Report discussing the knock-limited performance of blends of triptane and 28-R fuel in an F-4 engine at three sets of conditions and three compression ratios. The knock limits of the triptane blends were more sensitive to compression ratio than the 28-R fuel, and the sensitivities of the blends increased as the severity of other engine conditions increased.

Report presenting tests to investigate the effect of 2-percent additions of nine aromatic amines on the knock-limited performance of AN-N-28 (28-R) fuel. The results of the testing of antiknock effectivneess of the 27 aromatic amines obtained to date in the program are also summarized.

Report discussing tests on the effect of 2-percent additions of 13 aromatic amines on the knock-limited performance of 28-R fuel in a CFR engine. The amines tested gave good rich mixture response at standard F-4 operating conditions, but were sensitive to engine severity at lean fuel-air ratios.

Report presenting wind tunnel tests of NACA 65(216)-420 and 66(218)-420 airfoils at speeds up to and slightly above the critical. Section coefficients of lift, drag, and pitching-moment and extensive pressure-distribution data are presented. The critical speed for these airfoils at their design life coefficient of 0.4 is shown to be about 460 miles per hour at seal level and about 415 miles per hour at 25,000 feet altitude.

Report presenting testing in the 19-foot pressure tunnel of a scale semispan model of the XTB2D-1 airplane wing and fuselage combination. The purpose of the investigation was to determine the optimum position of the double-slotted flap, the characteristics of the full-span flaps at various deflections in their fully extended position, the effectiveness of deflecting the full-span flaps to small positive angles as a camber changing feature, the stalling characteristics of the wing, and the effectiveness of the flap as a brake when deflected to negative angles.

Report presenting tests of airplane models that included investigations to determine the longitudinal stability and control, effects of various constituent parts or their modification on longitudinal stability and control, critical speed, and distribution of wing load. Some of the changes made in attempts to improve longitudinal control and to increase critical speed included auxiliary control flaps on the lower surface of the wing, revision of the windshield, increase in dimensions of outboard nacelles, and alteration in profile of wing leading edge.

Report presenting tests made in order to determine the differences in high-speed aerodynamic characteristics between models of a four-engine transport airplane and a similar bomber airplane. The main conclusion found is that the critical Mach number of the transport model is about 0.05 less than that of the bomber model.

Report discussing the mutual interference effects of tail surfaces and a stern propeller on a model of the XB-42.The main focus was to determine the effect of tail surface-propeller spacing upon the periodic tail surface loading coincident with propeller blade passage.

Report discussing the cooling characteristics of a 14-cylinder double-row radial air-cooled engine in a four-engine airplane. The effects of charge-air flow, cooling-air pressure drop, and fuel-air ratio on the cooling characteristics were measured separately. The cooling equation, rear middle-barrel temperature, cooling-limited manifold pressure, and maximum cruising power versus temperature-limited power are described.

Report presenting tests to investigate the effect of 2-percent additions of 11 aromatic amines on the knock-limited performance of AN-F-28 fuel. A total of 48 aromatic amines are being prepared for knock tests. Results regarding the knock-limited performance data, antiknock effectiveness, and knock-limited powers are provided.

Report presenting tests of the Northrop MX-334 airplane in the full-scale tunnel. The results are of particular interest since the MX-334 is an all-wing glider-type airplane without a conventional fuselage or vertical surfaces. The primary purpose was to obtain sufficient data with which to determine the longitudinal and lateral stability and control characteristics of the airplane.

Report presenting testing in the two-dimensional low-turbulence tunnels on a 24-inch-chord model of the NACA 66(215)-116 a = 0.6 airfoil with a 0.25-chord slotted flap. The optimum flap pivot positions were found for three different conditions. The conditions were determined from a consideration of the landing, take-off, and strafing requirements of the airplane.

Report presenting flight measurements of the pressures on the horizontal tail surfaces of a typical propeller-driven pursuit airplane during stalled pull-outs at high Mach number. Unit loads measured on the stabilizer at safe maneuvering limits were not only considerably in excess of the design unit loads, but also occurred in a direction opposite to the design loads. Revision of the tail-load design requirements and manner of specifying safe maneuverability limits to pilots appears necessary.

Report presenting a series of tests on the Brewster XSBA-1 airplane to determine the effects of various tail modifications. Some of the modifications include variations of the chord of the elevator and rudder while the span and total area of the surfaces are kept constant and variations of the total area of the vertical tail surface. Results regarding the longitudinal stability and control and lateral stability and control are provided.

Report discussing testing of the Douglas A-26B to determine the longitudinal stability and control characteristics. Information about the elevator, stick-fixed and stick-free stability, center of gravity, and flap effects are described.

The effects of jet-motor operation on the stability and control characteristics of two fighter-type airplanes as determined by wind-tunnel tests of 1/5-scale models are presented. It is shown that the action of the jets is to cause a small loss in stick-fixed stability which is predictable from known theories.

Report presenting an investigation of the cooling of a Franklin 6-AC-29S horizontally opposed cylinder air-cooled engine installed in a Fleetwings model 33 trainer. The cowling on the airplane did not provide satisfactory cooling, but several alterations were tested, including with cylinder baffles. Results regarding engine cooling, aerodynamics of the cowling installation, and predicted versus actual cowling performance are provided.

Report presenting an investigation conducted with the propeller cuffs and spinner removed to determine their effect in flight on the pressure recovery of the cooling-air flow. Curves are presented to compare the pressure and temperature distribution over the front row of cylinders for flights with and without cuffs and spinner.

"This report contains the results of tests of a full-scale semispan horizontal tail plane of a bomber airplane. The effects of fabric distortion on the aerodynamic characteristics of the elevator are determined by comparing the aerodynamic characteristics of a fabric-covered elevator with those of a metal-covered elevator. In addition, the results of cutting holes in the balance seal, the effect of fixing transition, the tab effectiveness both sealed and unsealed, and the section drag of this tail plane are presented" (p. 1).

"F-3 and F-4 knock data are presented for blends of 0, 20, 40, 60, and 80 percent by volume of triptane in 28-R reference fuel plus approximately 4.6 ml TEL per gallon in the final blends. For comparison of knock-limited performance, 28-R reference fuel containing 2.7 percent by volume of xylidines and leaded to 6 ml TEL per gallon is included. In order to provide information on temperature sensitivities, two sets of modified conditions were used in addition to the standard F-4 engine conditions" (p. 1).

Report presenting tests made with a dynamic model of the Army B-26 airplane to determine its behavior when landed on water. Results regarding the general behavior, effect of flaps, effect of landing attitude and speed, tests with undamaged model, tests with simulated damage, tests with propellers, vertical decelerations, and effect of weight are provided.

Results are presented for tests of two wings, an NACA 230-series wing and a highly-cambered NACA 66-series wing on a twin-engine pursuit airplane. Auxiliary control flaps were tested in combinations with each wing. Data showing comparison of high-speed aerodynamic characteristics of the model when equipped with each wing, the effect of the auxiliary control flaps on aerodynamic characteristics, and elevator effectiveness for the model with the 66-series wing are presented. High-speed aerodynamic characteristics of the model were improved with the 66-series wing.

Report presenting a series of outdoor tests to determine the static-thrust and torque characteristics of single- and dual-rotating propellers for use in aircraft propeller design and in take-off performance estimation.

Report presenting testing to determine which of three spinner-diffuser designs on an NACA cowling was the most effective in cooling a Pratt & Whitney R-2800 engine installation. The results of pressure-distribution studies in front of and behind each bank of cylinders are presented for a wide range of propeller-operating conditions.