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.

Induced-Drag Compressibility Correction for Three-Dimensional Vortex-Lattice Methods

Abstract: CD = drag coefficient CDi = induced-drag coefficient CD0 = zero-lift drag coefficient CL = lift coefficient CL ;c = compressible lift slope, 1= deg CL ;i = incompressible lift slope, 1= deg CP = pressure coefficient CP0 = incompressible pressure coefficient F = force, N k = induced-drag factor L = vortex segment direction vector M = Mach number Veff = effective velocity at vortex core, m=s Vrot = velocity induced by rigid-body rotations, m=s V = velocity induced by vorticity, m=s V c = velocity induced by compressible vorticity, m=s V1 = freestream velocity, m=s w = aerodynamic influence matrix = vortex strength, m=s = aspect ratio

Flight-determined low-speed lift and drag characteristics of the lightweight m2-f1 lift- ing body

Abstract: SUMMARY The low-speed lift and drag characteristics of a manned, lightweight M-2 lifting-body vehicle were determined in unpowered free-flight tests at angles of attack from 0" to 22O (0.38 radian) and at calibrated airspeeds from 61 knots to 113 knots (31.38 to 58.13 meters/second). pared with results from full-scale wind-tunnel tests of the same vehicle. Flight data are com- The investigation showed that 95 percent of the vehicle maximum lift-drag ratio of 2.8 was available through an angle-of-attack range from 4.4" to 14.6" (0.08 to 0.25 radian). be low in comparison with most other aircraft, no serious difficulties were experienced in landing the test vehicle. Although this lift-drag ratio is considered to The lift and trim characteristics were linear in the angle-of-attack range from 0" to 15" (0.26 radian). Although the same vehicle was tested in flight and in the wind tunnel, significant differences existed in the values of zero-lift drag and drag due to lift. INTRODUCTION In recent years, many wind-tunnel studies have been made during the development of lifting reentry configurations capable of gliding to a speci- fied recovery site and making a conventional horizontal landing. To comple- ment these studies, the

Drag Reduction for Turbulent Flow over a Projectile: Part I

Abstract: A numerical study is made to analyze the drag performance of a secant-ogive-cylinder-boattail projectile in the transonic Mach number regime between 0.91 and 1.20. To improve the projectile's performance, two drag reduction methods, boattailing and base bleed, are applied. The effectiveness of each method and the combination of both methods are studied by varying the values of parameters such as boattail angle, bleed quantity, and bleed area. The computed distributions of surface pressure coefficient of the projectile with different boattail angles are in close agreement with experimental data. Computed drag components and the total drag of the projectile are accurate by comparison with experimental data and semiempirical predictions. The optimal boattail angle for total drag reduction is predicted to be at about 5-7 deg. The method of combining boattailing and base bleed can become an effective method for total drag reduction.

Lift and drag characteristics and gliding performance of an autogiro as determined in flight

Abstract: This report presents the results of flight test of the Pitcairn "PCA-2" autogiro Lift and drag coefficients with the propeller stopped have been determined over approximately a 90 degree range of angles of attack Based on the sum of fixed-wing and swept-disk areas, the maximum lift coefficient is 0895, the minimum drag coefficient with propeller stopped is 0015, and the maximum l/d with propeller stopped is 48 Lift coefficients were found also with the propeller delivering positive thrust and did not differ consistently from those found with propeller stopped Curves of gliding performance included in this report show a minimum vertical velocity of 15 feet per second at an air speed of 36 miles per hour and a flight-path angle of -17 degrees In vertical descent the vertical velocity is 35 feet per second