On Apr 25, 11:23*pm, Stefan wrote:
WingFlaps schrieb:

A direction change in a
plane is always due to acceleration (and that means more drag). That's
Newtonian physics.

Right.

You go from up wind direction (takeoff is usually
up wind) to turn in the wind direction to land down wind. There's an
acceleration, it is a change in _velocity_

Wrong.

it creates drag, it costs
height and that's the important bit. Now do you understand -TURNS are
not free,

Right.

Your're mixing up two completely different things. Of course, turns are
never "free". They cost energy due to higher drag, resulting from higher
speed, higher wingload and control deflection.

I'm not mixed up, You wanted to read something into what I wrote that
was not there and try to score some point I think Well you were wrong
and you still are. I never said airspeed did I?

One last time, as succinctly as I can: to change direction requires
more energy as extra drag = k.m.dV/dt. dV/dt is acceleration and that
is precisely the term I used. The aircraft does _accelerate_ into the
downwind direction. Airspeed may not change but _velocity_ sure as
hell does -'cos IT'S A VECTOR. Now, the energy needed for the change
in _velocity_ comes from the loss of height during the turn and that's
easy to calculate. It is much harder to estimate the extra drag loss
as this will depend on pilot skill and aircraft design. I hope you
finally understand, cos I'm really starting to find it tiresome trying
to explain to you some basic physics which you seem intent on mis-
interpreting.

I'll give you this last post, any continuance along your previous
lines of putting erroneous words into my mouth I will take as your
being a troll...

Cheers