The development of German Army airplanes during the war (open access)

The development of German Army airplanes during the war

From Summary: "The author, who was a captain of the Reserves in the Technical Department of the Aviation Division (Board of Airplane Experts) during the war, shows what means were taken for the creation of new airplane types and what tests were employed for trying out their flying properties, capacities and structural reliability. The principal representative types of each of the classes of airplanes are described and the characteristics of the important structural parts are discussed. Data regarding the number of airplanes at the front and the flying efficiency of the various classes of airplanes are given."
Date: June 1921
Creator: Hoff, Wilhelm
System: The UNT Digital Library
Progress Made in the Construction of Giant Airplanes in Germany During the War (open access)

Progress Made in the Construction of Giant Airplanes in Germany During the War

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.
System: The UNT Digital Library
Airplanes in horizontal curvilinear flight (open access)

Airplanes in horizontal curvilinear flight

The report discussing single and two-seater airplanes as well as larger airplanes.
Date: January 1924
Creator: Kann, Heinrich
System: The UNT Digital Library
Investigation of Boundary-layer Control to Improve the Lift and Drag Characteristics of the NACA 65â‚‚-415 Airfoil Section with Double Slotted and Plain Flaps (open access)

Investigation of Boundary-layer Control to Improve the Lift and Drag Characteristics of the NACA 65â‚‚-415 Airfoil Section with Double Slotted and Plain Flaps

From summary: "A two-dimensional wind-tunnel investigation has been made of the relative effectiveness of two methods of boundary-layer control in increasing the maximum lift coefficient of an NACA 652-415 airfoil section."
Date: August 1950
Creator: Horton, Elmer A.; Racisz, Stanley Frank & Paradiso, Nicholas J.
System: The UNT Digital Library
Practical Method for Balancing Airplane Moments (open access)

Practical Method for Balancing Airplane Moments

"The present contribution is the sequel to a paper written by Messrs. R. Fuchs, L. Hopf, and H. Hamburger, and proposes to show that the methods therein contained can be practically utilized in computations. Furthermore, the calculations leading up to the diagram of moments for three airplanes, whose performance in war service gave reason for complaint, are analyzed. Finally, it is shown what conclusions can be drawn from the diagram of moments with regard to the defects in these planes and what steps may be taken to remedy them" (p. 1).
Date: February 1924
Creator: Hamburger, H.
System: The UNT Digital Library
The Problem of the Turbo-Compressor (open access)

The Problem of the Turbo-Compressor

"In terminating the study of the adaptation of the engine to the airplane, we will examine the problem of the turbo-compressor, the first realization of which dates from the war; this will form an addition to the indications already given on supercharging at various altitudes. This subject is of great importance for the application of the turbo-compressor worked by the exhaust gases. Assuming that the increase of pressure in the admission manifold is the same in both cases, the pressure in the exhaust manifold would be greater in the case in which the compressor is worked by the exhaust gas and there would result a certain reduction of engine power which we must be able to calculate" (p. 1).
Date: August 1920
Creator: Devillers, René
System: The UNT Digital Library
Recent Efforts and Experiments in the Construction of Aviation Engines (open access)

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
Steam Power Plants in Aircraft (open access)

Steam Power Plants in Aircraft

"The employment of steam power plants in aircraft has been frequently proposed. Arguments pro and con have appeared in many journals. It is the purpose of this paper to make a brief analysis of the proposal from the broad general viewpoint of aircraft power plants. Any such analysis may be general or detailed" (p. 1).
Date: June 1926
Creator: Wilson, E. E.
System: The UNT Digital Library
Micarta Propellers 1: Materials (open access)

Micarta Propellers 1: Materials

Here, values for tension, compression edgewise of laminations, and transverse flatwise of laminations are given for Micarta made with various kinds of sheet material. The corresponding values for white oak are given for comparison. It was found by destructive and service tests that Micarta made with a good grade of cotton duck will give satisfactory service with most designs.
Date: August 1924
Creator: Caldwell, F. W. & Clay, N. S.
System: The UNT Digital Library
Micarta Propellers 2: Method of Construction (open access)

Micarta Propellers 2: Method of Construction

The methods used in manufacturing Micarta propellers differ considerably from those employed with wood propellers on account of the hardness of the materials. The propellers must be formed accurately to size in a mold and afterwards balanced without the customary trimming of the material from the tips. Described here are the pressing and molding processes, filing, boring, balancing, and curing.
Date: August 1924
Creator: Caldwell, F. W. & Clay, N. S.
System: The UNT Digital Library
Methods of Visually Determining the Air Flow Around Airplanes (open access)

Methods of Visually Determining the Air Flow Around Airplanes

"This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods" (p. 1).
Date: July 1932
Creator: Gough, Melvin N. & Johnson, Ernest
System: The UNT Digital Library
Micarta propellers IV : technical methods of design (open access)

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
Marine Exposure Tests on Stainless Steel Sheet (open access)

Marine Exposure Tests on Stainless Steel Sheet

Note presenting tidewater and weather-exposure tests on metals used in aircraft. Three distinct research projects were included: aluminum-rich alloys, magnesium-rich alloys, and stainless steels. This paper is a final report on the corrosion tests of stainless steel sheets included in the marine exposure program from 1938 to 1945.
Date: February 1947
Creator: Mutchler, Willard
System: The UNT Digital Library
Micarta Propellers III: General Description of the Design (open access)

Micarta Propellers III: General Description of the Design

The design of propellers made of Micarta is discussed. The advantages of the material are noted, especially as compared with wood. The design changes necessitated by the use of Micarta are discussed with reference to the hub boss, the narrowing of the blade tips, the thinning of the blades, the angles of the leading and trailing edges, and the adjustment of the pitch. Results of flight tests show that the Micarta propeller gave a top speed of 2 miles per hour more than the wooden propeller while turning about 120 r.p.m slower, with about the same rate of climb.
Date: August 1924
Creator: Caldwell, F. W. & Clay, N. S.
System: The UNT Digital Library
Structural Safety During Curved Flight (open access)

Structural Safety During Curved Flight

Note presenting an exploration of aircraft safety during curved flight, which leads to more stress on the wings than other types of flight.
Date: August 1922
Creator: Rohrbach, Adolf
System: The UNT Digital Library
Theory of the Slotted Wing (open access)

Theory of the Slotted Wing

Report presenting information regarding the use of slots in an airplane wing to considerably increase the lift and make it possible to operate the wing at higher angles of attack.
Date: June 1922
Creator: Betz, A.
System: The UNT Digital Library
The Dynamometer Hub (open access)

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
The Drag of Airships I (open access)

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
Experiments With Slotted Wings (open access)

Experiments With Slotted Wings

Note presenting an investigation of various aspects of slotted wings, including some theoretical and experimental results and characteristics of certain slotted wings currently in production.
Date: November 1921
Creator: Lachmann, G.
System: The UNT Digital Library
General Consideration of Problems in Compressible Flow Using the Hodograph Method (open access)

General Consideration of Problems in Compressible Flow Using the Hodograph Method

Report presenting an investigation of the hodograph method as it is applied in general to the problem of compressible flow.
Date: January 1952
Creator: Chang, Chieh-Chien
System: The UNT Digital Library
Variation in the Number of Revolutions of Air Propellers (open access)

Variation in the Number of Revolutions of Air Propellers

Note describing the variation in the number of revolutions per minute and provides simple formulas that allow for advanced calculation to be made of the variation of propeller speed with variation of one or more dimensions of the propeller and allow the necessary corrections to be applied.
Date: March 1923
Creator: Achenbach, W.
System: The UNT Digital Library
Notes on Specifications for French Airplane Competitions (open access)

Notes on Specifications for French Airplane Competitions

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.
System: The UNT Digital Library
Note on the Resistance of Polished Cylinders (and Cylindrical Wires) With Generatrices Perpendicular to the Airstream (open access)

Note on the Resistance of Polished Cylinders (and Cylindrical Wires) With Generatrices Perpendicular to the Airstream

Report presenting a review of currently published documents regarding the resistance of polished cylinders with generators perpendicular to the airstream. The discrepancies between these various studies are pointed out.
Date: February 1921
Creator: Toussaint, A.
System: The UNT Digital Library
Measuring an Airplane's True Speed in Flight Testing (open access)

Measuring an Airplane's True Speed in Flight Testing

Note giving an overview of five distinct methods shown for timing an airplane over a given distance and measuring the wind velocity, which provides the true speed of the airplane.
Date: April 1923
Creator: Brown, W. G.
System: The UNT Digital Library