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Bobby, I am familiar with Ross's RV-10 project, and I think he will be successful, BUT that is absolutely NOT a P-51 type scoop. It is a belly scoop that resembles a P-51 scoop. He is exhausting the air directly out the back and the radiator is nowhere near as inset as a '51. As Ed mentioned the North American team changed the scoop at several times, before getting the best defuser shape and radiator configuration. I would consider putting in a tank for spray bar water if you are forced to idle on the ground frequently where you are. The ability to have a closeable rear flap with a streamlined exit will help a bunch. The Lancair is a better candidate for this type of scoop since the strength is in the skin. I didn't think anybody would be willing to modify the floor of the RV-10 as there are a bunch of rib/bulkheads near the rear of the fuselage. Ross at SDSEFI got around that by keeping the scoop mostly external.
Bill Jepson
BTW i believe that Ross scoop started life as a ProStock hood scoop.
-----Original Message-----
From: Bobby J. Hughes <bhughes@qnsi.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Fri, 29 Feb 2008 1:56 pm
Subject: [FlyRotary] Re: New (old) guy on list
RV10, P51 radiator arrangement. http://www.sdsefi.com/air46.htm
This project has not flown yet but it does look interesting.
Bobby
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Ernest Christley
Sent: Friday, February 29, 2008 3:42 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: New (old) guy on list
Greg Ward wrote:
> MessageI would also be really interested in seeing some others cooling
solutions. I was told that 40% of the Lancair's drag is in the cooling
drag, and I am contemplating a belly scoop A la' P-51, and have created
controversy about how much that configuration will add to the drag
factor. In other words, I might get great cooling at a slower speed?
Supposedly the P-51 configuration creates enough thrust to overcome
around 90% of the drag created, but I would like to confirm that before
I go through the process of designing and building the damn
thing.......(:-) Call me lazy...
> Greg Ward
> 20B Lancair in Progress
>
My survey of the studies and anecdotal evidence that I could find,
indicate fairly conclusively that radiators inside the engine cowl is
about the worst possible option when considering cooling drag. However,
for many it is the only option, and for most it is by far the easiest
option. The planform of my project is completely different than most,
giving me a relatively easy option of installing the rads and ducting
within the wing's 18" thick airfoil. I'm not even fantasizing that I
will wind up with net positive thrust, just confident that it won't be
quite so negative.
With a conventional planform, how would you seperate the hot tube from
the fleshy parts of the airplane? Long hose runs will be heavy,
especially if you use 1" hose to keep a reasonable flow. And the
placement of the weight could possibly play havoc with your W&B (it was
actually a slight improvement for my situation).
One thing is very clear, though. If you can make it work, it'll be one
of the sweetest looking Lancairs on any field it visits.
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