Reduction Of Drag Due To Lift At Supersonic Speeds
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| Author | : Douglas Aircraft Company |
| Publisher | : |
| Total Pages | : 124 |
| Release | : 1955 |
| Genre | : Aerodynamics, Supersonic |
| ISBN | : |
$EVERAL TOPICS RELATING TO THE REDUCTION OF DRAG DUE TO LIFT AT SUPERSONIC SPEEDS ARE DISCUSSED. The distribution of camber for optimial loading of diamond planform wings and some low drag geometries for rectangular wings are determined. It appears that substantial drag reduction, through the use of spanwise distribution of camber, may be achieved only for low reduced aspect ratios, M2-1 AR. The distribution of lift throughout volumes of prescribed shape is considered and some optimum distributions found for certain cases. It is shown that optimum spatial distributions of lift arc generally not unique. The possibility of using biplanes is explored and it is concluded that for non-interfering biplanes (wings acting as isolated monoplanes) there is an inherent structural advantage which is the result of a scale effect for geometrically similar structures The preacnt status of means for drag reduction is surveyed and the direction for further study indicated.
| Author | : |
| Publisher | : |
| Total Pages | : 28 |
| Release | : 1966 |
| Genre | : |
| ISBN | : |
| Author | : Robert S. Osborne |
| Publisher | : |
| Total Pages | : 20 |
| Release | : 1960 |
| Genre | : Aerodynamics |
| ISBN | : |
| Author | : Richard T. Whitcomb |
| Publisher | : |
| Total Pages | : 20 |
| Release | : 1960 |
| Genre | : Airplanes |
| ISBN | : |
Summary: As an extension of the transonic area rule, a concept for interrelating the wave drags of wing-body combinations at moderate supersonic speeds with axial developments of cross-sectional area has been derived. The wave drag of a combination at a given supersonic speed is related to a number of developments of cross-sectional areas as intersected by Mach planes. On the basis of this concept and other design procedures, a structurally feasible, swept-wing--indented-body combination has been designed to have relatively high maximum lift-drag ratios over a range of transonic and moderate supersonic Mach numbers. The wing of the combination has been designed to have reduced drag associated with lift and, when used with an indented body, to have low zero-lift wave drag. Experimental results have been obtained for this configuration at Mach numbers from 0.80 to 2.01. Maximum lift-drag ratios of approximately 14 and 9 were measured at Mach numbers of 1.15 and 1.41, respectively.
| Author | : M. E. Graham |
| Publisher | : |
| Total Pages | : 104 |
| Release | : 1960 |
| Genre | : Drag (Aerodynamics) |
| ISBN | : |
| Author | : Richard M. Hartley |
| Publisher | : |
| Total Pages | : 36 |
| Release | : 1965 |
| Genre | : |
| ISBN | : |
An unswept 12-percent-thick wing panel (NACA 0012 section) was tested with a wedge protruding from the blunt leading edge to determine if wing drag could be reduced and lift-to-drag ratio improved at a supersonic airspeed (Mach number 1.87). The wing and wedge were also tested at low subsonic airspeeds to determine if a slat effect existed which would increase maximum lift. At the supersonic airspeed, the wedge reduced the drag of the plain wing by as much as 29 percent at low angles of attack. At higher angles, this drag reduction vanished but the wedge still increased the maximum ratio of lift to drag by as much as 20 percent. At low speeds, a wedge slat increased maximum lift by as much as 54 percent. A small cambered airfoil slat (with a somewhat larger chord than the wedge) was able to increase maximum lift by 72 percent. (Author).
| Author | : Edward C. Polhamus |
| Publisher | : |
| Total Pages | : 28 |
| Release | : 1953 |
| Genre | : Airplanes |
| ISBN | : |
| Author | : A. J. Eggers (Jr.) |
| Publisher | : |
| Total Pages | : 42 |
| Release | : 1956 |
| Genre | : Aerodynamics |
| ISBN | : |
Summary: The problem of designing an aircraft which will develop high lift-drag ratios in flight at high supersonic speeds is attacked using the elementary principle that the components of the aircraft should be individually and collectively arranged to impart the maximum downward and the minimum forward momentum to the surrounding air. This principle in conjunction with other practical considerations of hypersonic flight leads to the study of configurations for which the body is situated entirely below the wing; that is, flat-top wing-body combinations. Theory indicates that sensibly complete aircraft of this type can be designed to develop lift-drag ratios well in excess of 6.
| Author | : Robert T. Jones |
| Publisher | : |
| Total Pages | : 28 |
| Release | : 1947 |
| Genre | : Airplanes |
| ISBN | : |
Recent developments in supersonic flow theory are applied to obtain estimates of the lift-drag ratios that may be achieved by aircraft employing swept-back wings. Lift-drag ratios greaterr than 10 to 1 can be maintained up to a Mach number of 1.4 bythe use of large angles of sweep and high aspect ratios. As the speed increases in the supersonic range the attainable lift-drag ratios decrease and the gain due to sweepback also appears to diminish. An efficient configuration for M = 1.4 would require about 60 degrees sweepback, an aspect ratio of 4 and a wing loading of one-third the atmospheric pressure. For a wing loading of 50 pounds per square foot the cruising altitude would be 60,000 feet and the indicated airspeed 290 miles per hour.
| Author | : Charles H. McLellan |
| Publisher | : |
| Total Pages | : 22 |
| Release | : 1956 |
| Genre | : Aerodynamics, Supersonic |
| ISBN | : |
A study of the factors affecting the maximum lift-drag ratio has been conducted in an effort to determine how to obtain high aerodynamic values at high supersonic Mach numbers.
