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Aerodynamic Characteristics of Airfoils 6: Continuation of Reports Nos. 93, 124, 182, 244, and 286
"This collection of data on airfoils has been made from the published reports of a number of the leading aerodynamic laboratories of this country and Europe. The information which was originally expressed according to the different customs of the several laboratories is here presented in a uniform series of charts and tables suitable for use of designing engineers and for purposes of general reference. The authority for the results here presented is given as the name of the laboratory at which the experiments were conducted, with the size of the model, wind velocity, and year of test" (p. 213).
Aerodynamic Characteristics of Twenty-Four Airfoils at High Speeds
"If a propeller is mounted directly on the of a modern high-speed airplane engine, the outer airfoil sections of the propeller travel at speeds approaching the speed of sound. It is possible by the use of gearing and a somewhat larger propeller to reduce the speed of the propeller sections, but only at the expense of additional weight and some frictional loss of power. This report presents the results of this work" (p. 327).
Aircraft Woods: Their Properties, Selection, and Characteristics
From Summary: "This report presents, further, information on the properties of various other native species of wood compared with spruce, and discusses the characteristics of a considerable number of them from the standpoint of their possible application in aircraft manufacture to supplement the woods that are now most commonly used."
Annual Report of the National Advisory Committee for Aeronautics (15th). Administrative Report Including Technical Reports Nos. 309 to 336
Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, Congressional report, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
Coefficients of Flow of Standard Nozzles
We first undertook experiments with air, devoted principally to the investigation of the disturbances due to the differences in the nature of the flow to the nozzle. The difficulty of measuring the air, however, caused us to experiment with water. Due to the possibility of measuring the capacity of the container, this method was much more accurate than measuring with Pitot tobes.
Collection of wind-tunnel data on commonly used wing sections
This report groups in a uniform manner the aerodynamic properties of commonly used wing sections as determined from tests in various wind tunnels. The data have been collected from reports of a number of laboratories. Where necessary, transformation has been made to the absolute system of coefficients and tunnel wall interference corrections have been applied. Tables and graphs present the data in the various forms useful to the engineer in the selection of a wing section.
Combating Airplane Fires
This report provides a summary of the important steps to be taken in combating airplane fires. Some considerations and ways of preventing fires from developing are provided.
Contribution to the Study of Normal Burning in Gaseous Carbureted Mixtures: Part 1
In the present study it is proposed to provide an equipment permitting the study of the propagation of the region of reaction in mixtures of air and carbureted gases enclosed within a cylinder. Ignition is produced at the end of compression by an electric spark. With this apparatus it is proposed to determine: 1) the influence of the richness of the explosive mixture on the rate of flame propagation; 2) the influence of the degree of volumetric compression on one of the hydrocarbons; 3) the influence of the variation of initial temperature of the mixture before compression; 4) the influence of tetraethyl-lead on the propagation - notably on the formation of the explosive wave.
Contribution to the Study of Normal Burning in Gaseous Carbureted Mixtures: Part 2
Memorandum presenting the experimental results of tests to confirm the contribution to the study of normal burning in gaseous carbureted mixtures.
Flight tests on U.S.S. Los Angeles. Part 2: stress and strength determination
From Summary: "The tests described in this report furnished data on the actual aerodynamic forces, and the resulting stresses and bending moments in the hull of the U. S. S. "Los Angeles" during as severe still-air maneuvers as the airship would normally be subjected to, and in straight flight during as rough air as is likely to occur in service, short of squall or storm conditions. The maximum stresses were found to be within the limits provided for in accepted practice in airship design. Normal flight in rough air was shown to produce forces and stresses about twice as great as the most severe still-air maneuvers."
Fuel Vapor Pressures and the Relation of Vapor Pressure to the Preparation of Fuel for Combustion in Fuel Injection Engines
"This investigation on the vapor pressure of fuels was conducted in connection with the general research on combustion in fuel injection engines. The purpose of the investigation was to study the effects of high temperatures such as exist during the first stages of injection on the vapor pressures of several fuels and certain fuel mixtures, and the relation of these vapor pressures to the preparation of the fuel for combustion in high-speed fuel injection engines" (p. 385).
Joint report on standardization tests on N.P.L. R.A.F 15 airfoil model
From Summary: "This report contains the wind-tunnel test data obtained in the United States on a 36 by 6 inch R.A.F. 15 airfoil model prepared by the British Aeronautical Research Committee for International Trials. Tests were made in cooperation with the National Advisory Committee for Aeronautics at the Bureau of Standards, Langley Memorial Aeronautical Laboratory, Massachusetts Institute of Technology, and McCook field. In addition to brief descriptions of the various wind tunnels and methods of testing, the report contains an analysis of the test data. It is shown that while in general the agreement is quite satisfactory there are two cases in which it is unsatisfactory."
Rate of Heat Transfer From Finned Metal Surfaces
The object was to evaluate the factors which control the rate of heat transfer to a moving current of air from finned metal surfaces similar to those used on aircraft engine cylinders. This was to establish data which will enable the finning of cooling surfaces to be designed to suit the particular needs of any specific application. Most of the work was done on flat copper specimens 6 inches square, upon which were mounted copper fins with spacings varying from 1/2 inch to 1/12 inch. All fins were 1 inch deep, 6 inches long, and .020 inch thick. The results of the investigation are given in the form of curves included here.
Structural Details of the Giant Dornier Seaplane "Do X."
Memorandum presenting a description of the Dornier seaplane Do X. Details of the general description, materials, details of the main wing and upper wing, details of the hull and of the wing stubs, tail surfaces and control lines, power plant, and launching car and floating dock are provided.
Tests of Five Metal Model Propellers With Various Pitch Distributions in a Free Wind Stream and in Combination With Model VE-7 Fuselage
"This report describes the tests of five adjustable blade metal model propellers both in a free wind stream and in combination with a model fuselage with stub wings. The propellers are of the same form and cross section but have variations in radial distributions of pitch. By making a survey of the radial distribution of air velocity through the propeller plane of the model fuselage it was found that this velocity varies from zero at the hub center to approximately free stream velocity at the blade tip" (p. 501).
The Torsion of Members Having Sections Common in Aircraft Construction
"Within recent years a great variety of approximate torsion formulas and drafting-room processes have been advocated. In some of these, especially where mathematical considerations are involved, the results are extremely complex and are not generally intelligible to engineers. The principal object of this investigation was to determine by experiment and theoretical investigation how accurate the more common of these formulas are and on what assumptions they are founded and, if none of the proposed methods proved to be reasonable accurate in practice, to produce simple, practical formulas from reasonably correct assumptions, backed by experiment. A second object was to collect in readily accessible form the most useful of known results for the more common sections" (p. 675).
The Weymann-Lepère W.E.L. 10 Observation Airplane (French): A High-Wing Monoplane
Circular presenting a description of the Weymann-Lepère W.E.L. 10. Some of the characteristics described include the principles of the construction, aerodynamics, descriptions of the components, flight characteristics, and photographs and blueprints.
Wind-Tunnel Tests on a Series of Wing Models Through a Large Angle of Attack Range Part 1: Force Tests
"This investigation covers force tests through a large range of angle of attack on a series of monoplane and biplane wing models. The tests were conducted in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics. The models were arranged in such a manner as to make possible a determination of the effects of variations in tip shape, aspect ratio, flap setting, stagger, gap, decalage, sweep back, and airfoil profile. The arrangements represented most of the types of wing systems in use on modern airplanes" (p. 3).
The Design of Airplane Wing Ribs
"The purpose of this investigation was to obtain information for use in the design of truss and plywood forms, particularly with reference to wing ribs. Tests were made on many designs of wing ribs, comparing different types in various sizes. Many tests were also made on parallel-chord specimens of truss and plywood forms in place of the actual ribs and on parts of wing ribs, such as truss diagonals and sections of cap strips" (p. 223).
Airfoil Pressure Distribution Investigation in the Variable Density Wind Tunnel
Report presents the results of wind tunnel tests of pressure distribution measurements over one section each of six airfoils. Pressure distribution diagrams, as well as the integrated characteristics of the airfoils, are given for both a high and a low dynamic scale or, Reynolds number VL/V, for comparison with flight and other wind-tunnel tests, respectively. It is concluded that the scale effect is very important only at angles of attack near the burble.
Aircraft Accidents: Method of Analysis
The revised report includes the chart for the analysis of aircraft accidents, combining consideration of the immediate causes, underlying causes, and results of accidents, as prepared by the special committee, with a number of the definitions clarified. A brief statement of the organization and work of the special committee and of the Committee on Aircraft Accidents; and statistical tables giving a comparison of the types of accidents and causes of accidents in the military services on the one hand and in civil aviation on the other, together with explanations of some of the important differences noted in these tables.
Comparative Performance Obtained With XF7C-1 Airplane Using Several Different Engine Cowlings
Discussed here are problems with the use of cowlings with radial air cooled engines. An XF7C-1 airplane, equipped with service cowling and with narrow ring, wide ring, and exhaust collector ring cowlings over the service cowling, was used. For these four cowling conditions, the rate of climb and high speed performance were determined, the cylinder conditions were measured, and pictures to show visibility were taken. The level flight performance obtained with an engine speed of 1900 r.p.m. for the service type, the narrow ring, the wide ring, and the exhaust collector ring was 144.4, 146.6, 152.8, and 155 mph, respectively.
The Comper C(La)7 "Swift" Airplane (English): A High-Wing Single-Seat Monoplane
Circular describing the Comper C(La)7 Swift airplane, which is a high-wing single-seat monoplane with performance equal to that of a modern two-seat light airplane. Details of the view, aerodynamic design, wing, landing gear, cockpit, fuel tanks, engine, characteristics, drawings, and photographs are provided.
The Dornier "Do.X" Flying Boat (German) : A Giant High-Wing Monoplane
Circular presenting a description of the Dornier Do.X flying boat. Details are provided regarding the structural details, flying qualities, and photographs.
Experimental Investigations Concerning the Limits of Detonation in Gaseous Mixtures: Part 1
Memorandum presenting an investigation to determine quantitatively the limits of detonation in gaseous mixtures for the conditions imposed and for a number of given gaseous explosive mixtures.
Experimental Investigations Concerning the Limits of Detonation in Gaseous Mixtures: Part 2
Memorandum presenting an investigation concerning the limits of detonation in gaseous mixtures. In regards to the results, by progressive dilution of the explosive, the course of the chemical reaction becomes slower and slower until finally the transformation within the reaction zone becomes so slow that it is not there completed.
Injection Labs in a Common-Rail Fuel Injection System
Note presenting injection lags determined for a common-rail fuel injection system for a compression-ignition engine. The system consisted of a high-pressure reservoir, a timing valve, an injection valve tube, and an automatic injection valve. Results regarding the variable injection valve tube length, variable tube diameter, variable valve opening pressure, variable injection pressure, and variable initial pressure are provided.
The Lioré-Olivier "Le 0.240" Commercial Seaplane (French): A High-Wing Cantilever Monoplane
Circular presenting a description of the Le 0.240, which is a cantilever monoplane invented by the Lioré-Olivier Company. Information regarding the wings, profile, fuel tanks, construction, ailerons, hull, controls, and flight characteristics is provided.
A Method of Calculating the Ultimate Strength of Continuous Beams
The purpose of this study was to investigate the strength of continuous beams after the elastic limit has been passed. As a result, a method of calculation, which is applicable to maximum load conditions, has been developed. The method is simpler than the methods now in use and it applies properly to conditions where the present methods fail to apply.
Relation Between the Stability Characteristics and the Controllability of German Airplanes
This survey is intended to give a general approximate idea of the stability and controllability of German airplanes. Both flight characteristics, including the behavior of the airplane under the action of deflected controls and external disturbances, and flight performance, which refers to climbing, speed, take-off, and landing qualities.
The Relation Between the Tensile Strength and the Hardness of Metals
This report presents methods determining the hardness and tensile strength of metals by showing the effect and dependence of the hardness numbers on the strain-hardening. Relations between the hardness numbers and the ordinary stress-strain diagrams and tensile strength are given. Procedures for finding the Brinell strength are also presented.
Test of an Adjustable Pitch Model Propeller at Four Blade Settings
"This note describes tests of an adjustable blade metal model propeller, both in a free wind stream and in combination with a model fuselage, at four settings of the blades. The model propeller is designed for a uniform nominal pitch/diameter ratio of .7 and the blade settings used correspond to nominal pitch/diameter ratios of .5, .7, .9, and 1.1 at the .6 radius. The tests show that propellers of this type may be considerably changed in setting from the designed pitch angles and yet give excellent performance" (p. 1).
The Pressure Distribution Over the Wings and Tail Surfaces of a PW-9 Pursuit Airplane in Flight
This report presents the results of an investigation to determine (1) the magnitude and distribution of aerodynamic loads over the wings and tail surfaces of a pursuit-type airplane in the maneuvers likely to impose critical loads on the various subassemblies of the airplane structure, (2) To study the phenomenon of center of pressure movement and normal force coefficient variation in accelerated flight, and (3) to measure the normal accelerations at the center of gravity, wing-tip, and tail, in order to determine the nature of the inertia forces acting simultaneously with the critical aerodynamic loads. The results obtained throw light on a number of important questions involving structural design.
Strength of Welded Joints in Tubular Members for Aircraft
"The object of this investigation is to make available to the aircraft industry authoritative information on the strength, weight, and cost of a number of types of welded joints. This information will, also, assist the aeronautics branch in its work of licensing planes by providing data from which the strength of a given joint may be estimated. As very little material on the strength of aircraft welds has been published, it is believed that such tests made by a disinterested governmental laboratory should be of considerable value to the aircraft industry" (p. 323).
Comparative flight performance with an NACA Roots supercharger and a turbocentrifugal supercharger
This report presents the comparative flight results of a roots supercharger and a turbocentrifugal supercharger. The tests were conducted using a modified DH-4M2 airplane. The rate of climb and the high speed in level flight of the airplane were obtained for each supercharger from sea level to the ceiling. The unsupercharged performance with each supercharger mounted in place was also determined. The results of these tests show that the ceiling and rate of climb obtained were nearly the same for each supercharger, but that the high speed obtained with the turbocentrifugal was better than that obtained with the roots. The high-speed performance at 21,000 feet was 122 and 142 miles per hour for the roots and turbocentrifugal, respectively.
The Boundary Layer as a Means of Controlling the Flow of Liquids and Gases
According to one of the main propositions of the boundary layer theory the scarcely noticeable boundary layer may, under certain conditions, have a decisive influence on the form of the external flow by causing it to separate from the wing surface. These phenomena are known to be caused by a kind of stagnation of the boundary layer at the point of separation. The present report deals with similar phenomena. It is important to note that usually the cause (external interference) directly affects only the layer close to the wall, while its indirect effect extends to a large portion of the external flow.
The Dyle and Bacalan "DB 70" Commercial Airplane (French): An All-Metal High-Wing Monoplane
Report presenting a description of the Dyle and Balaclan DB 70, which is a commercial airplane with a very thick wing. Details of the fuselages, wings, passenger and pilot spaces, ability to function as an ambulance airplane, and flying qualities are provided.
The Effect of Wing Tip Floating Ailerons on the Autorotation of a Monoplane Wing Model
"The preliminary tests described here were made to determine the extent to which wing tip floating ailerons might be effective in reducing airplane spinning tendencies. The tests showed that initial spinning tendencies and rates of stable spinning could doubtless be reduced by the use of tip floating ailerons on an airplane. It also appears to be desirable to reduce to a minimum the interference between wing and aileron. This would serve to maintain uniformity of action at all angles of attack and enable calculation of the aileron characteristics" (p. 1).
The Electrodynamometric Balance of the Small Wind Tunnel of the French Service of Aeronautical Research
This investigation shows the attempt to improve the electrodynamomoter designed by Mr. Villey. The force to be measured acts on a flexible steel plate which is placed in front of a fixed plate. The deformation varies the original thickness of the layer of air between the two plates, thus causing a more rapid variation in the coefficient of electrostatic attraction of the two plates than in the capacity of the condenser formed by the dynamometer.
The "Latécoère 28" Commercial Airplane (French): A Ten Passenger High-Wing Monoplane
Report presenting a description of the Latécoère 28, a commercial monoplane. A detailed description of the design, flight characteristics, and special features are provided.
Measurement of Profile Drag on an Airplane in Flight by the Momentum Method: Part 1
The present report contains the results thus far obtained and is intended to form the basis of further tests on using the momentum method. The method of testing is presented in detail and the photographs taken during these tests are interpreted.
Measurement of Profile Drag on an Airplane in Flight by the Momentum Method: Part 2
The purpose of this section is to survey the present status of scientific knowledge of the causes which produce drag, in order, if possible, to establish the relation between the individual results and the actual phenomena which demonstrate the fundamental importance of surface conditions. A discussion of the boundary layer is followed by: relations between frictional and form drag, application to profile-drag measurements, and different kinds of roughness. High-pressure wind tunnel tests are discussed along with roughness and maximum lift.
Les Mureaux "130.a2" Observation Airplane (French): A High-Wing Two-Seat Monoplane
Circular presenting Les Mureaux 130.A2, which is a high-wing two-seat observation monoplane. A description of the design, performances, components, performance qualities, photographs, and drawings are provided.
The Structure and Properties of Parachute Cloths
"The requisite properties of a parachute cloth are discussed and the methods for measuring these properties described. In addition to the structural analysis of the cloths, the properties measured were weight, breaking strength, tear resistance, elasticity, and air permeability. Thirty-six silk cloths of domestic manufacture, not previously used in parachute construction are compared with some silk cloths of foreign manufacture" (p. 1).
Temperature coefficient of the modulus of rigidity of aircraft instrument diaphragm and spring materials
Experimental data are presented on the variation of the modulus of rigidity in the temperature range -20 to +50 degrees C. of a number of metals which are of possible use for elastic elements for aircraft and other instruments. The methods of the torsional pendulum was used to determine the modulus of rigidity and its temperature coefficient for aluminum, duralumin, monel metal, brass, phosphor bronze, coin silver, nickel silver, three high carbon steels, and three alloy steels. It was observed that tensile stress affected the values of the modulus by amounts of 1 per cent or less.
An Extended Theory of Thin Airfoils and Its Application to the Biplane Problem
"The report presents a new treatment, due essentially to von Karman, of the problem of the thin airfoil. The standard formulae for the angle of zero lift and zero moment are first developed and the analysis is then extended to give the effect of disturbing or interference velocities, corresponding to an arbitrary potential flow, which are superimposed on a normal rectilinear flow over the airfoil. An approximate method is presented for obtaining the velocities induced by a 2-dimensional airfoil at a point some distance away" (p. 637).
The 1929 Rhon soaring-flight contest
The limitation of the 1929 contest to performance gliders necessitated the establishment of a formula which would make it possible to distinguish between performance gliders and school and training gliders. The sinking speed was therefore adopted as the basis for such a distinction, and the requirement was made that the sinking speed of a performance glider should not exceed 0.8 m/s. The rest of the report details the different entries with regard to design and performance.
Experimental Investigation of Aircraft Propellers Exposed to Oblique Air Currents
"Two screw propellers, a normal airplane propeller with a pitch/diameter ratio H/D = 0.5 and a helicopter propeller H/D = 0.2 were tested in the large wind tunnel of the Gottigen Aerodynamic Institute. With both propellers the angle between the propeller axis and the direction of the wind was varied from 0 to 90 degrees. In addition to the three force and the three moment components in a wind-fast coordinate system, the corresponding components in a propeller-fast coordinate system, a total of six force and six moment components, together with the propulsive efficiency, were measured or calculated from measurements" (p. 1).
The Farman "F.300" Commercial Airplane (French): A High-Wing Semicantilever Monoplane
Circular describing the Farman F.300 airplane, which is a high-wing semicantilever monoplane. Details of the wings, engine, equipment, safety, characteristics, performance, drawings, and photographs are provided.
Improving the Performance of Multi-Engined Airplanes by Means of Idling Propellers: The "Free-Wheel" Propeller
In order to demonstrate the importance of free-wheeling propellers, this report considers the braking effect of a propeller on a stopped engine when the propeller is rigidly connected with the engine shaft and also when mounted on a free-wheel hub. The cases of propellers of asymmetric and symmetric section are discussed. The author describes the mechanism of the free-wheel propeller as constructed for this test. The results obtained with the device mounted on a 1,000 horsepower two-engine airplane are given.
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