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Wind tunnel pressure distribution tests on a series of biplane wing models Part III : effects of charges in various combinations of stagger, gap, sweepback, and decalage
A concept for the calculation of the vortex lift of sharp-edge delta wings is presented and compared with experimental data. The concept is based on an analogy between the vortex lift and the leading-edge suction associated with the potential flow about the leading edge. This concept, when combined with potential-flow theory modified to include the nonlinearities associated with the exact boundary condition and the loss of the lift component of the leading-edge suction, provides excellent prediction of the total lift for a wide range of delta wings up to angles of attack of 20 degrees or greater. digital.library.unt.edu/ark:/67531/metadc54019/
Wind tunnel pressure distribution tests on an airfoil with trailing edge flap
This report deals with pressure distribution tests on an airfoil with a conventional trailing edge flap. These tests were conducted in the Atmospheric Wind Tunnel of the National Advisory Committee for Aeronautics. Maximum chord loadings were obtained with the flap displaced downward and with the airfoil at large angles of attack. Greater changes were produced in the normal force and in the center of pressure travel by up-flap than by an equal down-flap displacement. digital.library.unt.edu/ark:/67531/metadc53999/
Wind-tunnel research comparing lateral control devices, particularly at high angles of attack IX : tapered wings with ordinary ailerons
Tests were made with ordinary flap-type ailerons on two wings with different amounts of taper, one medium and the other extreme. On each wing both medium sized tapered ailerons and short wide tapered ailerons were tested. digital.library.unt.edu/ark:/67531/metadc54124/
Wind tunnel research comparing lateral control devices, particularly at high angles of attack VIII : straight and skewed ailerons on wings with rounded tips
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. digital.library.unt.edu/ark:/67531/metadc54107/
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
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. digital.library.unt.edu/ark:/67531/metadc54129/
Wind tunnel research comparing lateral control devices, particularly at high angles of attack XI : various floating tip ailerons on both rectangular and tapered wings
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. digital.library.unt.edu/ark:/67531/metadc54199/
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
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. digital.library.unt.edu/ark:/67531/metadc54096/
Wind tunnel standardization disk drag
No Description digital.library.unt.edu/ark:/67531/metadc59653/
Wind-tunnel studies of the performance of multirotor configurations
No Description digital.library.unt.edu/ark:/67531/metadc57078/
Wind-tunnel technique for simultaneous simulation of external flow field about nacelle inlet and exit airstreams at supersonic speeds
No Description digital.library.unt.edu/ark:/67531/metadc56364/
Wind-tunnel tests and analysis of two 10-foot-diameter six-blade dual-rotating tractor propeller differing in pitch distribution
No Description digital.library.unt.edu/ark:/67531/metadc54728/
Wind-tunnel tests at low speed of swept and yawed wings having various plan forms
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. digital.library.unt.edu/ark:/67531/metadc55724/
Wind-tunnel tests of a 2-engine airplane model as a preliminary study of flight conditions arising on the failure of the engine
Wind tunnel tests of a 15-foot-span model of a two-engine low wing transport airplane were made as a preliminary study of the emergency arising from the failure of one engine in flight. Two methods of reducing the initial yawing moment resulting from the failure of one engine were investigated and the equilibrium conditions were explored for two basic modes on one engine, one with zero angle of sideslip and the other with several degrees of sideslip. The added drag resulting from the unsymmetrical attitudes required for flight on one engine was determined for the model airplane. The effects of the application of power upon the stability, controllability, lift, and drag of the model airplane were measured. A dynamic pressure survey of the propeller slipstream was made in the neighborhood of the tail surfaces at three angles of attack. The added parasite drag of the model airplane resulting from the unfavorable conditions of flight on one engine was estimated. From 35 to 50 percent of this added drag was due to the drag of the dead engine propeller and the other 50 to 65 percent was due to the unsymmetrical attitude of the airplane. The mode of flight on one engine in which the angle of sideslip was zero was found to require less power than the mode in which the angle of sideslip was several degrees. digital.library.unt.edu/ark:/67531/metadc54358/
Wind-tunnel tests of a Clark Y wing having split flaps with gaps
Tests were made of the Clark Y wing having split flaps with a gap between the flap and the lower surface of the wing. Lift, drag, and pitching moments were measured for the wing with three different sizes of flap. It was found that any gap between the flap and the wing reduced the lift, the drag, and the pitching moments, but that the center-of-pressure movement and the ratio of lift to drag were little affected. digital.library.unt.edu/ark:/67531/metadc54384/
Wind-tunnel tests of a Clark Y wing with 'Maxwell' leading-edge slots
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. digital.library.unt.edu/ark:/67531/metadc54243/
Wind-tunnel tests of a cyclogiro rotor
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. digital.library.unt.edu/ark:/67531/metadc54157/
Wind-tunnel tests of a full-scale helicopter rotor with symmetrical and with cambered blade sections at advance ratios from 0.3 to 0.4
No Description digital.library.unt.edu/ark:/67531/metadc57455/
Wind-tunnel tests of a Hall high-life wing
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. digital.library.unt.edu/ark:/67531/metadc54101/
Wind-tunnel tests of a wing with a trailing-edge auxiliary airfoil used as a flap
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. digital.library.unt.edu/ark:/67531/metadc56466/
Wind tunnel tests of an NACA 23021 airfoil equipped with a slotted extensible and a plain extensible flap
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. digital.library.unt.edu/ark:/67531/metadc54616/
Wind-tunnel tests of carburetor-intake rams
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. digital.library.unt.edu/ark:/67531/metadc54440/
Wind tunnel tests of five strut sections in yaw
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. digital.library.unt.edu/ark:/67531/metadc53818/
Wind tunnel tests of fuselages and windshields
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. digital.library.unt.edu/ark:/67531/metadc53879/
Wind-tunnel tests of several forms of fixed wing slot in combination with a slotted flap on an N.A.C.A. 23012 airfoil
No Description digital.library.unt.edu/ark:/67531/metadc54404/
Wind-tunnel tests of the Fowler variable-area wing
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. digital.library.unt.edu/ark:/67531/metadc54106/
Wind-tunnel tests of wing flaps suitable for direct control of glide-path angle
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. digital.library.unt.edu/ark:/67531/metadc54259/
Wind tunnel tests on a model of a monoplane wing with floating ailerons
This report describes preliminary wind tunnel tests on a model of a monoplane wing equipped with wing tip floating ailerons. Lift and drag, as well as rolling and yawing moments, were measured. digital.library.unt.edu/ark:/67531/metadc54036/
Wind tunnel tests on airfoil boundary control using a backward opening slot
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. digital.library.unt.edu/ark:/67531/metadc53977/
Wind tunnel tests on an airfoil equipped with a split flap and a slot
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. digital.library.unt.edu/ark:/67531/metadc53979/
Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot
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. digital.library.unt.edu/ark:/67531/metadc56527/
Wing-body combinations with certain geometric restraints having low zero-lift wave drag at low supersonic Mach numbers
No Description digital.library.unt.edu/ark:/67531/metadc56711/
Wing-body interference at supersonic speeds with an application to combinations with rectangular wings
No Description digital.library.unt.edu/ark:/67531/metadc56991/
Wing plan forms for high-speed flight
No Description digital.library.unt.edu/ark:/67531/metadc55311/
Wing pressure-distribution measurements up to 0.866 Mach number in flight on a jet-propelled airplane
No Description digital.library.unt.edu/ark:/67531/metadc55313/
Wing-tunnel investigation of effects of forward movements of transition on section characteristics of a low-drag airfoil with a 0.24-chord sealed plain aileron
No Description digital.library.unt.edu/ark:/67531/metadc55768/
Wing-tunnel investigation of effects of various aerodynamic balance shapes and sweepback on control-surface characteristics of semispan tail surfaces with NACA 0009, 0015, 66-009, 66(215)-014, and circular-arc airfoil sections
No Description digital.library.unt.edu/ark:/67531/metadc55844/
Working charts for the stress analysis of elliptic rings
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. digital.library.unt.edu/ark:/67531/metadc54100/
X-ray diffraction by bent crystal lamellae
No Description digital.library.unt.edu/ark:/67531/metadc55904/
X-ray diffraction investigation of minor phases of 20 high-temperature alloys
No Description digital.library.unt.edu/ark:/67531/metadc54566/
X-Ray Diffraction Study of the Internal Structure of Supercooled Water
A Bragg X-ray spectrometer equipped with a volume-sensitive Geiger counter and Soller slits and employing filtered molybdenum Ka radiation was used to obtain a set of diffracted intensity curves as a Punction of angle for supercooled water. Diffracted intensity curves in the temperature region of 21 to -16 C were obtained. The minimum between the two main diffraction peaks deepened continuously with lowering temperature, indicating a gradual change in the internal structure of the water. No discontinuity in this trend was noted at the melting point. The internal structure of supercooled water was concluded to become progressively more ice-like as the temperature is lowered. digital.library.unt.edu/ark:/67531/metadc53469/
X-ray instrumentation for density measurements in a supersonic flow field
No Description digital.library.unt.edu/ark:/67531/metadc56587/
The zero-lift drag of a 60 degree delta-wing-body combination (AGARD model 2) obtained from free-flight tests between Mach numbers of 0.8 and 1.7
No Description digital.library.unt.edu/ark:/67531/metadc56898/
The zero-lift drag of a slender body of revolution (NACA RM-10 research model) as determined from tests in several wind tunnels and in flight at supersonic speeds
Presents zero-lift drag data of an NACA RM-10 slender body of revolution with and without stabilizing fins attached. The results from several wind tunnels and in flight are compared. The results cover a Reynolds number range from about 1 time 10 to the 6th power to 40 times 10 to the 6th power for the flight models. The Mach numbers covered include 1.5 to 2.4 in the wind tunnels and 0.85 to 2.5 in flight. digital.library.unt.edu/ark:/67531/metadc56732/
The zero-lift wave drag of a particular family of unswept, tapered wings with linearly varying thickness ratio
No Description digital.library.unt.edu/ark:/67531/metadc57644/
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