A historical sketch of duralumin is presented, especially in regards to its manufacture by various countries. The properties of duralumin are discussed and strength characteristics listed. Increasing the hardness of duralumin by tempering is discussed as well as the uses of the metal.

From Summary: "This report presents a concise survey of the measurement of air speed and ground speed on board aircraft. Special attention is paid to the Pitot-static air-speed meter which is the standard in the United States for airplanes. A bibliography on air-speed measurement concludes the report."

Report discussing about 400 references pertaining to the hydrodynamic design of seaplanes have been compiled, and the information is presented in the form of abstracts classified under six main headings.

The economic costs and benefits of speed on airship traffic are calculated and different factors are considered.

This report is a recounting of the German investigation of the crash of a commercial Junkers F 13 ge in England. The English report is examined and compared with the German interpretation of the accident.

The present state of the problem of materials in airplane construction is studied on the basis of data giving the principal characteristics of different materials and showing how they affect the form of airplane parts.

From Introduction: "This bulletin is the seventh in this series of petroleum bibliographies published by the Bureau of Mines, Bulletins 149, 165, 180, 189, 216, and 220 being complications for the years 1915, 1916, 1917, 1918, 1919-20, and 1921, respectively. In this bulletin the same general plan of classification of references has been followed, but several additions have been made."

Goldbeater's skin, which is the prepared outside membrane of the large intestine of an ox, is examined as a balloon fabric and details of how goldbeater's skin is prepared for use are provided. The construction techniques employed by Germany, France, and England are all discussed.

Definitive history of the United States National Bureau of Standards.

Major psychological findings and data in the field of the legibility of alphanumeric characters and other symbols.

The purpose of this paper is to summarize the present status of the problem of mooring airships. Mooring with one, two and even three cables are all discussed.

Discussed here are results already achieved with sonic altimeters in light of the theoretical possibilities of such instruments. From the information gained in this investigation, a procedure is outlined to determine whether or not a further development program is justified by the value of the sonic altimeter as an aircraft instrument. The information available in the literature is reviewed and condensed into a summary of sonic altimeter developments. Various methods of receiving the echo and timing the interval between the signal and the echo are considered. A theoretical discussion is given of sonic altimeter errors due to uncertainties in timing, variations in sound velocity, aircraft speed, location of the sending and receiving units, and inclinations of the flight path with respect to the ground surface. Plots are included which summarize the results in each case. An analysis is given of the effect of an inclined flight path on the frequency of the echo. A brief study of the acoustical phases of the sonic altimeter problem is carried through. The results of this analysis are used to predict approximately the maximum operating altitudes of a reasonably designed sonic altimeter under very good and very bad conditions. A final comparison is made …

This report outlines briefly the methods of aerial navigation which have been developed during the past few years, with a description of the different instruments used. Dead reckoning, the most universal method of aerial navigation, is first discussed. Then follows an outline of the principles of navigation by astronomical observation; a discussion of the practical use of natural horizons, such as sea, land, and cloud, in making extant observations; the use of artificial horizons, including the bubble, pendulum, and gyroscopic types. A description is given of the recent development of the radio direction finder and its application to navigation.

"This work proposes to sketch, in broad outline, the status of airship construction in the various countries, at a time when commerce over great distances might be finally opened up to the airship through the performances of the "Graf Zeppelin." After a short historical review, a survey of the most important rigid and semirigid airships built since 1925, their differences and special problems, is made. In more detailed treatment, the framing construction of the more recent rigid airships and some especially interesting structural questions are investigated" (p. 1).

The causes of the destruction of the Dixmude are discussed and some conclusions are drawn. The author believes a gasoline fire instead of a lightning strike was probably responsible, but the public believes otherwise.

"This article is based on the experience of the Schute-Lanz Airship Company in light construction. The object is to stimulate the employment of these methods in other fields of industry" (p. 1).

"Preliminary information on the complex subject of the fatigue strength of fabricated structural members for aircraft is presented in the test results obtained on several different types of airship girders subjected to axial tension and compression in a resonance fatigue machine. A description of this machine as well as numerous photographs of the fatigue failures are given. There is also presented an extended bibliography on the subject of fatigue strength" (p. 1).

We propose to make a study of the difficulties in using stressed coverings and their appropriate solutions. Fatigue and buckling are also discussed.

From Introduction: "Examples of the use of the derived heat-of-fusion values in the application of thermodynamics to problems concerning metallurgical practice are not given here, but the reader is referred to the textbook of Lewis and Randall (454), in which the methods and types of calculations are adequately portrayed, and to the papers of Maier (469, 470, 471), in which the application of thermodynamic methods to various problems of metallurgical interest has been illustrated and discussed."

Report issued by the Bureau of Mines containing a compilation of four previously printed Bulletins discussing thermodynamics and inorganic substances. The four reprints included are bulletins 383, 384, 393, and 406, and are each printed in full. This report includes tables.

Report presenting suggestions for the standardization of the study of aerodynamics in laboratories in the United States and Europe. A report by each of the different scientists, all of whom are working in a variety of different labs and countries, is provided, and each discusses the progress made in their respective labs and their suggestions for standardization and progress in the field.

Many treatises in regard to construction of airship sheds are lacking in data on air currents, for which reason this phase of the problem will be here thoroughly discussed in connection with the accompanying photographs of currents.

Memorandum presenting a description of the development of the mooring mast and how it contributes to the technique of landing large airships. Some of its fundamental requirements and how it can factor into safe landings are provided.

"Results of measurements on a shrouded propeller are given. The propeller is designed for the high ratio of advance and high thrust loading. The effect of the shape of propeller and shroud upon the aerodynamic coefficients of the propulsion unit can be seen from the results" (p. 1).