On Apr 12, 2010, at 6:24 AM, david miller wrote:
> I think that for most efficient flight the incidence of the wing and
> tail should be such that at cruise there is no up or down trim on
> the elevator or all flying tail.
Fascinating discussion...as a non-aerodynamicist, I can't resist the
temptation to add a comment...
I've always understood that the elevator or an all-flying tail
(horizontal tail plane) has a "job"...namely, to exert a force, either
up or down, in order to balance the lift of the wing and stabilize the
flight path of a normally configured aircraft (i.e., not a canard
type). To do this "job" requires "work"; the tail plane is never
neutral. And w/ our Europae...with it's trim tabs acting in
opposition to the all-flying tail plane thru a direct mechanical
connection...whenever the tail plane is doing its job (at whatever
angle of incidence), the trim tabs will be doing their job as well
(that of counterbalancing forces on the tailplane), and will
necessarily be raised or lowered w/ reference to the tailplane.
Of course if this explanation is correct, one might ponder the
aerodynamics of my tail-less biplane...pix below.
Fred
|