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Aerodynamics of the 737-300

Contributed by Nick Duros
Saturday, 21 January 2006
Page 4 of 10 6. High Coefficient of Lift Devices: Lift Devices Introduction The high lift leading edge devices are used in combination with the trailing edge flaps to increase lift during takeoff and landing. The trailing edge flaps and leading edge devices, when extended, increase the wing chord and camber, which greatly increases lift, providing slower approach speeds and greater maneuvering capability. Trailing edge flap positions from 0 to 15 provide increased lift with relatively little increase in drag, while drag rises more rapidly than lift for positions greater than 15 and up to 40. Auto Slat System The auto slat system provides improved handling qualities at high angles of attack during takeoff or approach to landing. When trailing edge flaps 1 through 5 are selected, the leading edge salts are in the EXTEND position. As the airplane approaches the stall angle, the slats automatically go to the FULL EXTENDED position, prior to stick shaker activation. The slats return to the EXTEND position when the pitch angle is sufficiently reduced below the stall critical attitude. Leading Edge Devices The leading edge devices consist of 4 flaps and 6 slats. Two flaps are inboard of each engine and 3 slats are outboard of each engine. Flaps are hinged surfaces that extend by rotating downward from the lower surface of the wing leading edge. Slats are sections of the wing leading edge that extend forward to for a slotted leading edge. 7. Drag Inducing Devices Speed Breaks The flight spoilers are used as speed breaks in the air, and both flight spoilers and ground spoilers are raised to reduce lift and for aerodynamic breaking on the ground. In Flight Operation By actuating the speed break lever, all flight spoiler panels will rise symmetrically in incremental amounts to act as speed breaks. In a turn, the spoilers will greatly increase the roll rate. Spoilers Flight spoilers rise on the wing with up aileron and remain faired on the wing with down aileron. 8. Drag Drag is the aerodynamic force that acts parallel and rearward of the direction of flight and a factor an aircraft must overcome for flight. The drag at 30,000 feet is 4946.27 pounds and at 10,000 feet, the drag is 4626.26 pounds. At 30,000 C_d needs to be found to complete the drag equation V= 436 knots S= 1135 ft q= 256.35 (from question 2) C_D= 295d &sigmaV²S C_D= 295 4650 .3741436²1135 1371750 = .017 80715426.94 D=C_DqS D=.017256.351135 D= 4946.27 lbs of drag At 10,000 V= 320 kts S=1135 q= 254.75 (from question 2.) C_D= 295d σV²S C_D= 2954650 .7385320²1135 1371750 =C_D 85831424 C_D= .016 D = C_DqS D = .016 * 254.75 * 1135 D = 4626.26 Lbs of drag << Start < Previous 1 2 3 4 5 6 7 8 9 10 Next > End >>