Aircraft Aerodynamics, Structures & Systems Module 13 B2, Book 1 of 9 ________________________________________________________________________________ ________________________________________________________________________________ Issue No. 0 Page 44 Date: January 09General The high lift required for the take-off and landing of large jet transports is normally provided by the combined effect of leading edge high lift devices and trailing edge flaps. Propeller driven types do not normally use leading edge high lift devices. Sufficient lift is provided by trailing edge flaps and the propeller slipstream over the mainplanes. For take-off the flaps are lowered to a small angle. This gives extra lift and a small increase in drag. For landing, the flaps are lowered too much larger angles to increase lift and drag which will help to slow the aircraft on the landing approach. Figure 42 Propeller Slipstream Increases Wing Lift Leading edge slats normally have two extended positions, take-off and landing. In the take-off position the slat is extended without forming a slot. Krueger flaps and variable camber flaps are either retracted of fully extended. They have no intermediate position. An aircraft will always take-off into wind, in order to reach flying speed with the shortest ground run. It will also land into wind so that it can touch down with the lowest ground speed. This will allow it to stop in the shortest distance.