Report presenting tests of the low-speed lateral-control characteristics of an observation airplane with ailerons and spoilers in combination and with the spoilers disconnected and the ailerons used alone with various amounts of droop. The results indicated that in unstalled flight at low speeds and with flaps deflected, little or no aerodynamic benefit was derived by changing the lateral-control system from the aileron and spoiler combination to a normal aileron installation either with or without aileron droop.

Report discusses the results of an investigation into a full-span retractable flap in combination with a full-span plain and internally balanced ailerons on a tapered wing of a typical fighter airplane.The flap was designed to improve lateral control during high lifts for landing and take-off. The effects on the maximum life coefficient, aileron effectiveness, estimated rates of roll, and stick forces are provided.

Report presenting a report illustrated by photographs and vibration records on the failure of the P-47 rudder in the high-speed tunnel at a true speed of 468 miles per hour and a density corresponding to 9000 feet altitude. The fin-rudder unit was tested as being at least representative of the tail design of the P-47 airplane.

Report presenting tests made on an NACA 23012 airfoil fitted with a 20-percent-chord, true-contour aileron with 35-percent-chord, extreme blunt-nose balance. The primary purpose of the investigation was to determine the variation of the aerodynamic characteristics of this type of aileron with airspeed; the effect of variations of gap width and balance-nose radii was also investigated. Results regarding hinge moments, lift, and pitching-moment coefficients are provided.

Report presenting thermal and static pressure-drop performance data on three fluted-type heat exchangers. Two of the heaters used corrugated surfaces along the fluid passages and the third one was constructed with non-corrugated surfaces. Results regarding a comparison of results on the noncorrugated heater using two different air shrouds, heat transfer, isothermal static pressure drop, nonisothermal static pressure drop, and heater surface temperatures are provided.

"The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing movements of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested" (p. 1).

Report presenting an investigation to determine methods for improving the cooling of air-cooled engine cylinders by means of baffle modifications. Testing was conducted using a Pratt & Whitney R-1830-43 engine mounted on a ground test stand. Results regarding temperature data for variations in atmospheric conditions, temperature measurements at various points along the cylinder, and some of the implied effects of baffle modifications are provided.

Report presenting a thermal ice-prevention system for the B-17F airplane. The report includes a description of the design, an outline of the design, analysis, and a presentation and discussion of flight-test thermal data secured under non-icing conditions. The basic idea of the design was to raise the temperature of the surfaces to be protected from ice formations by subjecting the inner faces to a stream of heated air.

Report presenting a program of tests on engine induction system de-icing by means of de-icing fluids and heated air. Several types of de-icing fluids were injected at several different locations and at various fluid flow rates were explored.

Report presenting testing of the flutter characteristics of the SB2U model conducted after the model had been modified to lower its flutter speed. The model was tested to destruction and the flutter speed was measured throughout.

Report presenting a full-size single-engine pursuit airplane, with wing tips cut off, tested in the 16-foot wind tunnel. The purpose was to find means for eliminating an extreme rumble which occurred at high speeds when the radiator air-duct-exit openings were small. Results regarding rumble, cooling air, and drag are provided.

Report presenting a method for determining the damping moment in yawing for tapered wings with partial-span flaps. Charts are given for untwisted wings with various taper ratios, aspect ratios, and center-span flaps. Theoretical and experimental results are provided.

"The data presented in this report are part of a general program to determine the effects of xylidines on the knock-limited performance of currently used aviation fuels" (p. 2).

Report presenting two blending equations that have been derived from an analysis based on certain assumptions relative to the cause of fuel knock. The main purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends.

Report presenting testing to determine the effect of xylidines on the load-carrying capacity of aircraft-engine oil in several test devices. Lubricating oil and lubricating oil with xylidines added was tested in four different testing machines. In all of the experiments, adding the xylidines made the oil a poorer lubricant in the boundary region of lubrication, where metal-to-metal contact occurs.

Report presenting tests to determine the effect of xylidines on the stability of an aircraft-engine lubricating oil. The Indiana oxidation test and measurements of the oxygen absorption rate of the oil samples were performed on Navy 1120 oil, Navy 1120 oil plus 0.5 percent by weight of xylidines, and Navy 1120 oil used in piston-ring-sticking tests both with and without xylidines. Results regarding the Indiana oxidation test, the Davis oxidation test, the automatic oil-oxidation apparatus, and a laboratory inspection are provided.

"An experimental study was made to determine the effect of artificial aging on the tensile properties of alclad 24S-T and 24S-T aluminum-alloy sheet material. The results of the tests show that certain combinations of aging time and temperature cause a marked increase in the yield strength and a small increase in the ultimate strength; these increases are accompanied by a very large decrease in elongation. A curve is presented that shows the maximum yield strengths that can be obtained by aging this material at various combinations of time and temperature" (p. 1).