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open access

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.
open access

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.
open access

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.
open access

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]
open access

The Effect of Staggering a Biplane

Description: This investigation was carried out by request of the United States Air Service at the Massachusetts Institute of Technology wind tunnel in 1918. As the data collected may be of general interest, they are published here by the National Advisory Committee for Aeronautics. The lift, drag, and center of pressure travel are determined for a biplane with a stagger varying from +100% to -100%. It is found that the efficiency and the maximum lift increase with positive stagger.
Date: September 1921
Creator: Norton, F. H.
open access

Lift Theory of Supporting Surfaces: Second Article

Description: Memorandum presenting a description of the hydrodynamic lift theory of supporting services. This report is mainly about the task of finding suitable wing sections for given lift conditions. Formulas are given for lift magnitude and moment, which make it possible to obtain solutions of great simplicity and clearness.
Date: September 1921
Creator: von Mises, R.
open access

A New Dynamometer Brake

Description: The mechanism here described belongs to the class of dynamometer brake in which the motive power is transformed into heat in the brake itself. This mechanism was invented by the writer for the purpose of measuring forces in which the two factors, torque and speed, vary within broad limits, the mechanism itself being of simple construction and of still simpler operation.
Date: September 1921
Creator: SegrĆØ, Marco
open access

Performance of a vane driven-gear pump

Description: Given here are the results of a test conducted in a wind tunnel on the performance of a vane-driven gear pump used to pump gasoline upward into a small tank located within the upper wing from which it flows by gravity to the engine carburetor. Information is given on the efficiency of the pump, the head resistance of the vanes, the performance and characteristics of the unit with and without housing about the vanes, the pump performance when motor driven, and resistance and power characteristicā€¦ more
Date: September 1921
Creator: Heald, R. H.
open access

Aerodynamic Computation of Gliders

Description: From Introduction: "In the following discussion, a knowledge of the theoretical principles of airplane construction is assumed, as presented in detail by Vogt and Lippisch in Nos. 7 and 10-19 of the 1919 volume of this publication. A few quantities will however be otherwise designated, in accordance with the Gottingen symbols."
Date: September 1922
Creator: Schrenk, M.
open access

Aerodynamic Laboratory at Cuatro Vientos

Description: This report presents a listing of the many experiments in aerodynamics taking place at Cuatro Vientos. Some of the studies include: testing spheres, in order to determine coefficients; mechanical and chemical tests of materials; and various tests of propeller strength and flexibility.
Date: September 1922
Creator: Jubera
open access

The Disposal of Military Aircraft

Description: "The end of the war saw every belligerent with vast stocks of aircraft and aircraft supplies in all stages of usefulness, much of the material being absolutely new. The question of the best method of getting rid of this accumulation is one which has been agitating those responsible for its disposal for more than three years now, but no wholly satisfactory solution has yet been reached" (p. 1).
Date: September 1922
Creator: Warner, Edward P.
open access

The Effect on Rudder Control of Slip Stream Body, and Ground Interference

Description: "This investigation was undertaken to determine the relative effects of those factors which may interfere with the rudder control of an airplane, with especial reference to the process of landing. It shows that ground interference is negligible, but that the effects of a large rounded body and of the slip stream may combine to interfere seriously with rudder control at low flying speeds and when taxiing" (p. 1).
Date: September 1922
Creator: Hoot, H. I. & Bacon, D. L.
open access

Fatigue Resistance of Duralumin

Description: Where, in the following report, mention is made of fatigue, it always refers to the weakening of the material produced by rapidly changing stresses below the point of elasticity. The alternating stress was obtained by a test bar which was held at one end and subjected to rotation. Most of the tests were conducted on connecting rods.
Date: September 1922
open access

Giant Airplanes

Description: It is hardly possible for the most imaginative aeronautical enthusiast to look forward to a time when the airplane will have reached the dimensions commensurate with those already attained by the airship.
Date: September 1922
Creator: Warner, Edward P.
open access

Miniature Airplanes

Description: The present report will treat only the smallest airplanes equipped with engines. The two types discussed are those airplanes with the smallest dimensions, and those that have the smallest power requirements.
Date: September 1922
Creator: Warner, Edward P.
open access

The Prevention of Fire in the Air

Description: On an airplane, the safeguards adopted may be divided into three classes, those intended to prevent a fire from getting started, those intended to put it out if it does get under way, and, finally, those designed to limit the damage which a fire can do. Some of the fire-related elements discussed include protecting the gasoline, fire extinguishers, a flame-tight bulkhead, and airship hazards.
Date: September 1922
Creator: Warner, Edward P.
open access

Problem of Glider Models

Description: Any one endeavoring to solve the problem of soaring flight is confronted not only by structural difficulties, but also by the often far more difficult aerodynamic problem of flight properties and efficiency, which can only be determined by experimenting with the finished glider. The report primarily considers open-air experiments with glider models and some specific elements of gliders that have been studied using these experiments.
Date: September 1922
Creator: Espenlaub, Lippisch
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