National Advisory Committee for Aeronautics (NACA) - 1,272 Matching Results

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The formation of ice upon exposed parts of an airplane in flight

Description: In order to experimentally study the conditions leading to ice formation on aircraft surfaces, an aircraft was equipped with small auxiliary surfaces and aerodynamic shapes similar to struts, wires, Pitot heads, etc. This airplane was flown at an altitude where a temperature of 32 F was encountered, at such times as cloud formations could be found at the coincident altitude. Here it was discovered that ice formed rapidly in regard to quantity,character, shape, and rapidity of formation. An examination of this data, which confirms observations of pilots, indicates that the weight of ice collected can very possibly be sufficient to force the airplane to rapidly lose altitude on account of the increased loads. However, it is more evident that the malformation of the aerodynamic shapes may so increase the drag and reduce the lift so as to produce a loss of altitude even greater in consequence, the combination of the two working in the same direction having a double effect. Other adverse consequences are noted. The recommendation for the guidance of those who must encounter these conditions appears to lie entirely along the lines of avoidance.
Date: July 1, 1928
Creator: Carroll, Thomas & Mcavoy, Wm H
Partner: UNT Libraries Government Documents Department

Langley Field wind tunnel apparatus

Description: The difficulties experienced in properly holding thin tipped or tapered airfoils while testing on an N.P.L. type aerodynamic balance even at low air speeds, and the impossibility of holding even solid metal models at the high speeds attainable at the National Advisory Committee's wind tunnel, necessitated the design of a balance which would hold model airfoils of any thickness and at speeds up to 150 m.p.h. In addition to mechanical strength and rigidity, it was highly desirable that the balance readings should require a minimum amount of correction and mathematical manipulation in order to obtain the lift and drag coefficients and the center of pressure. The balance described herein is similar to one in use at the University of Gottingen, the main difference lying in the addition of a device for reading the center of pressure directly, without the necessity of any correction whatsoever. Details of the design and operation of the device are given.
Date: October 1, 1921
Creator: Bacon, D L
Partner: UNT Libraries Government Documents Department

Static testing and proposed standard specifications

Description: Static tests fall into two groups, the first of which is designed to load all members of the structure approximately in accordance with the worst loads which they carry in flight, while the second is directed to the testing of specific members which are suspected of weakness and which are difficult to analyze mathematically. The nature of the loading in the second type is different for every different test, but the purpose of the first is defined clearly enough to permit the adoption of some standard set of loading specifications, at least for airplanes of normal design. Here, an attempt is made to carry through an analysis leading to such a standard, the goal being the determination of a load which will simultaneously impose on every member of the airplane structure a stress equal to the worst it will carry in flight.
Date: July 1, 1920
Creator: Warner, E P
Partner: UNT Libraries Government Documents Department

The optical wing aligning device of the Langley Field tunnel

Description: Described here is a convenient and accurate method of aligning the wing chord with the airflow. The device was developed to permit rapid and accurate alignment of airfoils and models with the airstream passing through the tunnel. It consists of three main parts: a projector, a reflector, and a target. The arrangement, which is shown in a figure, has proven satisfactory in operation. It is far better than the old method of sighting across a long batten, as the operator of a balance may see the target and correctly judge the accuracy of his alignment. Whereas the old method required two operators and several minutes time to align to within 1/10 degree, this method enables one operator to align a wing to within 1/100 of a degree in a few seconds. This method also has the advantage of being able to measure the angle of the wing while the tunnel is running. Thus, the true angle of incidence is shown.
Date: January 1, 1921
Creator: Norton, F. H. & Bacon, D. L.
Partner: UNT Libraries Government Documents Department

The NACA three component accelerometer

Description: A new instrument known as the NACA three component accelerometer is described in this note. This instrument was designed by the technical staff of the NACA for recording accelerations along three mutually perpendicular axes, and is of the same type as the NACA single component accelerometer with the addition of two springs and a few minor improvements such as a pump for filling the dash-pots and a convenient method for aligning the springs. This note includes a few records as well as photographs of the instrument itself.
Date: October 1, 1922
Creator: Reid, H. J. E.
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

Resistance of streamline wires

Description: This note contains the results of tests to determine the resistance of four sizes of streamline wire. The investigation was conducted in the six-inch wind tunnel of the National Advisory Committee for Aeronautics. The tests were made at various velocities and it was found that the resistance of streamline wires was considerably less than that of round wires of equivalent strength. Scale effect was also found since, with an increase of Reynolds Number, a decrease in the resistance coefficient was obtained.
Date: March 1, 1928
Creator: Defoe, George L
Partner: UNT Libraries Government Documents Department

The effect of fillets between wings and fuselage on the drag and propulsive efficiency of an airplane

Description: Tests were made to determine the effect of fillets between wings and fuselage on the drag and propulsive efficiency of a high-wing cabin monoplane. These tests were made in the 20-foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics.
Date: October 1, 1928
Creator: Gough, Melvin N
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

Effect of the reversal of air flow upon the discharge coefficient of Durley Orifices

Description: Experiments were conducted to obtain information on the relationship between the coefficients for flow in two directions through thin plate orifices at low velocities. The results indicate that the ratio of the orifice discharge coefficient from standard orifice C(sub s)(sup 1) to the discharge coefficient from the reverse flow C(sub s) is always less than unity with increasing ratio of box area to orifice area. Even for areas as low as twenty, the ratios of the coefficients are not much less than unity. It is probable, however, that when the ratio of box area is less than twenty, the ratio of discharge coefficients would be greatly reduced. Specific results are given for the case of an apparatus for the laboratory testing of superchargers.
Date: February 1, 1921
Creator: Ware, Marsden
Partner: UNT Libraries Government Documents Department

An investigation of the characteristics of steel diaphragms for automatic fuel-injection valves

Description: This research on steel diaphragms was undertaken at the Langley Memorial Aeronautical Laboratory, as a part of a general investigation on fuel injection engines for aircraft. The work determined the load-deflection, load- deformation and hysteresis characteristics for single diaphragms having thicknesses from 0.00s inch to 0.012 inch, and for similar diaphragms tested in multiple having total thicknesses from 0.012 inch to 0.180 inch. The elastic limit loads and deflections, and rupture points of single diaphragms were also determined. Some work was done on diaphragms having central orifices in order to determine the effect of orifice diameter upon the load deflection characteristics.
Date: April 1, 1926
Creator: Joachim, W F
Partner: UNT Libraries Government Documents Department

Influence of the orifice on measured pressures

Description: The influence of different orifices on the result of measuring the same pressure distributions is the subject of this note. A circular cylinder is exposed to an air stream perpendicular to its axis and its pressure distribution is repeatedly determined. The pressures measured on the downstream half of the cylinder do not change for the orifice sizes used in the tests.
Date: November 1, 1926
Creator: Hemke, Paul E
Partner: UNT Libraries Government Documents Department

Gottingen Wind Tunnel for testing aircraft models

Description: Given here is a brief description of the Gottingen Wind Tunnel for the testing of aircraft models, preceded by a history of its development. Included are a number of diagrams illustrating, among other things, a sectional elevation of the wind tunnel, the pressure regulator, the entrance cone and method of supporting a model for simple drag tests, a three-component balance, and a propeller testing device, all of which are discussed in the text.
Date: November 1, 1920
Creator: Prandtl, L
Partner: UNT Libraries Government Documents Department

Syphon diaphragms : a method for predicting their performance for purposes of instrument design

Description: Here, the purpose is to show that the characteristic performance of a syphon diaphragm can be predicted from a knowledge of its stiffness and of its dimensions. The proof is based on a mathematical analysis of this type of diaphragm, together with enough experimental data to prove the validity of the assumptions and the sufficiency of the analysis. Equations are developed for the performance of syphons under various conditions of loading, both for concentrated loads and for hydrostatic pressure.
Date: January 1, 1922
Creator: Eaton, H N & Keulegan, G H
Partner: UNT Libraries Government Documents Department

Surface area coefficients for airship envelopes

Description: In naval architecture, it is customary to determine the wetted surface of a ship by means of some formula which involves the principal dimensions of the design and suitable constants. These formulas of naval architecture may be extended and applied to the calculation of the surface area of airship envelopes by the use of new values of the constants determined for this purpose. Surface area coefficients were calculated from the actual dimensions, surfaces, and volumes of 52 streamline bodies, which form a series covering the entire range of shapes used in the present aeronautical practice.
Date: February 1, 1922
Creator: Diehl, W S
Partner: UNT Libraries Government Documents Department

Tests of oil scraper piston ring and piston fitted with oil drain holes

Description: Tests were conducted to determine whether or not a properly located and properly designed oil scraper piston ring, installed on a piston provided with oil drain holes of sufficient area, would prevent the excessive oiling of the Liberty engine, particularly with the engine running at idling speed with full oil pressure. Results showed that excessive oiling was in fact prevented. It is strongly recommended that scraper rings and pistons be adopted for aircraft engines.
Date: August 1, 1922
Creator: Mcdewell, H S
Partner: UNT Libraries Government Documents Department

Ground influence on airfoils

Description: The question of ground influence on airplanes has recently attracted some attention in view of the claims made by certain designers that the landing speed of their airplanes is much decreased by an increase in lift coefficient due to the proximity of the ground in landing. The results of wind tunnel tests indicate that ground effect is not entirely beneficial. It decreases the landing speed and cushions the landing shock somewhat. However, it does so at the expense of an increased length of preliminary skimming over the ground. By decreasing the drag and increasing the lift, it lengthens the distance necessary for the airplane to travel before losing enough speed to land. On the other hand, its influence is helpful in taking off, especially in the case of flying boats with their low-lying wings. In the conventional tractor airplane, the height of the wings above the ground is determined largely by propeller clearance. However, a small low-speed airplane like the Pischoff and large low-speed commercial aircraft with engines between wings can utilize ground influence to good advantage.
Date: December 1, 1921
Creator: Raymond, Arthur E
Partner: UNT Libraries Government Documents Department

Micarta propellers III : general description of the design

Description: The design of propellers made of Micarta is discussed. The advantages of the material are noted, especially as compared with wood. The design changes necessitated by the use of Micarta are discussed with reference to the hub boss, the narrowing of the blade tips, the thinning of the blades, the angles of the leading and trailing edges, and the adjustment of the pitch. Results of flight tests show that the Micarta propeller gave a top speed of 2 miles per hour more than the wooden propeller while turning about 120 r.p.m slower, with about the same rate of climb. At top speed, the Micarta propeller shows an improvement of about 7 percent in fuel economy, although the plane is flying 2 miles per hour faster.
Date: August 1, 1924
Creator: Caldwell, F W & Clay, N S
Partner: UNT Libraries Government Documents Department

Technical preparation of the airplane "Spirit of St. Louis."

Description: Given here is a brief history of the design and construction of the "Spirit of St. Lewis", the airplane that Charles Lindbergh flew solo across the Atlantic. Although the plan was to modify a standard model Ryan M-2, it was quickly determined that modification was less practical than redesign. Colonel Lindbergh's active participation in the design of the aircraft is noted. Given here are the general dimensions, specifications, weight characteristics, and man hours required to build the aircraft.
Date: July 1, 1927
Creator: Hall, Donald A
Partner: UNT Libraries Government Documents Department