Jerry Hey wrote:

After weeks (months) of vacillating, I  decided to move the rad to
the very rear of the baggage compartment.  At the same time I moved
the battery from the baggage compartment to the engine side of the
fire wall. With this arrangement  there is nothing of consequence
going on with the c.g.  I liked the idea so much that I went ahead
started  the installation.  I'm attaching a few pic that may or may
not be if interest.  Also attaching a drawing of my proposed inlet
scoop.  You will see that it has a generous air bleed.  Gone forever,
I think, are the submerged inlets that I wanted so much.
Please do your usual red pencil critique of the drawing.  Thanks,  Jerry

Looks like it will work fine Jerry. Streamline the boundary layer
air bleed and use a lip on the intake with about a 1/2 or more radius.

BTW if you carve this in blue foam you can use model airplane
low temp econocoat ironed on as a parting agent and for smoothing
the male mold for a fiberglass part. It will look better than sheet metal.

Paul Lamar

  Jerry,

You're getting there!  I like this iteration, good picture, too.

If you put a central point tapering to the sides between the scoop
and the belly, you will divert the boundary air away with less drag
than without it.  Imagine a "V" pointed forward with the 'point'
about a inch behind the inlet lip, and nearly as wide as the duct -
extrude this shape vertically to fill the gap between the scoop and
skin of the fuselage. It dumps the low speed boundary air to the
sides with lower drag penalty.

Looks pretty good.  I worry that the large blocked off areas in the fan
shroud may reduce the radiator effectiveness at high speed cruise conditions.
I assume that the fans are on the downstream side.  You might
consider cutting away most of the material in the "blocked area"
(upper right) and making it into a blow out door that can open with
the slightest pressure (literally < 0.1 psi) to permit less flow restriction
at high speed cruise condition.  When the ram air is low and you need
the fans, the downstream side of the rad will be a low pressure area (due
to the fans) and will suck the door closed and permit the fans to work
effectively.   This type of blow-out doors were added to the radiator fan
shrouds of high performance Corvettes in Europe some years ago as
the fan shroud restricted the air flow out of the rad at the very high cruise
speeds possible legally in Germany and other places.  Without the blow
doors the cars overheated at sustained high speeds even though the radiator
was adequate.  The doors closed with springs to permit the engine driven
fan to be effective at low speeds.

Bill Freeman

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