Technical Report Archive and Image Library (TRAIL) - 116 Matching Results

Search Results

Wire suspensions in wind tunnel experiments

Description: The elimination of the rigid supports for models and their replacement by wires constitute a great improvement by rendering negligible the interactions of support. There are disadvantages to wire, namely, the aerodynamic resistance is very large and their use is rather difficult because the whole suspension lacks rigidity and easily becomes distorted. We will here investigate the nature of these distortions, evaluate the errors they entail and describe the methods for taking account of or avoiding them.
Date: December 1, 1925
Creator: Kerneis, Jean
Partner: UNT Libraries Government Documents Department

The light airplane: modern theoretical aerodynamics as applied to light airplane design with a series of charts

Description: T.M. 311 gave a short outline of modern theoretical aerodynamics as applied to light airplane design. This discussion may have been somewhat obscure to the nontechnical reader. A series of charts or curves should serve to clear up such obscurity as well as to more definitely emphasize those quantities most important for each flight characteristic.
Date: August 1, 1925
Creator: Driggs, Ivan H.
Partner: UNT Libraries Government Documents Department

The Light Airplane

Description: This report begins with a review and analysis of the work being done to develop light airplanes in the U.S. and abroad. A technical discussion of the construction and innovations in light airplanes is then presented.
Date: April 1925
Creator: Driggs, Ivan H.
Partner: UNT Libraries Government Documents Department

Light aeroplane engine development

Description: It has frequently been stated and written that in order to popularize light aircraft the first essential is the production of a reliable engine capable of being easily maintained and having a long life, at the same time selling at a low figure. It is desired to point out the difficulties in the way of realizing this ideal before remarking on the claims of the various types for adoption.
Date: April 1, 1925
Creator: Fell, L. F. R.
Partner: UNT Libraries Government Documents Department

Potential flow in engine valves

Description: The extensive applicability of the hydrodynamic theory to the problems of engine construction is clearly shown in the following attempt to determine by exact methods the nature of the flow in valves under variously restricted conditions. Observation shows that two principal kinds of flow occur in simple flat-seated valves. For small valve lifts, the flow is along the horizontal wall and is therefore deflected 90 degrees, but for greater valve lifts the flow separates and forms a free stream, whose angle of deflection naturally increases with increasing lift. Both these kinds of flow can, in fact, be theoretically explained.
Date: December 1, 1925
Creator: Eck, Bruno
Partner: UNT Libraries Government Documents Department

Pressure distribution over the wings of an MB-3 airplane in flight

Description: This investigation was carried out to determine the distribution of load over the wings of a high speed airplane under all conditions of flight. In particular it was desired to find the pressure distribution during level flight, over the portions of the wings in the slipstream and, during violent maneuvers, over the entire wing surface. The method used consisted in connecting a number of holes in the surface of the wings to recording multiple manometers mounted in the fuselage of the airplane. In this way simultaneous records could be taken on all of the holes for any desired length of time. (author).
Date: January 1, 1925
Creator: Norton, F. H.
Partner: UNT Libraries Government Documents Department

Atomization of liquid fuels. Part II

Description: This report describes the design and operation of a nozzle to inject fuel into an engine. The design of the nozzle is open, without any compulsory or automatic stop-valve. The fuel injection is regulated simply by the pressure and the adjustment of the fuel pump.
Date: September 1925
Creator: Kuehn, R
Partner: UNT Libraries Government Documents Department

Astronomical methods in aerial navigation

Description: The astronomical method of determining position is universally used in marine navigation and may also be of service in aerial navigation. The practical application of the method, however, must be modified and adapted to conform to the requirements of aviation. Much of this work of adaptation has already been accomplished, but being scattered through various technical journals in a number of languages, is not readily available. This report is for the purpose of collecting under one cover such previous work as appears to be of value to the aerial navigator, comparing instruments and methods, indicating the best practice, and suggesting future developments. The various methods of determining position and their application and value are outlined, and a brief resume of the theory of the astronomical method is given. Observation instruments are described in detail. A complete discussion of the reduction of observations follows, including a rapid method of finding position from the altitudes of two stars. Maps and map cases are briefly considered. A bibliography of the subject is appended.
Date: 1925
Creator: Beij, K. Hilding
Partner: UNT Libraries Government Documents Department

Atomization of liquid fuels. Part I

Description: In the present treatise we will consider chiefly the problem of solid injection in comparison with air injection. On leaving the valve or nozzle through one or more small openings, the fuel is split up into innumerable fine drops, which penetrate the combustion chamber in divergent directions in the form of a conical jet. The efficiency of this jet is judged from the following three viewpoints: 1) with respect to the fineness of atomization; 2) with respect to the direction or distribution of sprayed particles; 3) with respect to the penetration of the particles.
Date: September 1925
Creator: Kuehn,
Partner: UNT Libraries Government Documents Department

Calculation of wing spars of variable cross-section and linear load

Description: The calculation of wing spars of constant cross-section and load has been thoroughly treated by a large number of authors. Such is not the case,however, regarding the calculation of wing spars whose section and linear load diminish toward the ends, as in wings of trapezoidal contour and decreasing section.
Date: March 1, 1925
Creator: Kirste, Leon
Partner: UNT Libraries Government Documents Department

Aeronautic instruments. Section 1: general classification of instruments and problems including bibliography

Description: This report is intended as a technical introduction to the series of reports on aeronautic instruments. It presents a discussion of those subjects which are common to all instruments. First, a general classification is given, embracing all types of instruments used in aeronautics. Finally, a classification is given of the various problems confronted by the instrument expert and investigator. In this way the following groups of problems are brought up for consideration: problems of mechanical design, human factor, manufacturing problems, supply and selection of instruments, problems concerning the technique of testing, problems of installation, problems concerning the use of instruments, problems of maintenance, and physical research problems. This enumeration of problems which are common to instruments in general serves to indicate the different points of view which should be kept in mind in approaching the study of any particular instrument.
Date: 1925
Creator: Hersey, Mayo D.
Partner: UNT Libraries Government Documents Department

Elements of the Wing Section Theory and of the Wing Theory

Description: This report contains those results of the theory of wings and of wing sections which are of immediate practical value. They are proved and demonstrated by the use of the simple conceptions of "kinetic energy" and "momentum" only, familiar to every engineer; and not by introducing "isogonal transformations" and "vortices," which latter mathematical methods are not essential to the theory and better are used only in papers intended for mathematicians and special experts.
Date: January 1, 1925
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Accelerations in flight

Description: Report discussung work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.
Date: 1925
Creator: Doolittle, J H
Partner: UNT Libraries Government Documents Department

An introduction to the helicopter

Description: It is the object of this report to review briefly the aerodynamic and construction data already available and to set forth the difficulties which must be met.
Date: January 1, 1925
Creator: Klemin, Alexander
Partner: UNT Libraries Government Documents Department

Preliminary investigation of the effect of a rotating cylinder in a wing

Description: Into the leading edge of a wing with arbitrary cross-section, there is introduced a cylinder, which can be rotated by an electric motor by means of a cord. Observations were made in the wind tunnel on how the lift at different wind velocities was affected by rotating this cylinder.
Date: March 1, 1925
Creator: Wolff, E B
Partner: UNT Libraries Government Documents Department

Pitot-static tubes for determining the velocity of air

Description: On the occasion of the formulation of the rules for testing the efficiency of ventilators and compressors, experiments were instituted by the subcommittee on ventilators for the production of suitable tubes for velocity and pressure measurements.
Date: February 1, 1925
Creator: Kumbruch, H.
Partner: UNT Libraries Government Documents Department

Pressure Distribution on Joukowski Wings and Graphic Construction of Joukowski Wings

Description: In the first article, in connection with a lecture on the hydrodynamic basis of flight and the potential flow about a Joukowski wing, the pressure distribution on several wings is computed and plotted. The diagrams of the pressure distributions are presented accompanied with a qualitative discussion of the pressure distribution. In the second article, the the cross-sectional outline (or profile) a Joukowski wing are plotted.
Date: October 1, 1925
Creator: Blumenthal, Otto & Trefftz, E.
Partner: UNT Libraries Government Documents Department

The effects of shielding the tips of airfoils

Description: Tests have recently been made at Langley Memorial Aeronautical Laboratory to ascertain whether the aerodynamic characteristics of an airfoil might be substantially improved by imposing certain limitations upon the air flow about its tips. All of the modified forms were slightly inferior to the plain airfoil at small lift coefficients: however, by mounting thin plates, in planes perpendicular to the span, at the wing tips, the characteristics were improved throughout the range above three-tenths of the maximum lift coefficient. With this form of limitation the detrimental effect was slight; at the higher lift coefficients there resulted a considerable reduction of induced drag and consequently, of power required for sustentation. The slope of the curve of lift versus angle of attack was increased.
Date: January 1, 1925
Creator: Reid, Elliott G
Partner: UNT Libraries Government Documents Department

Correcting horsepower measurements to a standard temperature

Description: This report discusses the relation between the temperature of the air at the entrance to the carburetor and the power developed by the engine. Its scope is limited to a consideration of the range of temperatures likely to result from changes of season, locality, or altitude, since its primary aim is the finding of a satisfactory basis for correcting power measurements to a standard temperature. The tests upon which this report is based were made upon aviation engines in the Altitude Laboratory of the Bureau of Standards. From the results of over 1,600 tests it is concluded that if calculations be based on the assumption that the indicated horsepower of an engine varies inversely as the square root of the absolute temperature of the carburetor air the values obtained will check closely experimental measurements. The extent to which this relationship would be expected from theoretical considerations is discussed and some suggestions are given relative to the use of this relationship in correcting horsepower measurements. (author).
Date: January 1, 1925
Creator: Sparrow, Stanwood W
Partner: UNT Libraries Government Documents Department

The application of propeller test data to design and performance calculations

Description: This report is a study of a test data on a family of Durand's propellers (nos. 3, 7, 11, 82, 113, 139), which is fairly representative of conventional design. The test data are so plotted that the proper pitch and diameters for any given set of conditions are readily obtained. The same data are plotted in other forms which may be used for calculating performance when the ratio of pitch to diameter is known. These new plots supply a means for calculating the performance, at any altitude, of airplanes equipped with normal or supercharged engines. The coefficients used and the methods of plotting adopted in this report coordinate the results of a few tests into complete families of curves covering the entire range of p/d ordinarily used. This method of analyzing test data enables an investigator to plan tests systematically and leads to useful application of test data.
Date: January 1925
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department