Comparison of business jet performace using different strategies for flight at constant altitude

A model for the aircraft performance including a Brayton turbojet engine cycle analysis was developed in order to study the effect of different flight profiles on the range of a medium-sized business jet. In the classic flight mechanics treatment of aircraft performance, maximizing range requires maximizing C_L^1/2/C_D. This classic approach, however, assumes that thrust specific fuel consumption is a constant. Past studies which include the effect of variation in thrust specific fuel consumption typically seek to determine the optimum flight Mach number under a constant altitude - constant speed flight condition. Actual aircraft, on the other hand, may involve fixing the engine throttle or thrust output to a set value and allowing the aircraft to speed up as the weight decreases. This project is motivated by a desire to study what effect variations in flight conditions such as speed, lift-to-drag ratio, throttle, or thrust settings have on aircraft performance. An increase in range of about 2% was obtained by maximizing U(L/D)/TSFC compared to the case where C_L ^1/2/C_D is maximized.