in heat Exchangers

And several more who have just sealed the radiator to the bottom of the
cowl. Cut a hole in the cowling for the radiator exhaust air to exit;
placed a lip at the front edge or several rear facing louvers over the
opening and it cools....even bringing with it all that hot air radiating
from the engine exhaust pipes (though temps are higher than setups using
a dedicated duct system).

Many different styles of radiator arrangement have worked...radiators
behind the engine, under the engine, above the engine, even in front of
the engine...the common element is exhausting that hot radiator air into
a low pressure area. I have talked to builders who were absolutely vexed
and ready to abandon the project. In most cases simple installation of a
2" lip on the leading edge of the exit opening completely solved the
problems.

Let me add that the dedicated duct offers a better opportunity to
control temps and drag, but many arrangements have worked exceedingly
well...even radiators mounted behind the baggage compartment (Blanton's
original design with the V-6 STOL)

Corky Scott wrote:
Me too. I've got a video at home that was produced by Jerry
Schweitzer. He used to build Ford V-6's for people to use for auto
conversions, don't know if he does that anymore. He had two airplanes
that were Ford powered, a Pacer and an RV-4.

The video I have is about the Pacer installation. In it, the radiator
is mounted flat underneath the engine. It's a pretty big sized
radiator. The air is drawn through the stock openings in the chin
cowl, passes by the PSRU, which is good because it needs to have
cooling air going over it. Then the air has to get around the engine
and the hot exhaust pipes and THEN pass through the radiator and
remove heat from it's fins.

But we aren't done yet. After that convoluted journey, the air then
has to bend 90 degrees to head out the exit, which is just a hole in
the bottom of the cowling underneath the firewall. The hot air exit
had a lip in the front of the opening to promote a low pressure area
right around the opening.

Despite all the problems with this layout, it not only worked, it
worked well.

Corky Scott


--
Bruce A. Frank, Editor "Ford 3.8/4.2L Engine and V-6 STOL
Homebuilt Aircraft Newsletter"
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| on all aspects of alternative |
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