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Wind-tunnel research comparing lateral control devices, particularly at high angles of attack VI : skewed ailerons on rectangular wings

Description: This report covers the sixth of a series of investigations in which various lateral control devices are compared with particular reference to their effectiveness at high angles of attack. The present report deals with flap-type ailerons hinged about axes having an angle with respect to the leading and trailing edges of the wing. Tests were made on four different skewed ailerons, including two different angles of skew and two sizes of ailerons. At the high angles of attack, all the skewed ailerons tested were slightly inferior with respect to rolling and yawing moments to straight ailerons having the same span and average chord. Computations indicate that the skewed ailerons are also inferior with respect to hinge moments.
Date: January 1, 1934
Creator: Weick, Fred E. & Harris, Thomas A.

Wind tunnel research comparing lateral control devices, particularly at high angles of attack VIII : straight and skewed ailerons on wings with rounded tips

Description: Tests showed the effect of the ailerons and the tip shapes on the general performance of the wing, as well as on the lateral control and stability characteristics. The hinge moments were not measured but the approximate values are given in the first report of the series.
Date: February 1, 1933
Creator: Weick, Fred E. & Shortal, Joseph A.

Wind tunnel research comparing lateral control devices, particularly at high angles of attack X : various control devices on a wing with a fixed auxiliary airfoil

Description: Results are given of a series of systemic tests comparing lateral control devices with particular reference to their effectiveness at high angles of attack. These tests were made with two sizes of ordinary ailerons and different sizes of spoilers on a Clark Y wing model having a narrow auxiliary airfoil fixed ahead and above the leading edge, the chords of the main and auxiliary airfoils being parallel. In addition, the auxiliary airfoil itself was given angular deflection. The purpose was to provide rolling moments for lateral control. The tests were made in a 7 by 10 foot wind tunnel. They included both force and rotation tests to show the effect of the devices on the lift and drag characteristics of the wing and on the lateral stability characteristics, as well as lateral control. They showed that none of the aileron arrangements tried would give rolling control of an assumed satisfactory value at all angles of attack up to the stall. However, they would give satisfactory values, but at the expense of abnormally high deflections and very heavy hinge moments. The most effective combination of ailerons and spoilers gave satisfactory values of rolling moment at angles of attack below the stall, and the values did not fall off as rapidly above the stall as with ailerons alone. With an arrangement of this type having the proper relative proportions and linkage, it should be possible to obtain reasonably satisfactory yawing moments and control forces. Deflecting one-half of the auxiliary airfoil downward for the purpose of control gave strong favorable yawing moments at all angles of attack, but gave very small rolling moments at the low angles of attack.
Date: March 1, 1933
Creator: Weick, Fred E. & Noyes, Richard W.

Wind tunnel research comparing lateral control devices, particularly at high angles of attack XI : various floating tip ailerons on both rectangular and tapered wings

Description: Discussed here are a series of systematic tests being conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present tests were made with six different forms of floating tip ailerons of symmetrical section. The tests showed the effect of the various ailerons on the general performance characteristics of the wing, and on the lateral controllability and stability characteristics. In addition, the hinge moments were measured for the most interesting cases. The results are compared with those for a rectangular wing with ordinary ailerons and also with those for a rectangular wing having full-chord floating tip ailerons. Practically all the floating tip ailerons gave satisfactory rolling moments at all angles of attack and at the same time gave no adverse yawing moments of appreciable magnitude. The general performance characteristics with the floating tip ailerons, however, were relatively poor, especially the rate of climb. None of the floating tip ailerons entirely eliminated the auto rotational moments at angles of attack above the stall, but all of them gave lower moments than a plain wing. Some of the floating ailerons fluttered if given sufficiently large deflection, but this could have been eliminated by moving the hinge axis of the ailerons forward. Considering all points including hinge moments, the floating tip ailerons on the wing with 5:1 taper are probably the best of those which were tested.
Date: May 1, 1933
Creator: Weick, Fred E. & Harris, Thomas A.

Wind-tunnel research comparing lateral control devices, particularly at high angles of attack XII : upper-surface ailerons on wings with split flaps

Description: This report covers the twelfth of a series of tests conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made with two sizes of upper-surface ailerons on rectangular Clark Y wing models equipped with full span split flaps. The tests showed the effect of the upper-surface ailerons and of the split flaps on the general performance characteristics of the wings, and on the lateral controllability and stability characteristics. The results are compared with those for plain wings with ordinary ailerons of similar sizes.
Date: January 1, 1935
Creator: Weick, Fred E. & Wenzinger, Carl J.

Wind-tunnel research comparing lateral control devices particularly at high angles of attack XIII : auxiliary airfoils used as external ailerons

Description: This is the thirteenth report on a series of systematic tests comparing lateral control devices with particular reference to their effectiveness at high angles of attack. The present wind tunnel tests were made to determine the most feasible locations for lateral control surfaces mounted externally to a rectangular Clark y wing.
Date: January 1, 1936
Creator: Weick, Fred E. & Noyes, Richard W.

Wind tunnel research concerning lateral control devices, particularly at high angles of attack VII : Handley Page tip and full-span slots with ailerons and spoilers

Description: Tests were made with ordinary ailerons and different sizes of spoilers on rectangular Clark Y wing models with Handley Page tip and full span slots. The tests showed the effect of the control devices on the general performance of the wings as well as on the lateral control and lateral stability characteristics.
Date: January 1, 1933
Creator: Weick, Fred E. & Wenzinger, Carl J.

Wind tunnel studies in aerodynamic phenomena at high speed

Description: A great amount of research and experimental work has been done and fair success obtained in an effort to place airplane and propeller design upon an empirical basis. However, one can not fail to be impressed by the apparent lack of data available toward establishing flow phenomena upon a rational basis, such that they may be interpreted in terms of the laws of physics. With this end in view it was the object of the authors to design a wind tunnel differing from the usual type especially in regard to large power and speed of flow. This report describes the wind tunnel at Mccook Field and gives the results of experiments conducted in testing the efficiency of the wind tunnel.
Date: January 1, 1921
Creator: Caldwell, F W & Fales, E N

A wind-tunnel test technique for measuring the dynamic rotary stability derivatives at subsonic and supersonic speeds

Description: A method is described for measuring the dynamic stability derivatives of a model airplane in a wind tunnel. The characteristic features of this system are that single-degree-of-freedom oscillations were used to obtain combinations of rolling, yawing and pitching motions; that the oscillations were excited and controlled by velocity feedback which permitted operation under conditions unfavorable for more conventional types of oscillatory testing; and that data processing was greatly simplified by using analog computer elements in the strain-gage circuitry. A small number of experimental data are included to illustrate the general scope of results obtainable with this system.
Date: January 1, 1956
Creator: Beam, Benjamin H

Wind-tunnel tests and analysis of three 10-foot-diameter three-blade tractor propellers differing in pitch distribution

Description: Report discussing an investigation of the effect of variations in pitch distribution on propeller efficiency at low Mach numbers. The three 10-foot-diameter propellers tested consisted of three blades mounted on a streamline body and were tested for a blade-angle range from 15 degrees to 60 degrees. Information about the propeller thrust, power coefficients, force-balance measurements, and total pressure in the propeller wake is provided.
Date: August 1946
Creator: Gilman, Jean, Jr.

Wind-tunnel tests at low speed of swept and yawed wings having various plan forms

Description: Results are presented of wind-tunnel tests made at low speed of various small-scale models of sweptback, sweptforward, and yawed wings. The tests covered changes in aspect ratio, taper ratio, and tip shape. Some data were obtained with high-lift devices on sweptback wings and with ailerons on sweptforward wings. The data have been briefly analyzed and some comparisons have been made with the available theory.
Date: December 1, 1951
Creator: Purser, Paul E. & Spearman, M. Leroy

Wind-tunnel tests of 10-foot-diameter autogiro rotors

Description: Report presents the results of a series of 10-foot-diameter autogiro rotor models tested in the NACA 20-foot wind tunnel. Four of the models differed only in the airfoil sections of the blades, the sections used being the NACA 0012, 0018, 4412, and 4418. Three additional models employing the NACA 0012 section were tested, in which a varying portion of the blade near the hub was replaced by a streamline tube with a chord of about one-fourth the blade chord.
Date: January 1, 1937
Creator: Wheatley, John B & Bioletti, Carlton

Wind-Tunnel Tests of a 0.16-Scale Model of the Douglas MX-656 Airplane at High Subsonic Speeds, 1, Stability and Control Characteristics

Description: Wind tunnel tests of the 0.16-scale Douglas MX-656 model were made at low and high subsonic Mach numbers to investigate the static longitudinal- and lateral stability characteristics. The tests shows that undesirable changes in longitudinal stability at the stall were apparently caused by an altered downwash pattern at the tail. The jettisonable nose fins were highly destabilizing. Compressibility effects for the test Mach numbers were not detrimental to the longitudinal- or lateral-stability characteristics.
Date: April 1, 1949
Creator: Hamilton, William T. & Cleary, Joseph W.

Wind-Tunnel Tests of a 0.16-Scale Model of the Douglas MX-656 Airplane at High Subsonic Speeds. II - Wing and Fuselage Pressure Distribution

Description: Measurements of wing and fuselage pressure distributions were made at low and high subsonic Much numbers on a 0.16-scale model of the projected MX-656 research airplane. The MX-656 is a supersonic design utilizing a low-aspect-ratio wing and tail. Pressure-distribution measurements indicated that, although the critical Mach number of the wing was approximately 0.81 at 0 degree angle of attack, compressibility effects were of little significance below a Mach number of at least 0.90. The principal effect of compressibility was an increase in the pressure gradient over the after 30 percent of the wing chord, causing a tendency for the flow to separate. At 0.40 Mach number, the wing stalled abruptly at approximately 12 deg, angle of attack. The wing-pressure distribution showed this stall was a result of complete separation of the flow from the upper surface of the wing, Deflecting the leading-edge flaps delayed the stall to a higher angle of attack with some increase in the maximum section normal force,.
Date: August 22, 1949
Creator: Cleary, Joseph W. & Mellenthin, Jack A.