Report presenting an investigation studying the effects of compressibility on the internal-flow characteristics of an NACA 1-series cowling-spinner combination equipped with a dual-rotation propeller at Mach numbers up to 0.8. Two propellers were examined, one with a sealed propeller-spinner juncture and one with a raised-platform-airfoil shaped juncture. The propeller was not found to have appreciable compressibility effects on the impact pressures when operating at design cruise blade angle.

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 discussing tests on a helicopter rotor powered by ram-jet engines located at the rotor blade tips. Information about the basic hovering characteristics of the rotor and the propulsive characteristics of the ram-jet engine were obtained over a range of speeds and fuel rates. Results were also obtained in the power-off condition and with the engines removed.

"Aeroelastic instability phenomena of isolated open and closed rigid bodies of revolution free to move under elastic restraint have been investigated experimentally at low speeds by means of models suspended at zero angles of attack and yaw on slender flexible struts from a wind tunnel ceiling. Three types of instability were observed - flutter similar to classical bending-torsion flutter, divergence, and an uncoupled oscillatory instability which consists in nonviolent continuous or intermittent small-amplitude oscillations involving only angular deformations. The speeds at which this oscillatory instability starts were found to be as low as about one-third of the speed at flutter or divergence and to depend on the shape of the body, particularly that of the afterbody, and on the relative location of the elastic axis" (p. 1).

Report presenting an experimental investigation using a 1 7/8-inch diameter burner to determine the suitability of residual fuel oils as carriers in magnesium slurries. Four residual fuel oils with varying viscosities were investigated by themselves and in slurries of 50 percent magnesium. Results regarding the settling characteristics, blow-out velocity, and combustion efficiency are provided.

Report presenting testing of the transonic longitudinal characteristics of a model of the McDonnell XF3H-1 airplane. The model had a center-of-gravity location of 28.5 percent of the mean aerodynamic chord and a stabilizer setting of -5.91 degrees relative to the wing chord plane with extensible rocket racks. Results regarding Reynolds number, rocket-rack program, flight time history, trim, lift, drag, longitudinal stability, directional stability, and inlet pressure recovery are provided.

Memorandum presenting the results of a test on the transonic longitudinal characteristics of a scale rocket model of the McDonnell XF3H-1 airplane. The model, flown with a center-of-gravity location of 28.5 percent of the mean aerodynamic chord and a stabilizer setting of -5.91 degrees relative to the wing chord plane, was equipped with extensible rocket racks. Results regarding the Reynolds number, rocket-rack program, flight time history, trim, lift, drag, longitudinal stability, directional stability, and inlet pressure recovery 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.

From Introduction: "This paper will treat the problem in the suggested manner, beginning with the development of a suitable boundary condition to represent mathematically a homogeneous boundary which has the same flow characteristics, at a point in the flow sufficiently removed from the boundary as the actual physical boundary of alternate open and closed portions of the wall. Numerical results will be presented for circular tunnels with uniformly distributed around the circumference, for rectangular tunnels with uniformly distributed around the circumference, for rectangular tunnels with uniformly distributed slots in the top and bottom walls, for rectangular tunnels with the slot distribution determined by a transformation from a uniformly slotted circular tunnel, and for a two-dimensional tunnel. The results of this paper are derived on the basis of an incompressible potential flow."

Report discussing the importance of designing aircraft turbines so that the entire range of operating conditions has been considered. In this particular investigation, the compressor performance was used to determine the turbine design requirements for a turbine-propeller engine to be operated up to altitudes of 40,000 feet and flight velocities up to 600 miles per hour. The two modes of engine operation considered were constant exhaust-nozzle area and variable exhaust-nozzle area.

"During the flight investigation of the X-1 airplane the hinge moments of the elevator and aileron control surfaces have been measured over a Mach number range extending to above 1.0. The results of these measurements are presented in this paper" (p. 2).

Report presenting a free-fall investigation of airplanes in the transonic range using a configuration with 45 degree sweptback wing and tail surfaces. The lift, drag, and longitudinal static and dynamic stability and control characteristics were obtained at a range of operating lift coefficients and Mach numbers.

From Summary: "A limited investigation of a 1/24-scale dynamically similar model of the Navy Bureau of Aeronautics DR-77 design was conducted in Langley tank no. 2 to determine the calm-water take-off and the rough-water landing characteristics of the design with particular regard to the take-off resistance and the landing accelerations. During the take-off tests, resistance, trim, and rise were measured and photographs were taken to study spray. During the landing tests, motion-picture records and normal-acceleration records were obtained."

Report presenting an investigation to determine the effects of a horizontal tail on the longitudinal stability characteristics of a swept-back, twisted, and cambered wing in combination with a fuselage and various combinations of high-lift and stall-control devices. The ideal placement of the horizontal tail appeared to be at 6 percent wing semispan below the wing-root-chord plane.

Memorandum presenting tests made on a normal-shock inlet mounted as a scoop on a flat plate on which a turbulent boundary layer was generated. A boundary-layer-removal scoop was provided between the inlet and the plate and various amounts of the boundary layer were removed. Results regarding the main inlet, boundary-layer scoop, and an evaluation of results are provided.

Report presenting flight testing with two jet-propelled airplanes in rough air to investigate effects of sweep on gust loads and gust selectivity. Data was taken with an unswept-wing airplane and a 35 degree swept-wing airplane for incremental accelerations corresponding to airspeeds of 300 and 450 miles per hour. The results indicated that the swept-wing airplane experienced lower loads in turbulent air than the unswept-wing airplane.

From Summary: "A summary has been made of the available experimental data on division of normal-force loads between the wing and fuselage of aircraft. Comparison of the experimental values with theoretical calculations which include interference effects shows good agreement in general with the greatest differences occurring near a Mach number of 1.0. At high angles of attack, above the range of linear lift curves, the proportion of the total wing-fuselage load carried by the wing decreases and this effect occurs throughout the subsonic- and transonic-speed region."

Report presenting an investigation of systematic series of sharp- and blunt-trailing-edge wings to determine the effects of thickening the trailing edges on the lift, drag, and pitching moment characteristics at several Mach numbers. Results indicate that no appreciable zero-lift drag reduction can be obtained by thickening the trailing edges from 1.41 to 1.96, but trailing edges can be thickened appreciably with no increases in zero-lift drag.

Memorandum summarizing the lift and drag characteristics of a series of five low-aspect-ratio triangular-wing or modified triangular-wing airplane models. The series consists of three triangular wings of aspect ratios 2, 3, and 4 and two modified triangular wings of aspect ratio 2 with taper ratios of 0.20 and 0.33. The experimental lift and drag characteristics of the five models are compared with existing theory.

"Several methods of cyclic de-icing of a gas-heated airfoil were investigated to determine ice-removal characteristics and heating requirements. The cyclic de-icing system with a spanwise ice-free parting strip in the stagnation region and a constant-temperature gas-supply duct gave the quickest and most reliable ice removal. Heating requirements for the several methods of cyclic de-icing are compared, and the savings over continuous ice prevention are shown. Data are presented to show the relation of surface temperature, rate of surface heating, and heating time to the removal of ice" (p. 1).

Report presenting flight testing on models of the proposed Consolidated Vultee Aircraft Corporation MX-1626 airplane with nacelles and without nacelles. Results regarding drag level, design modifications, dampening, trimming, and the use of ventral boosters are provided.

The effects of inlet circumferential position around the fuselage on the characteristics of a half-conical scoop inlet having a 24.6deg half-angle cone have been investigated in the langley 4- by 4-foot supersonic pressure tunnel. Pressure-recovery results have been obtained at a Mach number of 2.01 for a fixed boundary-layer-bleed height which was 60 percent of the boundary-layer thickness at an angle of attack of 0deg, and for cowling position parameters of 42.4deg and 38.0deg. inlet had a capture area equal to 24.9 percent of the basic-fuselage frontal area. The angle of attack was varied from 0deg to 12deg.

Investigation of the effect on zero-lift drag of varying the size and number of symmetrically mounted nacelles on a 45 degree sweptback wing and body combination as determined by free-flight tests of rocket-propelled models over a range of Mach and Reynolds numbers. The nacelle configuration consisted of a twin-engine nacelle near the fuselage, a combination of single-engine nacelles at the wing tip and fuselage, a large nacelle at the wing tip, and a large nacelle near the fuselage.

Report presenting an analysis of some longitudinal maneuvers obtained during performance tests of the Convair XF-92A by using measured period and time to damp to half amplitude and with a computer to give a preliminary measurement of the airplane stability and damping at a range of Mach numbers. Results indicated that no loss in control effectiveness was shown, the static stability increased with Mach number, the damping was light but positive, and the damping factor was low.