National Advisory Committee for Aeronautics (NACA) - 127 Matching Results

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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
Partner: UNT Libraries Government Documents Department

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
Partner: UNT Libraries Government Documents Department

The use of wheel brakes on airplanes

Description: The results of tests to determine the effect of wheel brakes on the landing run of an airplane under conditions of load and at various wind velocities are presented.
Date: July 1, 1929
Creator: Carroll, Thomas & Defrance, Smith J
Partner: UNT Libraries Government Documents Department

The formation of ice upon airplanes in flight

Description: This report describes the atmospheric conditions under which ice is formed upon the exposed parts of airplanes in flight. It identifies the formation found under different conditions, and describes some studies of preventative means.
Date: August 1, 1929
Creator: Carroll, Thomas & Mcavoy, William H
Partner: UNT Libraries Government Documents Department

Wind tunnel pressure distribution tests on a series of biplane wing models

Description: This report is on the changes in forces on each wing of a biplane cellule when either the stagger or the gap is varied. Since each test was carried up to a 90 degree angle of attack, the results may be used in the study of stalled flight and of spinning as well as in the structural design of biplane wings.
Date: July 1, 1929
Creator: Knight, Montgomery & Noyes, Richard
Partner: UNT Libraries Government Documents Department

Wind tunnel pressure distribution tests on a series of biplane wing models Part II : effects of changes in decalage, dihedral, sweepback and overhang

Description: This preliminary report furnishes information on the changes in the forces on each wing of a biplane cellule when the decalage, dihedral, sweepback and overhang are separately varied. The data were obtained from pressure distribution tests made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. Since each test was carried up to 90 degree angle of attack, the results may be used in the study of stalled flight and of spinning and in the structural design of biplane wings.
Date: October 1, 1929
Creator: Knight, Montgomery & Noyes, Richard W
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Date: December 1, 1929
Creator: Knight, Montgomery & Noyes, Richard W
Partner: UNT Libraries Government Documents Department

The effect of fuel consumption on cylinder temperatures and performance of a cowled Wright J-5 engine

Description: Given here are the results of tests made to determine the effect of fuel consumption on the cylinder temperatures and the performance of a cowled Wright J-5 engine. The results of these tests indicate that enriching the mixture by increasing the carburetor size results in a reduction in cylinder head and barrel temperatures. The cylinders shielded by the magnetos or the points on the cylinder that do not receive a free flow of cooling air increase most rapidly in temperature as the mixture is leaned. A free flow of air past the cylinders is essential for satisfactory operation on a lean mixture. The results of these tests show that the Wright J-5 engine can withstand severe temperatures for short periods of operation. The test results also show to what extent destructive temperatures may be avoided by enriching the mixture.
Date: November 1, 1929
Creator: Schey, Oscar W
Partner: UNT Libraries Government Documents Department

An investigation of the aerodynamic characteristics of an airplane equipped with several different sets of wings

Description: This investigation was conducted by the National Advisory Committee for Aeronautics at Langley Field, Va., at the request of the Army Air Corps, for the purpose of comparing the full scale lift and drag characteristics of an airplane equipped with several sets of wings of commonly used airfoil sections. A Sperry Messenger Airplane with wings of R.A.F.-15, U.S.A.-5, U.S.A.-27, and Gottingen 387 airfoil sections was flown and the lift and drag characteristics of the airplane with each set of wings were determined by means of glide tests. The results are presented in tabular and curve form. (author).
Date: January 1, 1929
Creator: Crowley, J W , Jr & Green, M W
Partner: UNT Libraries Government Documents Department

Some experiments on autorotation of an airfoil

Description: These experiments show that the rate of auto rotation of a monoplane airfoil is reduced by sweepback, ceasing entirely when the sweepback is 30 degrees. In addition a very serious increase in rate and range of auto rotation with yaw is shown.
Date: September 1, 1929
Creator: Ober, Shatswell
Partner: UNT Libraries Government Documents Department

Condensed data on the aircraft engines of the world

Description: This compilation of the outstanding characteristics of the available aircraft engines of the world was prepared as a compact ready reference for desk use. It does not pretend to be anything but a skeleton outline of the characteristics of engines reported in the technical press as being in either the experimental, development, or production stage.
Date: April 1, 1929
Creator: Fliedner, C S
Partner: UNT Libraries Government Documents Department

A new method for the prediction of airplane performance

Description: A new method for the prediction of airplane performance in level and climbing flight, together with complete information regarding propeller speeds, is described in this report. Developed from Bairstow's system and making use of American absolute coefficients, this method has advantages of simplicity and brevity.
Date: February 1, 1929
Creator: Lesley, E P & Reid, E G
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin VI : the effect of corrosion accompanied by stress on the tensile properties of sheet duralumin

Description: The effect of corrosion on the tensile properties of duralumin while stressed is shown in graphical form. According to the test results, duralumin sheet, coated with aluminum, maintains its initial properties unimpaired for corrosion periods as long as 60 days with an applied tensile stress as high as 20,000 lb/sq.in., which is approximately one-half the stress corresponding to the yield point as defined here. In these tests, that material which had been heat-treated by being quenched in cold water, though far inferior to similar material having the aluminum coating, was superior to the sheet material which was heat treated by being quenched in hot water. These results are in excellent agreement with the results of previous laboratory and exposure tests.
Date: May 1, 1929
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin V : results of weather-exposure tests

Description: In a series of weather exposure tests of sheet duralumin, upon which accelerated corrosion tests in the laboratory by the wet-and-dry corrosion method in a sodium chloride solution has already been carried out, a close parallelism between the results of the two kinds of tests was found to exist. The exposure tests showed that the lack of permanence of sheet duralumin is largely, if not entirely, due to corrosion. A corrosion attack of an intercrystalline nature is very largely responsible for the degree of embrittlement produced. The rate of embrittlement was greatly accelerated by a marine atmosphere and by the tropical climate. Variations in corrosion and embrittlement are noted in relation to heat treatment, cold working, and types of protective coatings.
Date: February 1, 1929
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department

Curves showing column strength of steel and duralumin tubing

Description: Given here are a set of column strength curves that are intended to simplify the method of determining the size of struts in an airplane structure when the load in the member is known. The curves will also simplify the checking of the strength of a strut if the size and length are known. With these curves, no computations are necessary, as in the case of the old-fashioned method of strut design. The process is so simple that draftsmen or others who are not entirely familiar with mechanics can check the strength of a strut without much danger of error.
Date: May 1, 1929
Creator: Ross, Orrin E
Partner: UNT Libraries Government Documents Department

A study of wing flutter

Description: Part I describes vibration tests, in a wind tunnel, of simple airfoils and of the tail plane of an M0-1 airplane model; it also describes the air flow about this model. From these tests are drawn inferences as to the cause and cure of aerodynamic wing vibrations. Part II derives stability criteria for wing vibrations in pitch and roll, and gives design rules to obviate instability. Part III shows how to design spars to flex equally under a given wing loading and thereby economically minimize the twisting in pitch that permits cumulative flutter. Resonant flutter is not likely to ensue from turbulence of air flow along past wings and tail planes in usual flying conditions. To be flutterproof a wing must be void of reversible autorotation and not have its centroid far aft of its pitching axis, i. e., axis of pitching motion. Danger of flutter is minimized by so proportioning the wing's torsional resisting moment to the air pitching moment at high-speed angles that the torsional flexure is always small. (author).
Date: January 1, 1929
Creator: Zahm, A F & Bear, R M
Partner: UNT Libraries Government Documents Department

Drag of C-class airship hulls of various fineness ratios

Description: This report presents the results of wind-tunnel tests on eight C-class airship hulls with various fineness ratios, conducted in the Navy Aerodynamic Laboratory, Washington. The purpose of the tests was to determine the variation of resistance with fineness ratio, and also to find the pressure and friction elements of the total drag for the model having the least shape coefficient. Seven C-class airship hulls with fineness ratios of 1.0, 1.5, 2.0, 3.0, 6.0, 8.0, and 10.0 were made and verified. These models and also the previously constructed original C-class hull, whose fineness ratio is 4.62, were then tested in the 8 by 8 foot tunnel for drag of 0 degree pitch and yaw, at various wind speeds. The original hull, which was found to have the least shape coefficient, was then tested for pressure distribution over the surface at various wind speeds. (author).
Date: January 1, 1929
Creator: Zahm, A F; Smith, R H & Louden, F A
Partner: UNT Libraries Government Documents Department

Theories of flow similitude

Description: The laws of comparison of dynamically similar fluid motions are derived by three different methods based on the same principle and yielding the same or equivalent formulas. This report outlines the three current methods of comparing dynamically similar motions, more especially of fluids, initiated respectively by Newton, Stokes (or Helmholtz), and Rayleigh. These three methods, viz., the integral, the differential, and the dimensional, are enough alike to be studied profitably together. They are treated in succession then compared. (author).
Date: January 1, 1929
Creator: Zahm, A F
Partner: UNT Libraries Government Documents Department

Forces on elliptic cylinders in uniform air stream

Description: This report presents the results of wind tunnel tests on four elliptic cylinders with various fineness ratios, conducted in the Navy Aerodynamic Laboratory, Washington. The object of the tests was to investigate the characteristics of sections suitable for streamline wire which normally has an elliptic section with a fineness ratio of 4.0; also to learn whether a reduction in fineness ratio would result in improvement; also to determine the pressure distribution on the model of fineness ratio of 4. Four elliptic cylinders with fineness ratios of 2.5, 3.0, 3.5, and 4.0 were made and then tested in the 8 by 8 wind tunnel; first, for cross-wind force, drag, and yawing moment at 30 miles an hour and various angles of yaw; next for drag 0 degree pitch and 0 degree yaw and various wind speeds; then for end effect on the smallest and largest models; and lastly for pressure distribution over the surface of the largest model at 0 degree pitch and 0 degree yaw and various wind speeds. In all tests, the length of the model was transverse to the current. The results are given for standard air density, p = .002378 slug per cubic foot. This account is a slight revised form of report no. 315. A summary of conclusions is given at the end of the text. (author).
Date: January 1, 1929
Creator: Zahm, A F; Smith, R H & Louden, F A
Partner: UNT Libraries Government Documents Department

Some studies on the aerodynamic effect of the gap between airplane wings and fuselages

Description: The general result indicated by this study is that if desirable from any viewpoint the gap between wing and fuselage may be closed without detrimental aerodynamic effects, and with a given monoplane there is less drag if the wing is directly on top of the fuselage than if it is parasol.
Date: November 1, 1929
Creator: Ober, Shatswell
Partner: UNT Libraries Government Documents Department

The impact on seaplane floats during landing

Description: In order to make a stress analysis of seaplane floats, and especially of the members connecting the floats with the fuselage, it is of great importance to determine the maximum pressure acting on the floats during landing. Here, the author gives a formula for maximum pressures during landing that permits one to apply experimental results to different bodies and different velocities. The author notes that the formula checks very well with experimental results.
Date: October 1, 1929
Creator: Von Karman, TH
Partner: UNT Libraries Government Documents Department