Good discussion Eric, Larry & others. There is one point that I haven't seen
mentioned in this whole drag reduction thread though. Yes, the tail plane
produces a downward force (necessary for stability) and of course, things
can be tweeked to minimize the drag that the tail plane produces. The
missing point is that the "weight" of the tail down force must be lifted by
the main wing. It is here, in the wing, that you would see the most drag
reduction from minimizing tail down force.

Moving the CG forward requires more tail down force to balance. The
additional tail down force must be lifted by the wing exactly as if it were
"real" weight. At a given airspeed and weight, the aircraft with a more
forward CG will be flying at a higher angle of attack and producing more
induced drag.  Conversely, moving the CG aft will reduce the required tail
down force, lower the total lift requirement of the wing and allow it to fly
at the same airspeed with a lower angle of attack and therefore less induced
drag.

Remember day one of primary ground school? In unaccelerated flight lift =
weight?  Ain't so (unless you define "lift" as the net lift of the wing
minus the tailplane).  Lift, as produced by the wing, is greater than weight
by an amount exactly equal to the tail down force.


Bill
harrelson@erols.com
N5ZQ  LNC2  O-320  VA42  Fredericksburg, VA