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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Memorandums
 Collection: National Advisory Committee for Aeronautics Collection
Aerodynamic Heat-Power Engine Operating on a Closed Cycle

Aerodynamic Heat-Power Engine Operating on a Closed Cycle

Date: November 1942
Creator: Ackeret, J. & Keller, D. C.
Description: Hot-air engines with dynamic compressors and turbines offer new prospects of success through utilization of units of high efficiencies and through the employment of modern materials of great strength at high temperature. Particular consideration is given to an aerodynamic prime mover operating on a closed circuit and heated externally. Increase of the pressure level of the circulating air permits a great increase of limit load of the unit. This also affords a possibility of regulation for which the internal efficiency of the unit changes but slightly. The effect of pressure and temperature losses is investigated. A general discussion is given of the experimental installation operating at the Escher Wyss plant in Zurich for a considerable time at high temperatures.
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Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

Date: January 1, 1947
Creator: Ackeret, J.; Feldmann, F. & Rott, N.
Description: The mutual influences of compression shocks and friction boundary layers were investigated by means of high speed wind tunnels.Schlieren optics provided a clear picture of the flow phenomena and were used for determining the location of the compression shocks, measurement of shock angles, and also for Mach angles. Pressure measurement and humidity measurements were also taken into consideration.Results along with a mathematical model are described.
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Experiments with an airfoil from which the boundary layer is removed by suction

Experiments with an airfoil from which the boundary layer is removed by suction

Date: August 1926
Creator: Ackeret, J; Betz, A & Schrenk, O
Description: Our attempts to improve the properties of airfoils by removing the boundary layer by suction, go back to 1922. The object of the suction is chiefly to prevent the detachment of the boundary layer from the surface of the airfoil. At large angles of attack, such detachment prevents the attainment of the great lift promised by the theory, besides greatly increasing the drag, especially of thick airfoils. This report gives results of those experiments.
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Investigations on wings with and without sweepback at high subsonic speeds

Investigations on wings with and without sweepback at high subsonic speeds

Date: November 1, 1951
Creator: Ackeret, Jakob; Rott, Nikolaus & Degen, Max
Description: Drag tests at zero lift have been made at Mach numbers from 0.7 to approximately 0.95 in the high speed wind tunnel of the Institute of Aerodynamics, ETH, Zurich, on a group of untapered wings of aspect ratio 3.25, having sweep angles of 0 degree and 35 degrees. For each sweep angle, a series of geometrically similar models was tested at a constant Reynolds number to provide a verification of computed tunnel blocking corrections. Tests were also made for wings having thickness ratios of 0.09 and 0.12 and the results compared with results predicted by von Karman's similarity law.
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The Magnus effect in theory and in reality

The Magnus effect in theory and in reality

Date: May 1, 1930
Creator: Ahlborn, F
Description: A discussion of the Flettner rotor is presented from a nautical and economic viewpoint, and although it was a failure, the experimental and theoretical inventions cannot be disregarded. The following critical and experimental investigation will show the relations and applicability of the theories and practical applications. The Magnus effect is described in detail and a discussion and critical review of the Magnus effect is included.
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Turbulence and mechanism of resistance on spheres and cylinders

Turbulence and mechanism of resistance on spheres and cylinders

Date: January 1932
Creator: Ahlborn, FR
Description: The nature of turbulent flow through pipes and around obstacles is analyzed and illustrated by photographs of turbulence on screens and straighteners. It is shown that the reversal of flow and of the resistance law on spheres is not explainable by Prandtl's turbulence in the boundary layer. The investigation of the analogous phenomena on the cylinder yields a reversal of the total field of flow. The very pronounced changes in pressure distribution connected with it were affirmed by manometric measurements on spheres by Professor O. Krell. The reversal in a homogenous nonvortical flow is brought about by the advance of the stable arrangement of Karman's dead air vortices toward the test object and by the substitution of an alternatingly one-sided or rotating but stable vortex formation in place of the initially symmetrical formation. This also explains the marked variations of the models.
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Experimental determination of local and mean coefficients of heat transfer for turbulent flow in pipes

Experimental determination of local and mean coefficients of heat transfer for turbulent flow in pipes

Date: February 1, 1954
Creator: Aladyev, I T
Description: An extensive investigation of the changes of the local and mean heat-transfer coefficients along the pipe length, and some results.
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Air cooling : an experimental method of evaluating the cooling effect of air streams on air-cooled cylinders

Air cooling : an experimental method of evaluating the cooling effect of air streams on air-cooled cylinders

Date: May 1927
Creator: Alcock, J F
Description: In this report is described an experimental method which the writer has evolved for dealing with air-cooled engines, and some of the data obtained by its means. Methods of temperature measurement and cooling are provided.
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Combustion of liquid fuels in diesel engine

Combustion of liquid fuels in diesel engine

Date: October 1, 1924
Creator: Alt, Otto
Description: Hitherto, definite specifications have always been made for fuel oils and they have been classified as more or less good or non-utilizable. The present aim, however, is to build Diesel engines capable of using even the poorest liquid fuels and especially the waste products of the oil industry, without special chemical or physical preparation.
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On the Calculation of Shallow Shells

On the Calculation of Shallow Shells

Date: December 1, 1956
Creator: Ambartsumyan, S. A.
Description: This paper considers a sufficiently thin shallow shell of nonzero Gaussian curvature. It also presents a system of symmetrically constructed differential equations, constructed by the mixed method through the stress function and the displpacement function.
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On the Theory of Anisotropic Shallow Shells

On the Theory of Anisotropic Shallow Shells

Date: December 1, 1956
Creator: Ambartsumyan, S. A.
Description: A numerical analysis of thin-walled shallow shells is presented. Equations of equilibrium and relations between deformations and stresses are included along with fundamental differential equations.
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Calculation of tapered monoplane wings

Calculation of tapered monoplane wings

Date: August 1, 1930
Creator: Amstutz, E
Description: The tapered wing shape increases the lift in the middle of the wing and thus reduces the bending moment of the lifting forces in the plane of symmetry. Since this portion of the wing is the thickest, the stresses of the wing material are reduced and desirable space is provided for stowing the loads in the wing. This statically excellent form of construction, however, has aerodynamic disadvantages which must be carefully weighed, if failures are to be avoided. This treatise is devoted to the consideration of these problems.
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Airplane stability in taxying

Airplane stability in taxying

Date: September 1, 1932
Creator: Anderlik, E
Description: The stability analysis of an airplane while rolling is much more simplified to the extent that it can be obtained for numerical data which can be put to practical use in the design of landing gear dimensions. Every landing gear type attains to a critical ground friction coefficient that decides the beginning of instability, i.e., nosing over. This study has, in addition, a certain interest for the use of wheel brakes.
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Experiments on autorotation

Experiments on autorotation

Date: September 1, 1926
Creator: Anderlik, E
Description: This article deals principally with Professor Bairstow's experiments on autorotation, in which the wing is free to rotate about an axis in its plane of symmetry, which axis is parallel with the direction of the wind.
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Formation of a vortex at the edge of a plate

Formation of a vortex at the edge of a plate

Date: March 1, 1956
Creator: Anton, Leo
Description: The flow about the plate of infinite width may be represented as a potential flow with discontinuity surfaces which extend from the plate edges. For prescribed form and vortex distribution of the discontinuity surfaces, the velocity field may be calculated by means of a conformal representation. One condition is that the velocity at the plate edges must be finite. However, it is not sufficient for determination of the form and vortex distribution of the surface. However, on the basis of a similitude requirement one succeeds in finding a solution of this problem for the plate of infinite width which is correct for the very beginning of the motion of the fluid. Starting from this solution, the further development of the vortex distribution and shape of the surface are observed in the case of a plate of finite width.
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The stresses in columns under combined axial and side loads

The stresses in columns under combined axial and side loads

Date: July 1, 1922
Creator: Arnstein, Karl
Description: The problem before us is to determine the total stresses in an axially loaded column of any degree of restraint which is also subject to transverse bending both from a uniformly distributed load and from concentrated loads.
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Investigation of certain wing shapes with sections varying progressively along the span

Investigation of certain wing shapes with sections varying progressively along the span

Date: April 1, 1931
Creator: Arsandaux, L
Description: This investigation has a double object: 1) the calculation of the general characteristics of certain wings with progressively varying sections; 2) the determination of data furnishing, in certain cases, some information on the actual distribution of the external forces acting on a wing. We shall try to show certain advantages belonging to the few wing types of variable section which we shall study and that, even if the general aerodynamic coefficients of these wings are not often clearly superior to those of certain wings of uniform section, the wings of variable section nevertheless have certain advantages over those of uniform section in the distribution of the attainable stresses.
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Some principles governing the establishment of meteorological stations along air routes

Some principles governing the establishment of meteorological stations along air routes

Date: March 1, 1922
Creator: Aujames, P
Description: The organization of a meteorological service for an air route involves the solution of two distinct problems: distribution and grouping of meteorological stations and communications. Experience gained in the establishment of two lines, Paris-Warsaw and Constantinople-Bucharest enables us to establish certain principles, which may be of interest to note here.
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Determination of the elastic constants of airplane tires

Determination of the elastic constants of airplane tires

Date: November 1, 1954
Creator: BOECKH
Description: For determination of the elastic constants of airplane tires which are required for the numerical calculations of the shimmy properties of nose and tail wheels, deformation measurements were carried out on four different tires. For this purpose, the tires were loaded in each case with a normal load and then with a lateral force, a tangential force, and a moment. Moreover, the weight and the mass moment of inertia about a vertical axis were determined for the various tires.
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:The fundamental principles of high-speed semi-diesel engines. Part II: a discussion of the semi-diesel principle and its application to various types of solid-injection engines

:The fundamental principles of high-speed semi-diesel engines. Part II: a discussion of the semi-diesel principle and its application to various types of solid-injection engines

Date: April 1, 1926
Creator: BUCHNER
Description: Three high-speed semi-diesel engines are examined through the use of indicator diagrams. Different fuel nozzles and fuels are investigated and conclusions are drawn.
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:The fundamental principles of high-speed semi-diesel engines. Part III: a discussion of fuel mixing and ignition, with special reference to engines with precombustion chambers

:The fundamental principles of high-speed semi-diesel engines. Part III: a discussion of fuel mixing and ignition, with special reference to engines with precombustion chambers

Date: April 1, 1926
Creator: BUCHNER
Description: A continuation of the discussion and overview of the present state of development of high-speed semi-diesel engines.
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The "Universal" adjustable and reversible propeller built by Paragon Engineers, Inc., Baltimore, Md

The "Universal" adjustable and reversible propeller built by Paragon Engineers, Inc., Baltimore, Md

Date: November 1, 1922
Creator: Bacon, David L
Description: A device which does for the aircraft what change speed gears do for the automobile is the invention of Spencer Heath. It comprises a system of special blades and a mechanism for varying the pitch of the blades from zero to 360 degrees, while in flight or otherwise.
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The "Universal propeller": built by Paragon Engineers, Inc., Baltimore, Md

The "Universal propeller": built by Paragon Engineers, Inc., Baltimore, Md

Date: March 1, 1922
Creator: Bacon, David L
Description: At the request of the N.A.C.A. the "Universal Propeller" was operated and explained by the inventor, Mr. Spencer Heath, for the purpose of demonstrating the following features of design: 1) Elimination of continuously running gears, collars or bearings in the pitch control mechanism; 2) The use of engine power in place of manual labor in changing blade angle; 3) The absence of any structural limitation to the range of blade angles available and the possibility of limiting the blade travel between any two predetermined extreme positions; 4) Continuous indication on the instrument board of the blade position; 5) Automatic throttling of the engine while the propeller is passing through the position of neutral pitch.
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Measurements on a low-wing model in the rotating jet and comparison with flight measurements

Measurements on a low-wing model in the rotating jet and comparison with flight measurements

Date: September 1, 1939
Creator: Bader, W
Description: The present report deals with six-component measurements in the small tunnel of the DVL on a model of the BFW-M 27b(sub 1), which were made to determine the effect of rolling and yawing on the air forces and moments. The wind was given a spiral motion by means of a rotating screen, the model being suspended in the conventional manner.
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