> >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

Thanks Bill I will add that to my list of surprises.  Of course the
fan maker says the fans have no effect on airflow when they are idle.

Paul,  the blue foam you mention, is that styrofoam or polystyrene?
When it comes to composites I am a total beginner.  I feel it is time
for me to learn these skills.  There are many books and videos on the
subject-- is there one you would recommend?  Jerry

Styrofoam is polystyrene and you must use epoxy resin with it.
Polyester resin (boat resin) will melt it.

Paul Lamar
 
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