Optimum Wing Area, Aspect Ratio and Cruise Altitude for Long Range TransportAircraft

摘要

An analytical method has been developed for calculating a Figure Of Merit (FOM)for long-range jet aircraft with engines sized for the cruise condition. This FOM represents the added weight fractions of the fuel load, the powerplant installation and the wing structure. Its minimum value results in a maximum of the payload fraction. Closed-form relationships were derived for optimum wing loading, wing aspect ratio, design lift coefficient and initial cruise altitude, for a specified cruise Mach number. Various combinations of partial and constrained optima have been derived both for given sweepback angle and (mean) thickness/chord ratio of the wing and for the case of constant drag rise Mach number parameters have to be matched to the lift coefficient. All results are illustrated for a hypothetical long-range passenger transport.