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Old December 6th 06, 01:33 AM posted to rec.aviation.piloting
Allen[_1_]
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Default Does the elevator/stabilator generate upward force?


wrote in message
oups.com...

Allen wrote:
wrote in message
ups.com...

Allen wrote:

I once saw a pair of mechanics doing a full power run-up in a Maule.
They
were holding brakes on and forward elevator, the tail was about six

feet
in
the air standing still. So yes. Why do you separate the nosewheel

from
the tailwheel? They both fly with the same principles.

Allen

Aha, but you have to allow for the thrust line being so far
above the drag line, which in this case is the ground where the wheels
are locked. That thrust produces a pitching couple that raises the

tail
much more effectively than the down-elevator. If the pilot holds full
forward elevator at the start of the takeoff roll, the tails of most
taildraggers won't come up until some considerable forward speed is
attained, and then the tail is rising mostly because the centre of
pressure of the wing, being behind the mains, is lifting it. Using
forward elevator will lift the tail sooner but it sure is not entirely
responsible for the rise.
Wheelbarrowing is also mostly caused by too-fast landing
speeds, not just forward elevator. It's worse with flaps down because
the wing's CP is ahead of the mains and is raising the tail.
Down-elevator isn't even necessary at high-enough speeds. The
nosewheels of most trikes is closer to the ground than the mains in
level flight attitude, and will contact first with the high airspeed
reducing AOA.

Dan (Instructor in taildraggers and trikes and a mechanic too)


I have seen a Super Cub land with a 40 knot (or so) headwind and come to

a
complete stop, then raise the tail off the ground with the engine at

idle.
I see you point about the thrust affecting pitch though, used that all

the
time landing the Lear, as you bring the power levers to idle the nose
pitches up and automatically puts you into the flare.
Allen


But that 40-knot headwind is still lifting the wing, even with
the airplane motionless, making it very easy for the elevator to LIFT THE

TAIL. The airplane is almost flying.

Dan

Ah ha, the answer to the OP's question.

Allen