I agree with your statement, but I don't know where the center of lift
is on GA airplanes, hence the question. Maybe it would have been
better to ask a center of lift question. The loading moment is
calculated from an arbitrary datum, it would be neat if there was an
easily identifed point that corrosponded to the center of lift.

On Nov 2, 5:52 pm, wrote:
On Nov 2, 7:12 pm, Tina wrote:

OK, so the center of gravity (except for some airplanes with really
smart computers) is going to be forward of the center of lift for
stall recovery reasons -- that makes sense. The question I have is,
for a typical GA flying machine -- take a complex single for example
-- what really is the download (I'm thinking of it as induced weight
with fuel burn consequences) supplied by the vertical stabilizer? It
has a reasonable moment arm hanging way back there, but is it as much
as say 100 pounds if the CG is near the forward limit?

This isn't an aeronautical problem, its a basic mechanics problem.
The moment of the CG vs. the center of lift must equal the moment of
the tail plane.

If the airplane gross weight is 2500 lbs, and the CG is 1 foot in
front of the center of lift, that is a moment of 2500 foot-lbs. If
the tail plane is 10 feet behind the center of lift, the force on the
stabilizer is 250 lbs.

Dean