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Aerodynamics of the 737-300

Contributed by Nick Duros
Saturday, 21 January 2006
Page 8 of 10 14. Change in power required with change in weight A change in weight will change the amount of power required. With less weight, less lift needs to be produced and the engine thrust can be retarded. The equation requires the Pr to be in HP, so the thrust of 4,650 is converted to 6,238 horsepower. HP= T V_k 325 HP = 4,650 * 436 325 HP = 6238 The change is weight from 124,500 to 100,000 shows the decrease in power required from 6,238 to 4,490 hp. The change in velocity due to a change in weight at 30,000 feet is as shown: when the weight is at 124,500 pounds and the velocity is 436 knots, the change in velocity is 391 knots when the weight is reduced to 100,000 pounds. The following shows the change in velocity at 10,000 feet at 124,500 pounds at 320 knots, with a change in weight to 100,000 pounds which equals a new velocity of 257 knots. 15. Change in takeoff velocity with change in weight Changing the weight of the aircraft will change the takeoff velocity. The lighter the aircraft is, the less weight which the component of lift has to overcome. The aircraft must overcome the increased mass during the acceleration, and there is increased rolling friction. The 737-300 at 100,000 pounds will require a takeoff speed of 142 knots, increasing the weight to the maximum takeoff weight will require a speed of 158 knots. In addition, the landing distance at 124,500 pounds will be 6,000 feet if the takeoff weight is decreased to 100,000 pounds the takeoff distance will be 3870.91 feet. This is the Takeoff Field Limit chart. This shows the takeoff performance at a particular weight and its corresponding speed. Additional information is provided showing the stabilizer trim setting, slope adjustments, wet runways adjustments on takeoff performance. 16. Change in landing velocity with change in weight The speed at which an aircraft lands also depends on the weight. The heavier the aircraft the more weight will need to be supported by the component of lift. The change in weight from maximum landing weight, 114,000 pounds, to 100,000 pounds changes the landing velocity from 136 to 127. << Start < Previous 1 2 3 4 5 6 7 8 9 10 Next > End >>