Bulletin presenting testing of a monocoque box with a stress-carrying door made and tested in torsion. The results indicate that if a stress-carrying door and its frame are made sufficiently heavy, the torsional stiffness of the box with the door can be made greater than the torsional stiffness of the box without the cut-out" (p. 1).

From General Analysis: "The purpose of part I of this paper is to show how the loading that gives the minimum induced energy loss can be obtained from rather elementary considerations and to present design charts from which such a plan form can be quickly obtained for any set of design conditions."

Report presenting two series of diagonal-tension beams with double uprights tested to destruction while strain measurements were being made at a large number of points. On the basis of a revised formula, more than 100 tests made by five manufacturers were analyzed.

Report presenting a study of the performance of bombers powered by two, four, and six 3000-horsepower engines supercharged to 35,000 feet. The performances are computed and are based on drag coefficients equal to the best obtained on modern airplanes and on weight estimates obtained from modern Army Air Forces airplanes. A chart is provided with the coordinates of power loading and wing loading noted so that all performances can be compared.

Report presenting air-flow surveys made in the region of the tail plane of a typical twin-engine tractor monoplane model with tail surfaces removed. The surveys were made with propellers removed and operating and for both cases included the conditions for flaps retracted and flaps deflected 50 degrees.

Report presenting methods for determining the jet-boundary corrections to the downwash behind models in rectangular wind tunnels. The methods take into account the tunnel dimensions, the type of jet, the span loading of the model, the geometric position of the wind and of the tail in the tunnel, the displacement of the wing wake, and the effect of the slipstream.

Report presenting investigations of a full-scale air-cooled aircraft-engine cylinder of 202-cubic-inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. Results regarding the maximum permissible engine performance, engine temperatures, and constant inlet-air pressure investigations are provided.

Report presenting samples of 17S-T and 24S-T aluminum alloys subjected to accelerated corrosion tests in which the corrosion period was established at 6 hours for samples that had been etched to produce a uniform surface. The results indicate the types of corrosion attack, which are described in standard terminology, and may form a basis for estimating the resistance of the material to corrosion by a comparison of the relative depth and frequency of the corrosive attacks.

Report presenting an investigation to determine whether the difference in the spanwise loading of the two types of aircraft were responsible for the differences in spin characteristics, particularly in regards to angle of attack.

Report presenting an investigation conducted in the 19-foot pressure tunnel to determine the aerodynamic effects of several arrangements of external auxiliary fuselage and wing tanks of large fuel capacity on a fighter-type airplane. The rectangular tank arrangement of 350-gallon fuel capacity has the greatest adverse aerodynamic effect on the airplane and is the least desirable of all the configurations tested.

Report presenting the results of spin-tunnel testing of 65 models indicating that when a single-engine type airplane was simulated with mass distributed along the fuselage, the rudder was the predominant control for recovery. The primary focus of this investigation is to determine the spinning characteristics of the airplane and to develop a useful criterion for predicting the optimum control manipulation for recovery.

Supplement using data from a previous report to show the cargo that can be carried at various ranges, pounds of cargo that can be carried per pound of fuel, and other graphs to simplify the problem of determining which cargo can be carried at any range. The assumptions, parameters, and equations from the original report are carried over in the supplement.

Report presenting aerodynamic tests of a 300-pound M-31 demolition bomb. Force tests at a range of angles of attack were made at Mach number 0.725, which corresponds to a speed of 810 feet per second at sea level. Results regard the drag, lift, and pitching moment are provided.

Results are presented of tests of two specimens tested to study the effect of normal pressure on the critical compressive stress for thin curved sheets. These specimens are designated by their respective rib spacings of 10 inches and 30 inches. The relationship between compressive stress and normal pressure at which buckles disappeared is independent of whether the buckles were made to disappear by increase of normal pressure or decrease of compressive stress. (author).