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Drag or Negative Traction of Geared-Down Supporting Propellers in the Downward Vertical Glide of a Helicopter
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.
System:
The UNT Digital Library
The Dynamometer Hub
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.
System:
The UNT Digital Library
Experience With Geared Propeller Drives for Aviation Engines
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.
System:
The UNT Digital Library
Recent Efforts and Experiments in the Construction of Aviation Engines
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]
System:
The UNT Digital Library
The Effect of Staggering a Biplane
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.
System:
The UNT Digital Library
Performance of a vane driven-gear pump
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 characteristics.
Date:
September 1921
Creator:
Heald, R. H.
System:
The UNT Digital Library
The Effect on Rudder Control of Slip Stream Body, and Ground Interference
"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.
System:
The UNT Digital Library
Report on the General Design of Commercial Aircraft
Given here are evaluations of six different European aircraft from the point of view of a passenger. The aircraft discussed are the DH 34, the Handley-Page W8B, the Farman Goliath, the Potez IX, the Spad 33 (Berline), and the Fokker F.III. The airplanes were evaluated with regard to seating comfort, ventilation, noise, seating arrangements, cabin doors, baggage accommodation, interior arrangement of cabins, pilot's position and communication with the pilot, pilot accommodations, view from the cabin, safety, and lavatory accommodations.
Date:
September 1922
Creator:
Warner, Edward P.
System:
The UNT Digital Library
Stresses Produced on an Airship Flying Through Gusty Air
"The stresses produced by gusts are proportional to the speed of the airship. At highest speed they are of the same range of magnitude as the stresses during the creation of a large dynamic lift" (p. 1).
Date:
September 1922
Creator:
Munk, Max M.
System:
The UNT Digital Library
Supplementary Report of Oil Scraper Piston Rings
Report presenting information based on the operating record of an engine subsequent to an overhaul related to an accident that made the results of a previous test invalid. The primary focus is on the performance of the oil-scraper piston rings in the engine and their ability to remove carbon deposits over the lifetime of the engine.
Date:
September 1922
Creator:
McDewell, H. S.
System:
The UNT Digital Library
Analysis of Dr. Schaffran's Propeller Model Tests
Note presenting an analysis of the propeller model tests of Dr. Schaffran. Only the thrust is examined. The results indicate that the thrust produced by three-blade and four-blade propellers follows the same laws as with two-blade propellers, and that all conclusions reached from Dr. Durand's tests can be upheld.
Date:
September 1923
Creator:
Munk, Max M.
System:
The UNT Digital Library
An impulse electric motor for driving recording instruments
The chief purpose in undertaking the development of this synchronous motor was the creation of a very small, compact power source, capable of driving the film drums of the recording aircraft instruments designed by the staff of the National Advisory Committee for Aeronautics.
Date:
September 1923
Creator:
Joachim, W. F.
System:
The UNT Digital Library
The Time Lag and Interval of Discharge With a Spring Actuated Fuel Injection Pump
Discussed here is research on a spring activated fuel pump for solid or airless injection with small, high speed internal combustion engines. The pump characteristics under investigation were the interval of fuel injection in terms of degrees of crank travel and in absolute time, the lag between the time the injection pump plunger begins its stroke and the appearance of the jet at the orifice, and the manner in which the fuel spray builds up to a maximum when the fuel valve is opened, and then diminishes.
Date:
September 1923
Creator:
Matthews, Robertson & Gardiner, A. W.
System:
The UNT Digital Library
Experimental Investigation of the Effect of an Oscillating Airstream (Katzmayr Effect) on the Characteristics of Airfoils
A series of experiments were conducted related to the action of an airstream oscillating vertically on supporting surfaces. The object of the experiments was to verify the very interesting results of Mr. Katzmayr, Director of the Vienna Aerodynamics Laboratory, and, if possible, to obtain more complete data on the effect of the amplitude and velocity of the oscillations of the airstream. The results obtained by Mr. Katzmayr are briefly summarized. The conduct of the numerous experiments to verify his results are described in detail. Experimental results are given in tabular and graphical form.
Date:
September 1924
Creator:
Toussaint; Kerneis & Girault
System:
The UNT Digital Library
Micarta propellers IV : technical methods of design
A description is given of the methods used in design of Micarta propellers. The most direct method for working out the design of a Micarta propeller is to start with the diameter and blade angles of a wooden propeller suited for a particular installation and then to apply one of the plan forms suitable for Micarta propellers. This allows one to obtain the corresponding blade widths and to then use these angles and blade widths for an aerodynamic analysis.
Date:
September 1924
Creator:
Caldwell, F. W. & Clay, N. S.
System:
The UNT Digital Library
A Short Method of Calculating Torsional Stresses in an Airplane Fuselage
"This report deals with an investigation carried out in the Civil Engineering Laboratory of the University of California, to determine the accuracy of existing methods of computing the stresses in an airplane fuselage when subjected to torsion, and to derive a simple approximate formula for the rapid calculation of these stresses. The formula is derived by using the customary least work equation and considering each bay separately" (p. 1).
Date:
September 1924
Creator:
Younger, John E.
System:
The UNT Digital Library
A Study of Static Stability of Airships
The first section deals with the theoretical side of statical stability of airships in general. The second section deals with preliminary tests of the model and experiments for the determination of effects due to change of tail area, aspect ratio, tail form, and tail thickness.
Date:
September 1924
Creator:
Rizzo, Frank
System:
The UNT Digital Library
Determination and Classification of the Aerodynamic Properties of Wing Sections
The following note, prepared for the NACA, contains several remarks on the possible improvement of the experimental determination of the aerodynamic properties of wing sections. It shows how errors of observation can subsequently be partially eliminated, and how the computation of the maxima or minima of aerodynamic characteristics can be much improved.
Date:
September 1925
Creator:
Munk, Max M.
System:
The UNT Digital Library
Propeller Scale Effect and Body Interference
"This note shows that the main part of the discrepancy between full flight propeller performance and the performance of models in a wind tunnel is due to a scale effect, and that a minor part is caused by body interference. Analyses are made of propeller performances on several standard airplanes, and the actual brake horsepower compared with the power as calculated from model test data. The calculated power is based on that absorbed by a wind tunnel propeller model which is geometrically similar to the full scale propeller and is operating under the same ratio of V/nD" (p. 1).
Date:
September 1925
Creator:
Weick, Fred E.
System:
The UNT Digital Library
Wind Tunnel Tests of Fuselages and Windshields
"The tests described herein were made in 1918, in the old four-foot wind tunnel at the Massachusetts Institute of Technology and at the request of the Engineering Division of the U.S. Army Air Service. The results were given circulation only in official circles at that time. The interest of the work appears sufficient to justify its wider distribution even at this very late date" (p. 1).
Date:
September 1925
Creator:
Warner, Edward P.
System:
The UNT Digital Library
The Drag of Airships I
Report presenting an examination of the drag of airships in order to design more functional aircraft and to obtain information for future research.
Date:
September 1926
Creator:
Havill, Clinton H.
System:
The UNT Digital Library
Test of a Model Propeller With Symmetrical Blade Sections
"This report, prepared at the request of NACA, gives the results of tests on a model propeller having blade sections with form of Gottingen airfoil no. 409. The model is shown to have a dynamic pitch practically equal to the nominal or geometrical pitch, and a somewhat higher efficiency but lower coefficient than would be expected of a propeller of more conventional sections" (p. 1).
Date:
September 1926
Creator:
Lesley, E. P.
System:
The UNT Digital Library
Airfoil lift with changing angle of attack
From Summary: "Tests have been made in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics to determine the effects of pitching oscillations upon the lift of an airfoil. It has been found that the lift of an airfoil, while pitching, is usually less than that which would exist at the same angle of attack in the stationary condition, although exceptions may occur when the lift is small or if the angle of attack is being rapidly reduced. It is also shown that the behavior of a pitching airfoil may be qualitatively explained on the basis of accepted aerodynamic theory."
Date:
September 1927
Creator:
Reid, Elliott G.
System:
The UNT Digital Library
Measurement of the Moments of Inertia of Full Scale Airplanes
"This paper contains a description of the method of measuring the moments of inertia of full scale airplanes as practiced by the National Advisory Committee for Aeronautics at the Langley Memorial Aeronautical Laboratory. The method, while not at all new, is published for the information and guidance of others who may desire to make similar measurements. The paper includes as an appendix the computations for the moments of inertia of 0-2 airplane" (p. 1).
Date:
September 1927
Creator:
Green, M. W.
System:
The UNT Digital Library