Mal Booth wrote:

Paul,
    What we are currently considering is a pointy nose and an inlet each
side of the fuselage behind the doors,- at the widest point like "ears".
Ducts will take up some luggage space behind the seats but can be made long
enough. Inlets here will be protected from spray if floats are ever an
issue. Outlet(s) can be under TAILPLANE!!. Any advice?.
        Cheers, Mal Booth
----- Original Message -----
From: "ACRE" <rotaryeng@earthlink.net>
Sent: Saturday, April 02, 2005 10:45 AM
Subject: Duct shape

Ian Beadle wrote:

Hello Paul
In your script on cooling you refer to diagrams z, r, and s in
relation
to heat exchangers at an oblique angle. Could you post them for me
please.

Ian Beadle

The curved one is figure r.
The wedge is figure s.

Can't find z :)

Paul Lamar

Mal Booth wrote:

Hi Paul,
      These are the diagrams I asked for earlier, many thanks for the
pics.
Could you also please clarify what is meant by "bell-shaped" in the
same
article?. It would seem that both an internally "convex" duct & an
internally "concave" duct could both be described as "bell-shaped",-
if I
make myself clear.

Yes you are right about that. I should not use the term "bell shaped".
I
should
say trumpet shaped.

There is no room in our airplane for a true trumpet shaped Kucheman &
Webber
style duct unless it goes in the aft fuselage. The duct length needs to
be
2.5 times the rad dimension.

Paul Lamar

Mal Booth wrote:

G'day Paul,
    Thanks for that clarification, it has worried us for a long time. We
are
trying to design a cooling system as per your earlier recommendations
with a
rear fuselage radiator, long inlet duct with minimal entry & long
"tailpipe"
with variable exit area similar to the 1939 "Napier Heston Racer". Did
the
photocopies of this ever reach you?
     The slide throttles look great,- looking forward to the day we need
'em!
                Cheers,
                      Mal Booth

The only drawbacks to the rad in aft fuse is: A. the structure must be
designed for
it and B. The increased frontal area of the P51 type duct required.
That is why we try to keep the rads up front in the cowl. It makes more
sense for a narrow tandem seat airplane with limited cowl room.


Paul Lamar

That would add to the frontal area. The frontal area is the maximum cross
sectional area of the airplane. Not necessarily at the front.
The drag is directly proportional to the frontal area. So too the MPG.
Best to put the rad under the cowl since the rotary engine is so small.

Paul Lamar
 
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