"Robert Barker" wrote in message
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"Sliker" wrote in message
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I've got several buried antennas in my composite homebuilt. A com
antenna in the leading edge of the rudder, a VOR antenna in the outer
wing, and a com antenna along the side of the fuselage. One thing
occured to me was that if I paint my plane with a metallic paint,
would the metallic particles in the paint block radio reception?
I know the folks at the old Stoddard-Hamilton said after they built
the NASA funded, lightning protected Glasair 3, they had to move all
the antennas outside. And they also said they couldn't believe how
much better all the radios worked than before using buried antennas in
their original factory G-III. They also said the external antennas
cost them 10 knots in speed. Not insignificant. So even in an airplane
that's all composite, apparently buried antenna's aren't ideal. And
now I worry if I use metallic paint, things might get worse. I'm just
so sick of white airplanes, I'm not going that route. Maybe a light
gray instead of metallic silver as planned, hmm..........

A 10kt loss is relative. A 10kt loss in a Cessna 172 is a lot more
signifigant than a 10kt loss in a Lancair ES or a Glasair III. You could
lose 10kts in one of the latter in lots of other ways like fit and finish
or by going overboard and putting in a heavy interior.

That's quite true, but it is worth noting that the antennas usually sold for
lower speed aircraft have nearly as much drag at their lower rated speeds as
the faster speed antannas have at their rated speeds. The result is that
those little round antennas that you see on Cessna 152s and 172s may have at
least as much drag at a little over a hundred knots as the 600mph blades
have at 500kts. I don't know what is currently available, but if I was
personally putting external antannas on a homebuilt, I would certainly look
into it--and build my own antennas if I couldn't buy them at an acceptable
price.

Peter