Lift-induced drag

About: Lift-induced drag is a research topic. Over the lifetime, 2861 publications have been published within this topic receiving 41094 citations.

Flight-measured lift and drag characteristics of a large, flexible, high supersonic cruise airplane

Abstract: Flight measurements of lift, drag, and angle of attack were obtained for the XB-70 airplane, a large, flexible, high supersonic cruise airplane. This airplane had a length of over 57 meters, a takeoff gross mass of over 226,800 kilograms, and a design cruise speed of Mach 3 at an altitude of 21,340 meters. The performance measurements were made at Mach numbers from 0.72 to 3.07 and altitudes from approximately 7620 meters to 21,340 meters. The measurements were made to provide data for evaluating the techniques presently being used to design and predict the performance of aircraft in this category. Such performance characteristics as drag polars, lift-curve slopes, and maximum lift-to-drag ratios were derived from the flight data. The base drag of the airplane, changes in airplane drag with changes in engine power setting at transonic speeds, and the magnitude of the drag components of the propulsion system are also discussed.

A study of the minimum pressure in a trailing vortex system

Abstract: : Theoretical, experimental, and semi-empirical investigations of the minimum pressure in trailing vortex systems of elliptic, rectangular, and delta wings are presented. The magnitude of the minimum pressure coefficient in the trailing vortex system of a wing increases nearly linearly with the angle of attack of the wings. This magnitude is almost independent of aspect ratio for elliptic wings but for rectangular wings is slightly higher, the greater the aspect ratio, for a given angle of attack. At a given angle of attack the magnitude of the minimum pressure coefficient increases with increasing Reynolds number. The thickness of the tip-vortex core, or the thickness of the edge of the trailing vortex sheet is determined by the thickness of the boundary layer on the lower surface of the wing at the trailing edge of the tip and not be any considerations of induced drag and kinetic energy of the vortex sheet itself.

Optimal trajectories for maximum endurance gliding in a horizontal plane

Abstract: Nomenclature C0,C/,C2,Cj = constants of integration CD = drag coefficient CDO =zero lift drag coefficient CL = lift coefficient CL* = lift coefficient for maximum lift-to-drag ratio D = drag force E* = maximum lift-to-drag ratio h = altitude H =Hamiltonian function kj,k2,k3 =constants, =C//C0, C2/C0, C3/C0, respectively K = induced drag factor L =lift force m =mass of the vehicle Px>Py>Pu>Pt>Pe = adjoint variables associated with state variables r — radius of penetration 5 = reference area / =time u = dimensionless speed V — speed of vehicle W — weight of vehicle x,y = dimensionless coordinates X,Y = position coordinates of vehicle A =tan/>t 0 = dimensionless time X = normalized lift coefficient jn =bank angle p = density of atmosphere T = normalized time 0 = velocity yaw angle co = dimensionless wing loading

A technique to determine lift and drag polars in flight

Abstract: : Performance trials of the European combat aircraft TORNADO have concentrated on the systematic measurement of lift and drag polars. Such polars have been successfully measured by means of well-adapted test instrumentation, a data reduction system, and a high calibration standard of the aircraft and engines. The use of a certain combination of steady-state and dynamic test maneuvers has resulted in a drastic reduction in the amount of flight time required to obtain sufficient data for the determination of the zero lift drag, induced drag characteristics and drag increments due to aircraft configuration changes. Flight test results are presented which demonstrate the advantage of the test technique used and the high data quality achieved.