Report presenting an investigation to measure the flying qualities of a high-performance personal-owner airplane to investigate the possible causes of instrument flying accidents with that type of aircraft. Testing indicated that the lack of aerodynamic stall warning and rapid roll-off at the stall could contribute to stall-spin accidents with high-performance personal-owner aircraft. Results regarding the handling qualities and the control under instrument flying conditions are provided.

Buffet boundaries, buffeting-load increments for the stabilizers and elevators, and buffeting bending-moment increments for the stabilizers and wings as measured in gradual maneuvers for a jet-powered bomber airplane are presented. The buffeting-load increments were determined from strain-gage measurements at the roots or hinge supports of the various surfaces considered. The Mach numbers of the tests ranged from 0.19 to 0.78 at altitudes close to 30,000 feet. The predominant buffet frequencies were close to the natural frequencies of the structural components. The buffeting-load data, when extrapolated to low-altitude conditions, indicated loads on the elevators and stabilizers near the design limit loads. When the airplane was held in buffeting, the load increments were larger than when recovery was made immediately.

Report presenting the results of an experimental investigation of the downwash and longitudinal stability characteristics of a semispan, triangular-wing airplane model with a horizontal tail. Lift, drag, and pitching-moment data re presented for the wing-fuselage combination. Results indicated that the model with the tail on or below the wing-chord plane possessed satisfactory stability characteristics throughout the test range of lift coefficient.

From Summary: "Experimental force, moment, and center-of-pressure variations for a large number of bodies of revolution have been compared with the calculated characteristics based on the approximate theory developed in NACA-RM-A9I26. The bodies varied in fineness ratio from 4.5 to 21.1, from blunt unboattailed bodies to airship hulls, and the experimental results are given for widely varying Mach number ranges of angle of attack. It is shown that the lift and drag characteristics are fairly accurately predicted by the theory but that the actual center of pressure is more rearward than the theory indicates."

Memorandum presenting flight tests conducted on two straight-wing jet airplanes of generally similar configuration, one exhibiting a diving tendency and the other a climbing tendency, in order to investigate the cause for the particular type of behavior of each airplane at high Mach numbers. The results showed that the diving tendency experienced by the one airplane was due to the predominant effect of an increased angle of attack of the horizontal tail.

From Summary: "Flight tests were conducted on a straight-wing fighter-type jet airplane to investigate the lateral-control characteristics associated with a wing-dropping tendency encountered at high subsonic Mach numbers. The chief factors found to account directly for the wing-dropping tendency were a progressive reduction in aileron-control effectiveness with increasing Mach number, and an increase in effective dihedral above a Mach number of 0.8 which made the lateral trim particularly sensitive to small changes in sideslip angle."

The altitude-ignition limits of a condenser-discharge ignition system installed on a turbojet engine were determined at a flight Mach number of 0.6 using 1.1-pound Reid vapor pressure fuel. Ignition was possible up to an altitude of 55,000 feet with 4.8 joules per spark and 6 sparks per second.

Effects of air-cooling turbine rotor blades on performance of a turbojet engine were calculated for a range of altitudes from sea level to 40,000 feet and a range of coolant flows up to 3 percent of compressor air flow, for two conditions of coolant bleed from the compressor. Bleeding at required coolant pressure resulted in a sea-level thrust reduction approximately twice the percentage coolant flow and in an increase in specific fuel consumption approximately equal to percentage coolant flow. For any fixed value of coolant flow ratio the percentage thrust reduction and percentage increase in specific fuel consumption decreased with altitude. Bleeding coolant at the compressor discharge resulted in an additional 1 percent loss in performance at sea level and in smaller increase in loss of performance at higher altitudes.

Report presenting an investigation of the effects of many of the parameters significant to wing flutter on several untwisted rotating models to determine their significance with respect to stall flutter of propeller blades. The parameters included torsional stiffness, section thickness ratio, sweepback, length-chord ratio, section center-of-gravity location, blade taper, Mach number, and fluid density. Results regarding the considerations on method of presentation, experimental data and discussion, some possible applications, and a comparison of experiment with classical-flutter theory are provided.

Fuels having Reid vapor pressures of 6.3 and 1.0 pounds per square inch were investigated in a tail-pipe burner on an axial-flow-type turbojet engine at a simulated flight Mach number of 0.6 and altitudes from 20,000 to 45,000 feet. With the burner configuration used in this investigation, having a mixing length of only 8 inches between the fuel manifold and the flame holder, the low-vapor-pressure fuel gave lower combustion efficiency at a given tail-pipe fuel-air ratio. Because the exhaust-nozzle area was fixed, the lower efficiency resulted in lower thrust and higher specific fuel consumption. The maximum altitude at which the burner would operate was practically unaffected by the change in fuel volatility.

Report discussing the results of an investigation to determine the stability and control characteristics of a flying model of an unswept-wing vertically rising airplane. Information about stabilization, maneuverability, rolling motions, and landings is provided.

Report presenting an investigation to determine the stability and control characteristics of a vertically rising airplane model. Results of preliminary hovering flight tests are made in still air, away from the interference effects of the ground and side walls, and with normal airplane-type controls operating in the slipstream.

Report presenting an investigation of water landings in the impact basin with a model with a flat rectangular planing surface, a pulled-up bow, and a simulated landing wheel. Runs were made at several wave conditions, trim ranges, flight-path angles, and beam loadings. The results were found to be applicable in predicting loads and motions exhibited by a flat rectangular ski during impact with a water surface.

The effects of water injection on a compressor are presented. To determine the effects of varying water-air ratio, the compressor was operated at a constant equivalent impeller speed over a range of water-air ratios and weight flows. Operation over a range of weight flows at one water-air ratio and two inlet air temperatures was carried out to obtain an indication of the effects of varying inlet air temperature. Beyond a water-air ratio of 0.03 there was no increase in maximum air-weight flow, a negligible rise in peak total-pressure ratio, and a decrease in peak adiabatic efficiency. An increase in inlet air temperature resulted in an increase in the magnitude of evaporation. An analysis of data indicated that the magnitude of evaporation within the compressor impeller was small.

Report presenting testing using a Douglas D-558-I airplane to determine the effect of wing vortex generators on some of the undesirable handling characteristics of aircraft flying at hypercritical speeds. The effects on buffeting, lateral unsteadiness, change in trim, and loss of control effectiveness were the primary objectives.

An investigation was made of the variation of the pressure limits of flame propagation with tube diameter for quiescent propane with tube diameter for quiescent propane-air mixtures. Pressure limits were measured in glass tubes of six different inside diameters, with a precise apparatus. Critical diameters for flame propagation were calculated and the effect of pressure was determined. The critical diameters depended on the pressure to the -0.97 power for stoichiometric mixtures. The pressure dependence decreased with decreasing propane concentration. Critical diameters were related to quenching distance, flame speeds, and minimum ignition energy.

Report presenting an investigation in the free-flight tunnel to determine the dynamic lateral stability and control characteristics of a high-aspect-ratio bomber model with self-supporting, free-floating fuel tanks attached to the wing tips. The results showed that the flight behavior of the configuration could be made satisfactory when sufficient restoring moment was supplied. Results regarding the flight behavior, rolling motions, motions of the bomber and attached tanks, and flight records for different gearing ratios are provided.

Report presenting an investigation in the free-flight tunnel to determine the dynamic lateral stability and control characteristics of a coupled airplane configuration with simplified fighter models attached to the wing tips of a simplified bomber model. The configuration is meant to represent fighter airplanes carried on the wing tips of a bomber airplane to provide fighter protection for the bomber or for in-flight fueling. Results regarding the fighters attached with freedom in roll, with freedom in roll and pitch, and with freedom in roll, pitch, and yaw are provided.

"A supplementary investigation has been conducted in the Langley 20-foot free-spinning tunnel of a 1/30 -scale model of the Grumman XF10F-1 airplane to determine what effect full-span slats would have on the spin-recovery characteristics of the swept-wing version of the XF10F-1 airplane, which had previously been indicated as possessing undesirable spin-recovery characteristics without slats. The effects of extended nose-wheel doors and of fairing the air-duct inlets were also determined" (p. 1).

Report presenting an experimental investigation utilizing rocket propelled vehicles in free flight to determine some effects of fuselage interference, wing interference, and sweepback on the damping-in-roll characteristics of untapered wings with an aspect ratio of 3.7 and NACA 65A009 airfoil sections between a range of Mach numbers.

Examination of published data for some 52 isotopes indicates that the neutron energy for which the first resonance occurs is related to the magnitude of the thermal absorption cross section. The empirical relation obtained is in qualitative agreement with the results of a simplified version of the resonance theory of the nucleus of Breit-Wigner.

The results of an experimental investigation of the load distribution over two triangular wings in sideslip at Mach numbers from 1.20 to 1.79 are presented and compared with theory. The two wings tested have identical plan form, 45 degrees sweepback of the leading edge, and an aspect ratio of 4.0. One model was composed of round-nose airfoil sections and the other of sharp-nose, biconvex sections. For both wings the maximum thickness of streamwise sections was 6 percent and was located at the 30-percent chord.

Report presenting the results of an experimental investigation of the pressure distribution over two triangular wings at supersonic speeds. The two wings which were tested had identical plan forms, 45 degrees of sweepback of the leading edge, and an aspect ratio of 4.0, but different airfoil sections. Results regarding the pressure distribution at zero lift, flow characteristics and pressure distribution at angles of attack, normal-force coefficients, and application of results to other triangular wings are provided.

Memorandum presenting the pressure recovery, mass flow, and axial force of four bodies with nose inlets measured at Mach numbers between 1.4 and 2.0 and angles of attack of 0, 3, 6, and 9 degrees. The drag coefficients of axially symmetric diffusers operating at the maximum mass-flow rates were calculated from schileren photographs of the head shock waves and frictional drag considerations. Results regarding open-nose diffusers and conical-shock diffusers are provided.