Conceptual Design of Subsonic Transport Aircraft for Cruising Flight Optimized for Different Merit Functions

摘要

An analytical approach to aircraft design optimization is presented. Design variables are mainly associated with wing design and powerplant sizing. Several figures of merit are studied as a function of the design variables and analytical expressions are derived for partial and combined optima. Merit functions are lift drag ratio, specific range, fuel plus powerplant weight as a fraction of the takeoff weight and of the design payload, fuel plus powerplant plus wing weight fraction, payload weight fraction, fuel burned per seat-km, and direct operating costs. The design variables studied are: engine size, (mean) cruise wing loading, pressure altitude, lift coefficient, Mach number, and wing aspect ratio.