Memorandum presenting an investigation to determine the roll effectiveness of a differentially deflected horizontal tail of a 42 degree swept-wing model. The model was tested through an angle-of-attack range of 0 degrees through the stall in the clean and landing configurations with the horizontal tail in a low position. Results regarding the longitudinal characteristics and lateral characteristics are provided.

An investigation was made in the Langley stability tunnel to study the influence of number of fins, fin shrouding, and fin aspect ratio on the spin instability of mortar-shell tail surfaces. It was found that the 12-fin tails tested spun less rapidly throughout the angle-of-yaw range than did the 6-fin tails and that fin shrouding reduced the spin encountered by a large amount.

Report discussing testing of a cruciform missile with a low-aspect-ratio wing and flap-type controls to determine the stability and control characteristics while rolling. Longitudinal stability and control effectiveness for this particular configuration were examined. The data obtained was compared to results from a similar model that was rolling significantly less.

Report presenting a brief summary of current loads information at hypersonic speeds and some ways of estimating the loads on aircraft components when designing an aircraft.

From Introduction: "The purpose of this report is to compare the effect on engine performance of the variable-area exhaust nozzle for axial- and centrifugal-flow turbojet engines."

Memorandum presenting a study of the effect of prestrain in tension upon the stress-strain characteristics in compression for copper and brass. The residual stress phenomenon known as the Bauschinger effect is of primary importance in cyclic loading, inasmuch as it serves to reduce the yield strength of plastically strained metal to deformation of the opposite sign.

Memorandum listing NACA reports related to a variety of research topics, including instruments, research equipment, and research techniques.

Report presenting an investigation of whether or not a two-stage turbine with the frontal area no larger than the compressor frontal area could be satisfactorily designed to drive a particular compressor under take-off conditions. The low blade-tip speed, high work, and high air flow per unit of frontal area of the compressor make it critical that a two-stage turbine is designed to drive it. Results regarding the effect of work division, effect of variation in cone angle, and effects of radial variations on velocity diagrams are provided.

From Summary: "Pressure distributions around circular cylinders placed perpendicular to the stream for subsonic and supersonic flow conditions have been obtained. Drag coefficients calculated from these wind-tunnel tests and from transonic free-flight tests are presented. Drag data are presented for the Mach number range of 0.3 to 2.9."

"Tabulated pressure coefficients and aerodynamic characteristics are presented for six spanwise stations on the left wing of the Bell X-1 research airplane. The data were obtained in an unaccelerated stall and in pull-ups at Mach numbers of 0.74, 0.75, 0.94, and 0.97" (p. 1).

Report presenting an investigation in the 19-foot pressure tunnel to determine the effects of a fuselage and a horizontal tail located at various vertical positions on the low-speed longitudinal characteristics of a circular-arc 52 degree sweptback wing. Results regarding the effect of fuselage on longitudinal characteristics of the wing, effect of tail position on stability and tail effectiveness, and air-flow characteristics are provided.

Report presenting a method for calculating the aerodynamic forces on the blades of a dual-rotating propeller with its thrust axis inclined to the air stream. Comparison of the fluctuating aerodynamic forces due to pitched or yawed operation of a dual-rotating propeller show that the fluctuation in forces on the front component tend to be greater than those on the rear component.

Report presenting studies of some of the effects of parameters such as Mach number, blade angle, and structural damping on the flutter of model helicopter rotor blades in the hovering condition. Forward movement of the blade chordwise center-of-gravity location tended to raise the flutter speeds at low pitch angles, but had no effect at high pitch angles. The significant flutter data for the tests along with detailed descriptions of the models are included to facilitate more detailed analyses.

Report presenting flight testing of a model of a cruciform missile configuration with a low-aspect-ratio wing equipped with flap-type controls in order to determine the stability and control characteristics while rolling at about 5 radians per second. Results indicated that if the ratio of roll rate to natural circular frequency in pitch is not greater than about 0.3, the motion following a step disturbance in pitch essentially remains in a plane in space. Results regarding time histories, normal force due to angle of attack, pitching moment due to angle of attack, damping, and control effectiveness are provided.

From Introduction: "This report is concerned with the derivation of expressions for the velocity potential and associated forces and moments for oscillating triangular wings in supersonic flow. The purpose of the present report is to make use of the expanded form of the velocity potential to obtain the forces and moments, based on the first terms of this potential, for a rigid triangular wing performing vertical and pitching sinusoidal oscillations in mixed supersonic flow."

Report presenting data from which the effects of transpiration air flow on average skin-friction coefficients and pressure drag of a conical model were evaluated. The model consisted of a truncated porous nose cone with a solid ogival nose section. Results regarding the pressure distribution, base pressure drag, average skin-friction coefficients, effects of transpiration air, and comparison with theory.

Report presenting an investigation in the 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.41, 1.61, and 2.01 of a model of a 45 degree swept-wing fighter airplane. Results regarding the static stability characteristics and lateral and directional control are provided.

Report presenting a simplified analog simulator that can be used to predict the minimum comfortable approach speeds that could be used in carrier landings for airplanes that are limited by their ability to control altitude. Predicted speeds from initial tests on several planes are compared with values from flight tests in order to indicate the validity of simulator results.

"A ditching investigation was made of a l/l2-scale dynamically similar model of the Douglas F4D-1 airplane to study its behavior when ditched. The model was landed in calm water at the Langley tank no. 2 monorail. Various landing attitudes, speeds, and configurations were investigated. The behavior of the model was determined from visual observations, acceleration records, and motion-picture records of the ditchings. Data are presented in tables, sequence photographs, time-history acceleration curves, and attitude curves" (p. 1).

Report presenting force testing on an NACA 3-(3)(05)-05 eight-blade dual-rotating propeller at a range of blade angles. Results indicated that good efficiencies can be obtained at high subsonic forward Mach numbers by operation at high blade angle. Results regarding the propeller characteristics, individual power coefficients, effect of forward Mach number on the maximum efficiency of the dual propeller, and effect of small changes in the rear-propeller blade angle on the dual-propeller characteristics are also provided.

From Summary: "The NACA model 40 series of flying-boat hull models consists of 2 forebodies and 3 afterbodies combined to provide several forms suitable for use in small marine aircraft. One forebody is the usual form with hollow bow sections and the other has a bottom surface that is completely developable from bow to step. The afterbodies include a short pointed afterbody with an extension for the tail surfaces, a long afterbody similar to that of a seaplane float but long enough to carry the tail surfaces, and a third obtained by fitting a second step in the latter afterbody."