This report describes the development of airplane characteristics since the war and indicates the direction development should take in the immediate future. Some of the major topics include: the behavior of an airplane about its lateral, vertical, and longitudinal axes. Behavior at large angles of attack and landing characteristics are also included.

The present report describes many cases of airplanes being struck by lightning and the measures that can be taken to minimize damage to them. The data indicates that the hazard to airplanes from lightning is overestimated and that dangers can be minimized by appropriate weather forecasts and training of the pilots.

This report presents a method for computing the flight performance of an autogiro at high speed, the velocity component along the blades being accounted for by calculation of the profile drag and the equation for zero torque.

From Introduction: "This report gives the results of wind-tunnel tests with a seaplane model as a contribution to the solution of the aerodynamic problems."

As a result of previous reports, it was endeavored to obtain, along with the truest possible comprehension of the course of thrust, a complete, simple and clear formula for the whole take-off distance up to a certain altitude, which shall give the correct relative weight to all the factors.

"Various methods have been proposed for determining the inherent stresses in structural components by disturbing their stress equilibrium through a mechanical device and measuring the resulting deformations. The methods used have disadvantages because they can be used only with specially shaped pieces (those with round or rectangular cross sections), that every form of test piece requires another kind of injury and hence of calculation, and the tested parts are rendered useless. The new test method, which seeks to eliminate these disadvantages, is likewise based on a disturbance of the equilibrium of forces, and indeed by drilling a hole which, however, is so small that the part can be used again" (p. 1).

"A number of German airplanes have a gap between elevator and stabilizer. The effect of this open space is not generally known, although English wind-tunnel experiments have shown that even a very small gap exerts a profound influence on the elevator action. The purpose of the present free-flight measurements is to ascertain whether fairing over the gap would actually result in an appreciable improvement" (p. 1).

"Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example" (p. 1).

"The static stresses of airplane parts, the magnitude of which can be determined with the aid of static load assumptions, are mostly superposed by dynamic stresses, the magnitude of which has been but little explored. The object of the present investigation is to show how the strength of airplane parts can best be tested with respect to dynamic stresses with and without superposed static loading, and to what extent the dynamic strength of the parts depends on their structural design. Experimental apparatus and evaluation methods were developed and tried for the execution of vibration-strength tests with entire structural parts both with and without superposed static loading" (p. 1).

This report describes a device for arbitrary enlargement of the gliding angle of airplanes, especially of such with flat gliding angle and difficult landing characteristics. The D.V.L. gliding angle control (design, Hubner) permits a local interruption of the lift distribution along the span and consequently an increased induced drag. The mechanism comprises two wing rudders operated by lever from the pilot's cockpit. Said rudders are fitted on the top side of the wing near the leading edge. The displacement of these rudders results in a separation of the air flow on the top side of the wing.

The quantity of air which the disk area described by propeller blades travels through, is accelerated rearward conformably to the momentum of the forces acting on the propeller. The accelerated air mass forms behind the propeller the so-called slipstream, in which among others, the mean velocity of advance is increased. If the propeller axis slopes toward the relative flight direction, the slipstream direction likewise changes, i.e., it sets up a downwash behind the propeller.

This paper presents the characteristics of floats submitted to the test committee and the tests performed on them.

The historical development of the rules for structural strength of aircraft in the leading countries is traced from the beginning of flight to date. The term "factor of safety" is critically analyzed; its replacement by probability considerations has been considered desirable.

Load factors and loading conditions are presented for Germany, England, and the United States. Results of tests are presented and loading conditions are presented under various stress categories like freight, commercial, aerobatics, and training.

Load factors and loading conditions are presented for German aircraft. Loading conditions under various stress factors are presented along with a breakdown of individual aircraft components such as landing gear, wings, etc.

This report presents the results of a series of free-jet measurements to determine the pure frictional resistance of a cylinder from the difference between total resistance and pressure at Reynolds Numbers 5,000 to 40,700. The skin friction is 5 percent of the total resistance at Re = 5,000, and had dropped to 2 percent at Re = 40,000, which supports Thom's theory.

"Aerodynamic considerations led us, not long ago, to investigate a device which seemed to promise a contribution to the problem of reducing the landing speed of an airplane. We have subsequently learned that similar devices had already been proposed and investigated by others, but it seems advisable, nevertheless, to report our results. The problem is to create, in landing, a region of turbulence on the lower side of the wing near the trailing edge by some obstacle to the air flow" (p. 1).

Progressive application of the Kutta-Joukowsky theorem to the relationship between airfoil lift and circulation affords a number of formulas concerning the conduct of vortex systems. The application of this line of reasoning to several problems of airfoil theory yields an insight into many hitherto little observed relations. This report is confined to plane flow, hence all vortex filaments are straight and mutually parallel (perpendicular to the plane of flow).

This report presents a history of the Schneider trophy race with special emphasis of England's win in the 1931 race. Lift and drag are reported on and discussed extensively.

"In the use of piezo-quartz indicators for high-speed automobile engines, the interpretation of pressure-time diagrams made by an oscillograph offers certain difficulties. On the one hand, the scale of the pressure amplitudes is not always the same under all conditions, while, on the other hand, the atmospheric zero line may be shifted from its correct position in the oscillogram. These facts make necessary to verify the readings of the quartz indicators by direct calibration before and after each series of tests and, on the basis of the results, to determine the scale for the oscillograms" (p. 1).

"On various low-wing monoplanes the horizontal tail surfaces flutter in flight at large angles of attack and occasionally in curvilinear flight. This flutter leads to torsional vibrations of the rear end of the fuselage, as manifested by vibrations of the control stick. According to the earlier DVL investigations tail flutter is due to the influence, on horizontal tail surfaces, of eddies or vortices shed at large angles of attack by the upper surface of the wing root. The cause of tail flutter on a low-wing monoplane and the means of preventing it are investigated in the present report" (p. 1).

Memorandum presenting two reports. One is a description of the 1932 Rhön Soaring Contest and some of the problems encountered by the aircraft in the contest. The other is a description of films of cloud formations that were presented at the same contest.

"The static longitudinal stability of an airplane with locked elevator is usually determined by analysis and model tests. The present report proposes to supply the results of such measurements. The method consisted of recording the dynamic pressure versus elevator displacement at different center-of-gravity positions in unaccelerated flight" (p. 1).

Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.