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Bill,
Good info in Peter's
site. But I wonder what would happen to the pressure plots if the front of the
cowl was streamline from the back of the spinner. Long ducts are possible from
the nose back to this location but if I understand correctly they would add
considerable drag. I like what Tracy is planning on his 8 but my supercharger is
in the way unless I use a long narrow radiator. My engine is 5" forward of
the IO540 + 3" for the prop with a 15" spinner.
Bobby
In a message dated 3/24/2006 8:12:29 AM Pacific Standard Time,
bhughes@qnsi.net writes:
Ernest,
RV10. Skinny
front tapered to the firewall. The sides are lower pressure
than the nose
on a conventional cowl. In this arrangement I think NACA's
may work
well.
Bobby
Bobby, Before going side INLET I suggest that you go to Peter Garrison's
site and check out his plot for his Melmoth 2 CFD. The plots won't be identical
to an RV-10 but are made on an aircraft of similar size and configuration. (4
seater standard Lyc engine etc.) We usually want our intakes in a HIGH pressure
area and exits in a low pressure area. You are correct that the sides of the
cowling are usually LOWER pressure than the front. Go to
www.melmoth2.com click on the topics
subhead and then CFD. He has had a close association with some really hot
designers like Rutan and John Roncz. Roncz ran his design through a high-end CFD
program in the design stages and this led to his unusual updraft cooling design.
Noting his cowl shape is fairly standard. Checking the pressure plots shows that
the sides might not be a good spot for the radiator intakes. Your radiator
locations aren't bad. This is the location I have considered for my rads as
well. but angling the "noses" in and applying duct work from a front inlet would
be a good idea. As Tracy says YMMV, but checking these pressure plots is a good
idea. I like the idea of side EXITS similar to the Thorp 18 since the area at
the rear of the cowling at the firewall is starting to go low pressure. Carefull
contour of the exit to place the exit air close to freestream angle would be
necessary as well. Of course the typical botton exit is also OK. Good
luck.
Bill Jepson
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