Squared trailing edge of control sufraces

In the eighties Grumman AA5 aircraft had an aileron flutter problem
and one of the fixes was to chop off the rear of the aileron and make
it square,,,the other was to replace the rubber bushings holding the
tourque tubes to take out the play.

ray


On Wed, 27 Jul 2005 16:16:21 -0500, Don Hammer
wrote:

I believe the Cessna Citation has a "T" shaped
piece inserted in the trailing edge of the elevator or rudder (could
be both)

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

It's on the rudder on the smaller Citations. The purpose is so there
is no hard spot when the rudder is centered at high speed. On
aircraft with non-boosted controls, they droop the ailerons for the
same reason

It proved to provide a big drag reduction on the G-550 to square up
the IB flap TE as compaired to the GV. Global Express as well as
Citation X have them squared also.

Do a Google search for Kamm Effect and you'll find things like -

It was once thought that a long tapered end in the shape of a vehicle
would give it the most aerodynamic configuration. W. Kamm discovered
that the length of the end would have to be so long as to make the
vehicle impractical. There would also be an increase in surface area
which would also create its own frictiondrag. He found that if he cut
the theoretically long tail in half he would have both good
aerodynamics and minimal surface drag. This sharply cut off rear end
is named after him.

Seems to me that since drag goes up squared with the speed that it
would work the best at higher speeds.