Estimated Lift Drag Ratios At Supersonic Speed
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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.
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 | : 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 | : 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 | : Edwin J. Saltzman |
Publisher | : |
Total Pages | : 60 |
Release | : 1966 |
Genre | : Aerodynamics, Supersonic |
ISBN | : |
Author | : A.J. Jr Eggers |
Publisher | : |
Total Pages | : 36 |
Release | : 1956 |
Genre | : |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 28 |
Release | : 1966 |
Genre | : |
ISBN | : |
Author | : Edward J. Hopkins |
Publisher | : |
Total Pages | : 22 |
Release | : 1962 |
Genre | : Drag (Aerodynamics) |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 80 |
Release | : 1960 |
Genre | : Aerodynamics, Supersonic |
ISBN | : |
A free-flight rocket-propelled-model investigation was conducted at Mach numbers of 1.2 to 1.9 to determine the longitudinal and lateral aero-dynamic characteristics of a low-drag aircraft configuration. The model consisted of an aspect-ratio -1.86 arrow wing with 67.5 deg. leading-edge sweep and NACA 65A004 airfoil section and a triangular vertical tail with 60 deg. sweep and NACA 65A003 section in combination with a body of fineness ratio 20. Aerodynamic data in pitch, yaw, and roll were obtained from transient motions induced by small pulse rockets firing at intervals in the pitch and yaw directions. From the results of this brief aerodynamic investigation, it is observed that very slender body shapes can provide increased volumetric capacity with little or no increase in zero-lift drag and that body fineness ratios of the order of 20 should be considered in the design of long-range supersonic aircraft. The zero-lift drag and the drag-due-to-lift parameter of the test configuration varied linearly with Mach number. The maximum lift-drag ratio was 7.0 at a Mach number of 1.25 and decreased slightly to a value of 6.6 at a Mach number of 1.81. The optimum lift coefficient, normal-force-curve slope, lateral-force-curve slope, static stability in pitch and yaw, time to damp to one-half amplitude in pitch and yaw, the sum of the rotary damping derivatives in pitch and also in yaw, and the static rolling derivatives all decreased with an increase in Mach number. Values of certain rolling derivatives were obtained by application of the least-squares method to the differential equation of rolling motion. A comparison of the experimental and calculated total rolling-moment-coefficient variation during transient oscillations of the model indicated good agreement when the damping-in-roll contribution was included with the static rolling-moment terms.