An Investigation of a Lifting 10-Percent-Thick Symmetrical Double-Wedge Airfoil at Mach Numbers Up to 1

An Investigation of a Lifting 10-Percent-Thick Symmetrical Double-Wedge Airfoil at Mach Numbers Up to 1
Author:
Publisher:
Total Pages: 0
Release: 1954
Genre:
ISBN:

Pressure measurements on the surface of a two-dimensional symmetrical double-wedge airfoil have been obtained from tests in the Langley 4- by 19-inch semiopen tunnel at lifting conditions and at Mach numbers up to 1. The object of this investigation was to obtain normal-force, pressure-drag, and pitching-moment data and to compare them with available experimental and theoretical results. The nonlifting results are in good agreement with potential-flow theory at a Mach number of about 0.5 and in fair agreement with the theoretical results of Guderley and Yoshihara at a Mach number of 1 and with the transonic small-disturbance theories of other investigators for Mach numbers from 0.85 to 1.0. Below a reduced Mach number Xio of approximately -1.0, the pressure-drag coefficient computed on the basis of the transonic theories and the drag coefficient measured in the present investigation are of opposite sign. The present experimental data and the theoretical incompressible results extended to high-subsonic speeds both indicate a thrust for the forebody. The application of transonic approximations, therefore, appears unjustified for similarity parameters less than approximately -1.0 in the subsonic portion of the transonic range. At lifting conditions, for Mach numbers up to about 0.6, the present results are in good agreement with the closed-tunnel data of Bartlett and Peterson and with low-speed theoretical data extended to a Mach number of 0.6.

Experimental Investigation of the Flow Around Lifting Symmetrical Double-wedge Airfoils at Mach Numbers of 1.30 and 1.41

Experimental Investigation of the Flow Around Lifting Symmetrical Double-wedge Airfoils at Mach Numbers of 1.30 and 1.41
Author: Paul B. Gooderum
Publisher:
Total Pages: 86
Release: 1956
Genre: Aerofoils
ISBN:

Measurements were made of the flow around a 10-percent-thick, double symmetrical, two-dimensional wedge at a Mach number of 1.30 and of a 14.2-percent-thick wedge at Mach numbers of 1.30 and 1.41 for various angles of attack up to 5 degrees. Results were thus obtained in the vicinity of the theoretically interesting region between shock attachment and the lower limit for completely supersonic flow over the surface of the airfoil. Pressure and Mach number distributions, lift and drag coefficients, center of lift, and pitching moment are presented for the angles of attack used. By means of the transonic similarity laws, the results are compared with each other, with small-disturbance theory, and with shock-expansion theory wherever possible. The data show that pressure distributions on wedges of different thickness and Mach number are similar at the same values of transonic similarity parameter and reduced angle of attack for angles of attack as large as the thickness ratio; that the lift-curve slope is approximately independent of the angle of attack for an angle-of-attack range from -2 degrees to 2 degrees; and that, for the airfoils tested at Mach numbers greater than the attachment value, the center-of-pressure location is nearly independent of the angle of attack, the variation being to plus or minus 3 percent chord for the angles of attack used in this investigation. For the airfoil tested at a Mach number slightly less than the shock-attachment value, the center-of-pressure location was only roughly independent of the angle of attack, the variation of this location being to plus or minus 6 percent chord.

Qualitative Simulator Study of Longitudinal Stick Forces and Displacements Desirable During Tracking

Qualitative Simulator Study of Longitudinal Stick Forces and Displacements Desirable During Tracking
Author: Stanley Faber
Publisher:
Total Pages: 680
Release: 1958
Genre: Airplanes
ISBN:

In this study in which an airplane simulator with one degree of freedom (pitch) was used, results were determined for three conditions of airplane dynamics. For an undamped natural frequency of 1/2 cps with a damping ratio of 0.18 and for an undamped natural frequency of 1 cps with a damping ratio of 0.11, moderate longitudinal stick forces and displacements were desired.

Research Abstracts

Research Abstracts
Author: United States. National Advisory Committee for Aeronautics
Publisher:
Total Pages: 568
Release: 1951
Genre: Aeronautics
ISBN: