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Wind-tunnel tests of a Clark Y wing with 'Maxwell' leading-edge slots

Description: Aerodynamic force tests of a Clark Y wing equipped with "Maxwell" type leading-edge slots were conducted in the N.A.C.A. 7- by 10-foot tunnel to ascertain the aerodynamic characteristics, which involved the determination of the best slot-gap opening, the effects of slat width, and the effect of a trailing-edge flap. The Maxwell wing with a wide-chord slat (0.30 c(sub w)) and with a 0.211 c(sub w) split flap deflected 60 degrees had a C(sub L sub max) of 2.53 or about twice that of the plain wing. The wing with the wide slat also had, in general, improved aerodynamic characteristics over those of the Maxwell wing with slat, and had about the same aerodynamic characteristics as a Handley Page slotted wing with approximately the same size of slat.
Date: April 1, 1937
Creator: Gauvain, William E

Wind-tunnel tests of a cyclogiro rotor

Description: During an extensive study of all types of rotating wings, the NACA examined the cyclogiro rotor and made an aerodynamic analysis of that system (reference 1). The examination disclosed that such a machine had sufficient promise to justify an experimental investigation; a model with a diameter and span of 8 feet was therefore constructed and tested in the 20-foot wind tunnel during 1934. The experimental work included tests of the effect of the motion upon the rotor forces during the static-lift and forward-flight conditions at several rotor speeds and the determination of the relations between the forces generated by the rotor and the power required by it.
Date: May 1, 1935
Creator: Wheatley, John B & Windler, Ray

Wind-tunnel tests of a Hall high-life wing

Description: Wind-tunnel tests have been made to find the lift, drag, and center-of-pressure characteristics of a Hall high-lift wing model. The Hall wing is essentially a split-flap airfoil with an internal air passage. Air enters the passage through an opening in the lower surface somewhat back of and parallel to the leading edge, and flows out through an opening made by deflecting the rear portion of the under surface downward as a flap. For ordinary flight conditions the front opening and the rear flap can be closed, providing in effect a conventional airfoil (the Clark Y in this case). The tests were made with various flap settings and with the entrance to the passage both open and closed. The highest lift coefficient found, C(sub L) = 2.08, was obtained with the passage closed.
Date: May 1, 1932
Creator: Weick, Fred E. & Sanders, Robert

Wind-tunnel tests of a wing with a trailing-edge auxiliary airfoil used as a flap

Description: This report gives the characteristics of a wing with an auxiliary airfoil mounted near its trailing edge and used as a flap. The tests were made with a 10 by 60 inch Clark Y main airfoil and an NACA 0012 flap having a chord equal to 15 percent of the main wing chord. The axis of the flap in all cases was on the flap chord and 20 percent back from its leading edge. The optimum location of the flap axis relative to the main wing for maximum lift was found to be 1.25 percent of the main wing chord behind the trailing edge and 2.5 percent below the chord. In this position C(sub L max) was increased from 1.250 (for the plain wing) to 1.810 at 45 degrees deflection of the flap and C(sub D min) was decreased form 0.0155 to 0.0146 at minus 5 degrees deflection, the coefficient in each case being based on the sum of the flap and wing areas. No serious adverse change in lateral stability was found to result from the use of the flap in the optimum position.
Date: January 1, 1935
Creator: Noyes, Richard W

Wind tunnel tests of an NACA 23021 airfoil equipped with a slotted extensible and a plain extensible flap

Description: An investigation has been made in the NACA 7- by 10-foot wind tunnel of a large chord NACA 23021 airfoil equipped with two arrangements of a completely extended 15 percent chord extensible flap. One of the flaps had a faired juncture, without a gap; the other was provided with a slot between the trailing edge of the airfoil and the nose of the flap. The results showed that the basic airfoil gave the lowest profile-drag coefficients over the low lift range, the airfoil with the plain extensible flap gave the lowest profile-drag coefficients over the moderate lift range, and the airfoil with the slotted extensible flap gave the lowest profile-drag coefficients over the high lift range. The airfoil with the slotted extensible flap had the same maximum lift at a flap deflection of 25 degrees as the airfoil with the plain extensible flap had at a flap deflection of 60 degrees. The results of comparisons of the airfoil pitching-moment coefficients obtained with the two types of flap are dependent upon the basis chosen for comparison. Complete aerodynamic section characteristics are presented for the various flap deflections for both flap arrangements in the completely extended portion.
Date: November 1, 1940
Creator: Swanson, Robert S & Harris, Thomas A

Wind-tunnel tests of carburetor-intake rams

Description: An investigation was conducted in the NACA 20-foot wind tunnel of the ramming effect of three general types of carburetor intake rams for radial engines, namely, the internal constant area type, the external constant area type, and the external expanding type. The rams were installed on a radial air- cooled engine nacelle, and tests were made with and without the propeller operating. The results indicated that the external types having entrances near the front of the engine cowling gave the greatest ramming effect. The propeller increased the ramming effect for the external types. From considerations of the ramming effect, the best entrance location for the external types was close to the nose of the engine cowling. For the internal type, the best location was in a plane perpendicular to the propeller shaft and immediately forward of the engine cylinders.
Date: January 1, 1938
Creator: Highley, Frank H

Wind tunnel tests of five strut sections in yaw

Description: In the first series of wind tunnel tests, the drag and cross wing force of all the struts were measured at a wind speed of 30 mph and at angles of yaw from 0 degrees to 20 degrees. To determine the magnitude of the VL effect, each strut was tested at zero yaw and at a series of speeds ranging from 15 to 38 mph. Although designed as fairings for cables, part of these sections gave such high crosswind forces that they seemed to have possibilities as airfoils. Therefore, the lift (identical with the crosswind force) and drag coefficients were recalculated for four sections on the basis of broadside area to make them comparable with wing coefficients. The general conclusion that the best fineness ratio for a strut is a function of the Reynolds number, decreasing steadily as that quality increases, has of course been reached many times, both by theory and experiment. It was confirmed here once more, and the effect of form on sensitiveness to VL is also strikingly shown. It seems probable that this effect of form is largely due to interaction between the nose and tail, and to the influence which the form of the nose exerts over the whole flow around the strut.
Date: November 1, 1923
Creator: Warner, Edward P.

Wind tunnel tests of fuselages and windshields

Description: The tests described herein were made in 1918, in the old four-foot wind tunnel at the Massachusetts Institute of Technology and at the request of the Engineering Division of the U.S. Army Air Service. The results were given circulation only in official circles at that time. The interest of the work appears sufficient to justify its wider distribution even at this very late date.
Date: September 1, 1925
Creator: Warner, Edward P.

Wind-tunnel tests of the Fowler variable-area wing

Description: The lift, drag, and center of pressure characteristics of a model of the Fowler variable-area wing were measured in the NACA 7 by 10 foot wind tunnel. The Fowler wing consists of a combination of a main wing and an extension surface, also of airfoil section. The extension surface can be entirely retracted within the lower rear portion of the main wing or it can be moved to the rear and downward. The tests were made with the nose of the extension airfoil in various positions near the trailing edge of the main wing and with the surface at various angular deflections. The highest lift coefficient obtained was C(sub L) = 3.17 as compared with 1.27 for the main wing alone.
Date: May 1, 1932
Creator: Weick, Fred E. & Platt, Robert C.

Wind-tunnel tests of wing flaps suitable for direct control of glide-path angle

Description: Preliminary tests have been made for the purpose of obtaining a flap arrangement suitable for direct and immediate control of the steepness of the glide path of an airplane, a use for which present flaps are not satisfactory. An attempt has been made to develop a flap giving a reasonably high maximum lift coefficient with relatively low deflection and maintaining this value of the maximum lift coefficient with a large increase of deflection, the increase in deflection being accompanied by a large increase in drag. An arrangement was found that gave a maximum lift coefficient of approximately 1.90 for all flap deflections between 25 and 80 degrees, within which range the drag of the wing increased regularly to a large value.
Date: January 1, 1936
Creator: Weick, Fred E.

Wind tunnel tests on airfoil boundary control using a backward opening slot

Description: This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil equipped with a backward opening slot. Various slot locations, widths of opening, and pressures, were used. The tests were conducted in the Five-Foot Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The greatest increase in maximum lift was 96 per cent, the greatest decrease in minimum drag was 27 per cent, and the greatest increase in the ratio, maximum lift coefficient/minimum drag coefficient, was 151 per cent.
Date: October 1, 1929
Creator: Knight, Montgomery & Bamber, Millard J

Wind tunnel tests on an airfoil equipped with a split flap and a slot

Description: The investigation described in this report is concerned with the changes in the aerodynamic characteristics of an airfoil which are produced by a gauze-covered suction slot, located near the leading edge, and connected by an air passage to a split flap at the trailing edge. The tests were conducted at the Langley Memorial Aeronautical Laboratory. At the larger values of lift coefficient where the action of the slot might be expected to be most effective, the pressure differences were such that the air flowed out of the slot rather than in through it, and in consequence, the maximum lift coefficient was decreased.
Date: October 1, 1929
Creator: Bamber, Millard J

Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot

Description: An investigation was made in the NACA 7 by 10 foot wind tunnel to find the increase in maximum lift coefficient which could be obtained by providing a model wing with both a Fowler trailing-edge extension flap and a Handley Page type leading-edge slot. A conventional Handley page slot proportioned to operate on the plain wing without a flap gave but a slight increase with the flap; so a special form of slot was developed to work more effectively with the flap. With the best combined arrangement the maximum lift coefficient based on the original area was increased from 3.17, for the Fowler wing, to 3.62. The minimum drag coefficient with both devices retracted was increased in approximately the same proportion. Tests were also made with the special-type slot on the plain wing without the flap. The special slot, used either with or without the Fowler flap, gave definitely higher values of the maximum lift coefficient than the slots of conventional form, with an increase of the same order in the minimum drag coefficient.
Date: May 1, 1933
Creator: Weick, Fred E. & Platt, Robert C.

Working charts for the stress analysis of elliptic rings

Description: This report presents charts which reduce the stress analysis of circular and elliptic rings of uniform cross section subjected to balanced systems of concentrated loads from a statically indeterminate problem to a statically determinate one. To demonstrate the use of the charts in the stress analysis of elliptic rings, an illustrative problem is included.
Date: January 1, 1933
Creator: Burke, Walter F