On takeoff, we want high lift and low drag, so the flaps will be set downward at a moderate setting. During landing we want high lift and high drag, so the flaps and slats will be fully deployed.
People Also Ask
Q: When is it necessary to do full flaps for takeoff and when are minimal flaps needed? A: No airliners take off with full flaps. High-altitude airports and higher temperatures cause airplanes to use reduced flap settings to ensure adequate climb performance.
Most of the time, landing flap will be determined by the landing performance required, flap 30 is nearly always desirable unless we need the lower approach speed, or if increased forward visibility is required such as during low vis ops. Performance is the determining factor.
Full flaps increase drag more than they increase lift and is used to slow the aircraft for landing. Taking off with 10 to 20 degrees of flaps increases lift for takeoff without incurring a lot of drag, which you don't want for taking off.
Pilots usually use Flaps 1 when the weather is good for flying and if the runway used is longer than needed. Flaps 2 is used usually when headwinds are not strong enough or the runway in use is not that long for a takeoff run.
Short answer: Because planes are larger than birds. Flying by flapping their wings works very well for birds and insects. Machines that fly this way, known as ornithopters, have been built, some large enough to carry a man. But larger than that and the laws of physics become a serious problem.
Today's commercial autoland systems utilize the ILS (...) At around 30 ft above the ground, the aircraft enters the flare mode, during which the aircraft pitches up to reduce the vertical speed from its current descent rate to 1-3 ft/s by touchdown. Which means we're looking at 60-180 FPM touchdown rate.