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Design of Recording Wind Tunnel Balances

Description: Given here is a description of the design of a scientific recording wind tunnel balance. It was decided that the most satisfactory arrangement would be a rigid ring completely surrounding the tunnel or wind stream, so that the model could be supported from it by wires or any arrangement of spindles. The forces and moments acting on this ring can then be recorded by suitable weighing apparatus. The methods available for recording forces on the arms are explained. The proposed type of balance will support the model rigidly in a variety of ways, will make a complete test without attention, and will plot the results so that all computations are avoided.
Date: December 1920
Creator: Norton, F. H.
Partner: UNT Libraries Government Documents Department
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High thermal efficiency in airplane service

Description: Described here is a method by which high average fuel economy has been achieved in aircraft engines. Details are given of the design of certain foreign engines that employ an unusual type of fuel-air ratio control in which the change in power produced by a mixture change is due almost entirely to the change in the power producing ability of the unit weight of the mixture. The safety and performance features of this type of control are explained.
Date: December 1920
Creator: Sparrow, S. W.
Partner: UNT Libraries Government Documents Department
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Instrument for measuring engine clearance volumes

Description: With the advent of the V type engine, a new method to measure the clearance volume in cylinders was needed. It was suggested that this measurement could be made by a process which consisted essentially of simultaneously changing both a known and unknown volume of gas by a known amount and then calculating the magnitude of the unknown from the resulting difference in pressure between the two. An instrument based on this design is described.
Date: December 1920
Creator: Sparrow, S. W.
Partner: UNT Libraries Government Documents Department
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Progress Made in the Construction of Giant Airplanes in Germany During the War

Description: The construction of giant airplanes was begun in Germany in August, 1914. The tables annexed here show that a large number of airplanes weighing up to 15.5 tons were constructed and tested in Germany during the War, and it is certain that no other country turned out airplanes of this weight nor in such large numbers. An examination of the tables shows that by the end of the War all the manufacturers had arrived at a well-defined type, namely an airplane of about 12 tons with four engines of 260 horsepower each. The aircraft listed here are discussed with regard to useful weight and aerodynamic qualities.
Date: December 1920
Creator: Baumann, A.
Partner: UNT Libraries Government Documents Department
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The Steadiness Factor in Engine Sets

Description: Technical notes discussing the steadiness factor in engines and the calculations that can be used to arrive at it. Factors affecting the steadiness factor are detailed, including the mass of parts, torque, engine rotation, and power.
Date: December 1920
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
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A Variable Speed Fan Dynamometer

Description: Fan brakes used as absorption dynamometers in testing internal combustion engines have the disadvantage that a given fan will run only at one speed when the engine is delivering full power. In order to be able to vary the speed at which a given power will be absorbed, English manufacturers have for some time been using a cylindrical housing around the fan with one or two variable openings in the periphery. Here, results are given of tests conducted to determine how great a range of speed can be obtained from such a device.
Date: December 1920
Creator: Wood, Karl D.
Partner: UNT Libraries Government Documents Department
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Analyses of Air from Burning Buildings

Description: This report provides results of analyses and pertinent fata regarding eleven samples taken from the composition of the air in burning buildings.
Date: November 1920
Creator: Katz, S. H.
Partner: UNT Libraries Government Documents Department
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Development of the Inflow Theory of the Propeller

Description: Report discusses the theory of inflow of the propeller and the fact that both suctional axial velocity and suctional tangential velocity must be considered when calculating the maximum efficiency.
Date: November 1920
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
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Göttingen Wind Tunnel for Testing Aircraft Models

Description: Given here is a brief description of the Göttingen 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 1920
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department
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Horizontal Buoyancy in Wind Tunnels

Description: Note presenting an examination of horizontal buoyancy in wind tunnels, including an examination of the relative flow, static pressure gradient, horizontal buoyancy computation, and methods of computation in practical use are provided.
Date: November 1920
Creator: Zahm, A. F.
Partner: UNT Libraries Government Documents Department
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Italian and French Experiments on Wind Tunnels

Description: Given here are the results of experiments conducted by Colonel Costanzi of the Italian Army to determine the influence of the surrounding building in which a wind tunnel was installed on the efficiency of the installation, and how the efficiency of the installation was affected by the design of the tunnel. Also given are the results of a series of experiments by Eiffel on 34 models of tunnels of different dimensions. This series of experiments was started in order to find out if, by changing the shape of the nozzle or of the diffuser of the large tunnel at Auteuil, the efficiency of the installation could be improved.
Date: November 1920
Creator: Knight, William
Partner: UNT Libraries Government Documents Department
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The Photographic Recording of Small Motions

Description: Methods and equipment for recording small and sometimes rapid motions by photographic means are described, and the efficacy of photographic recording in such instances is evaluated. The optical system consisting of the light source, the mirror or prism for transmitting motion to the emergent beam, and a means of bringing the rays into focus on the film are discussed. Attention is given to the critical issue of mirror mounting.
Date: November 1920
Creator: Norton, F. H.
Partner: UNT Libraries Government Documents Department
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Recent Developments in Light Alloys

Description: This report is intended to cover the progress that has been made in both the manufacture and utility of light alloys in the United States since the first part of 1919. Duralumin is extensively discussed both as to manufacture and durability.
Date: November 1920
Creator: Woodward, R. W.
Partner: UNT Libraries Government Documents Department
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Tests of Artificial Flight at High Altitudes

Description: "If we wish to form an accurate idea of the extraordinary progress achieved in aeronautics, a comparison must be made of the latest altitude records and the figures regarded as highest attainable limit some ten years ago. It is desirable, for two reasons, that we should be able to define the limit of the altitudes that can be reached without artificial aid. First, to know to what extent the human body can endure the inhalation of rarified air. Second, the mental capacity of the aviator must be tested at high altitudes and the limit known below which he is able to make reliable observations without being artificially supplied with oxygen" (p. 1).
Date: November 1920
Creator: Gradenwitz, Arthur
Partner: UNT Libraries Government Documents Department
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Variable Pitch Propellers

Description: In this report are described four different types of propellers which appeared at widely separated dates, but which were exhibited together at the last Salon de l'Aeronautique. The four propellers are the Chaviere variable pitch propeller, the variable pitch propeller used on the Clement Bayard dirigible, the variable pitch propeller used on Italian dirigibles, and the Levasseur variable pitch propeller.
Date: November 1920
Creator: Bacon, D. L.
Partner: UNT Libraries Government Documents Department
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Notes on Specifications for French Airplane Competitions

Description: Given here are the rules officially adopted by the Aeronautical Commission of the Aero Club of France for a flight competition to be held in France in 1920 at the Villacoublay Aerodrome. The prize will be awarded to the pilot who succeeds in obtaining the highest maximum and lowest minimum speeds, and in landing within the shortest distance.
Date: October 1920
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
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Recovery of Gold from Black Sand Tailings

Description: Report on the recovery of gold from black sand tailings, based on tests conducted at the U.S. Bureau of Mines' Alaska Station.
Date: October 1920
Creator: Gross, John
Partner: UNT Libraries Government Documents Department
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Talc Mining in New York

Description: Report issued by the U.S. Bureau of Mines on the talc deposits in New York state. The report includes details on the geology of the deposits, and the mining and milling of the talc. This report contains illustrations.
Date: October 1920
Creator: Ladoo, Raymond B.
Partner: UNT Libraries Government Documents Department
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Tests of the Daimler D-IVa Engine at a High Altitude Test Bench

Description: Reports of tests of a Daimler IVa engine at the test-bench at Friedrichshafen, show that the decrease of power of that engine, at high altitudes, was established, and that the manner of its working when air is supplied at a certain pressure was explained. These tests were preparatory to the installation of compressors in giant aircraft for the purpose of maintaining constant power at high altitudes.
Date: October 1920
Creator: Noack, W. G.
Partner: UNT Libraries Government Documents Department
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Drag or Negative Traction of Geared-Down Supporting Propellers in the Downward Vertical Glide of a Helicopter

Description: Discussed here are computations of drag or negative traction of geared down supporting propellers in the downward vertical glide of a helicopter. By means of Frounde's Theory, the maximum value of the drag of a windmill is calculated. For wooden propellers, the author finds that the difference between the drag and the weight is proportional to the number of blades and is larger for propellers of small diameter; thus it is 25 kg. for a six blade propeller with a diameter of 2 m. 50.
Date: September 1920
Creator: Toussaint, A.
Partner: UNT Libraries Government Documents Department
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The Dynamometer Hub

Description: The construction of the dynamometer hub is illustrated and explained, and its electrical and aviation motor tests, as well as those in free flight, described.
Date: September 1920
Creator: Stieber, W.
Partner: UNT Libraries Government Documents Department
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Experience With Geared Propeller Drives for Aviation Engines

Description: An overview is given of experience with geared propeller drives for aviation engines. The development of gear wheels is discussed with emphasis upon bending stresses, compressive stresses, heating, and precision in manufacturing. With respect to the general arrangement of gear drives for airplanes, some principal rules of mechanical engineering that apply with special force are noted.
Date: September 1920
Creator: Kutzbach, K.
Partner: UNT Libraries Government Documents Department
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Recent Efforts and Experiments in the Construction of Aviation Engines

Description: It became evident during World War I that ever-increasing demands were being placed on the mean power of aircraft engines as a result of the increased on board equipment and the demands of aerial combat. The need was for increased climbing efficiency and climbing speed. The response to these demands has been in terms of lightweight construction and the adaptation of the aircraft engine to the requirements of its use.
Date: September 1920
Creator: Schwager, [Otto]
Partner: UNT Libraries Government Documents Department
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Increase in Maximum Pressures Produced by Preignition in Internal Combustion Engines

Description: Report discusses the calculations that can be used to show why pressures inside an engine during preignition are higher than average. This information can be used to design a safer engine that is able to contain the increased pressure and heat generated during preignition.
Date: August 1920
Creator: Sparrow, S. W.
Partner: UNT Libraries Government Documents Department
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