Originally Posted by AirGek
I came across this yesterday when reading "Ace The Techincal Pilot Interview". The query was "During what phase of flight is lift the greatest?" and the answer was "In general, the takeoff".
In general? Not a chance. Generally lift is greatest in rapid pull-ups or very steep turns. To achieve 60° bank coordinated turn one needs 100% more lift than weight while at typical (that is: not VMCA limited) take-off safety speed highest possible achievable lift exceeds weight by mere 44%. Even moderate turbulence will give you (briefly) greater lift than just taking off. Methinks the author of this pamphlet masquerading as a serious book here had a case of extreme narrow-mindedness and focused on the case of ideal airliner flying in ideal atmosphere - now that would make his statement true.
I wonder why in the world people keep insisting on reading this faulty book?
Why does aircraft take off?
Depends on the type of the aircraft but there always has to be force opposing and greater than weight to accelerate said aircraft upwards. Airliners climb at (relatively) shallow angle and have low thrust-to-weight so while their engines contribute to total upwards force, aerodynamic lift is main culprit.
As weight reduces (fuel burn off), so does the lift required to hold the thing up in the air.
We have more uses for lift than simply keeping the aroplane in the air. E.g. turning.