WingFlaps wrote:
On Mar 14, 9:11*am, Brian wrote:
As for your question above, given that the airplanes are ascending or
decending at constant rates then the lift is equal to the wieght of
the airplane in both cases. If the aircraft are the same wieght then
the lift generated will be the same.


That is not correct.

Hmmm. Brian's statement appears essentially correct - and you are correct
too. The "gotcha" is that the vertical component of the lift force exceeds
the weight only during the transition from level flight to constant
ascending flight. And the lift force is less than the weight during the
transition from level flight to constant descending flight.

But once the vertical speed becomes constant (whether up or down) the
vertical component of lift has to equal the downward force of gravity. If
it didn't, then the aircraft would begin _accelerating_ up or down,
depending on the difference.