THE UNIVERSITY OF NEWCASTLE AUSTRALIA AERO2000 Tutorial Week 12: Descent, Take-off, Landing and The Flight Envelope Descent (glide) performance Exercise 1 A glider weighs 800 lbs and has a wing loading of 12 lbs/ft. Its drag polar is: CD = 0.0100 + 0.0220 C Assume that the glider is launched at 1,500 ft in still air and over level ground. Assume standard atmospheric conditions. Calculate the following: 1) the greatest distance it can cover along the ground (Ans. R = 9.6 miles) 2) the speed at which the aircraft has to fly to cover this distance (Ans. V = 122.35 ft/s) 3) the speed at which it has to fly to stay airborne for this time to achieve the longest duration in the air (Ans. V = 92.97 ft/s) 4) the longest duration the aircraft can remain airborne (Ans. E = 7.9 mins) Assume that the effect of changing density can be neglected. Exercise 2 The maximum lift-to-drag ratio of the World War I Sopwith Camel was 7.7. 1) If the aircraft is in flight at 5,000 ft when the engine fails, how far can it glide in terms of distance measured along the ground? (Ans. R = 729 miles). 2) Calculate the equilibrium glide velocity at 3,000 ft, corresponding to the minimum glide angle. The aspect ratio of the aircraft is 4.11, the Oswald efficiency factor is 0.7, the weight is 1,400 lb, and the wing area is 231 ft. (Ans. V = 97.2 ft/s). 1