Report presenting an investigation in the 20-foot free-spinning tunnel to determine the erect and inverted spin and recovery characteristics of a 1/28-scale dynamic model of the North American FJ-4 airplane. Results indicated that either a flat-type or a steep-type spin maybe obtained when the airplane is spinning erect. Results regarding inverted spins, loading condition, spin-recovery rocket tests, and spin-recovery parachute tests are provided.

From Summary: "Incipient spin characteristics have been investigated on a 1/35-scale dynamic model of the Convair F-102A airplane. The model was launched by a catapult apparatus into free flight with various control settings, and the motions obtained were photographed. The model was ballasted for the combat loading. All tests were made with the speed brakes and landing gear retracted, and engine effects were not simulated."

From Summary: "An investigation was conducted in the 8-by-6 foot supersonic wind tunnel on the effect of exhaust-gas temperatures on the external and internal characteristics of a convergent-divergent nozzle having an area expansion ratio of 1.83. Data were obtained over a pressure-ratio range from 1 to 20 at free-stream Mach numbers of 1.6 and 2.0 for exhaust temperatures of 860 degrees, 1650 degrees, and 2000 degrees R. Results of this investigation indicated that generally both the internal and external performance characteristics were only slightly affected by a large change in jet temperature. The small differences in performance which did occur were predicted satisfactorily from theoretical considerations."

Control requirements were determined from calculated engine performance maps for a fixed-geometry ram jet of a configuration suitable for strategic supersonic missile propulsion. Several control schemes for attaining desired engine performance and for stabilizing missile flight velocity during cruise are presented. The advantages and disadvantages of each system are discussed.

Report presenting experimental data from calm- and rough-water landing impacts with a dynamic model of a seaplane incorporating a flat-bottom hydro-ski mounted on a rigid strut and on a shock-absorber strut. Results regarding the fixed-ski case and translating-ski case are provided.

Report presenting the zero-lift drag of a sweptback wing and body combination with nacelles with NACA 1-50-250 nose inlets locate in the wing tips as determined by flight tests of rocket-powered models at transonic speeds. Results regarding the pressure recovery and the effect of the nacelles on it are also provided.

Report presenting an investigation in the transonic blowdown tunnel at a range of Mach numbers to determine the increments in lift, drag, and pitching moments due to the installation of a semielliptical-shaped air inlet in the root of a 45 degree sweptback wing and to study the internal flow characteristics of the inlet. Results regarding the internal pressure measurements, effect of inlet installation on external aerodynamic characteristics, effect of boundary-layer removal on internal pressure recovery, and inlet performance are provided.

Memorandum presenting an investigation of the theoretical performance of a two-stage ballistic rocket missile with a centerbody and two parallel boosters for JP4-oxygen and ammonia-fluorine propellants. The missile using the ammonia-fluorine propellant weighs about one-half as much as a missile using JP4-oxygen. Results regarding the optimum missile and effect of variation of design parameters are provided.

From Introduction: "The present report deals with another phase of the investigation; that is, the effects on airfoil section characteristics of protuberances extending along the entire span from the airfoil surface."

Report presenting free-flight measurements of the zero-lift drag of a cruciform-finned body at a range of Mach and Reynolds numbers. Results regarding experimental total drag, comparison of theory with experiment, comparison of experiment with NOL results, boundary-layer transition, Reynolds number effects, and fin leading-edge shape are provided.

From Introduction: "Data are presented to show the effects of tail-pipe fuel-air ratio, altitude, and flight Mach number on tail-pipe-burner performance at rated engine speed and approximately constant turbine-outlet temperature. Operational characteristics of the tail-pipe burner and variable-area exhaust nozzle are also reported."

Report presenting a wind-tunnel investigation at low speed to determine the effects of sideslip on the static longitudinal trim characteristics of three fighter-type airplane models. The three models consisted of a 45 degree swept-wing model with a horizontal tail geometrically similar to the wing and mounted slightly below the wing, a clipped-delta-wing model with a horizontal tail mounted in a moderately high position, and a 60 degree delta-wing with no horizontal tail. Results regarding static longitudinal stability, variation of pitching-moment coefficient with sideslip, effect of modifications to Model B on static longitudinal stability and variation of pitching-moment coefficient with sideslip, and static lateral stability are presented.

"A metallographic microscope was developed with provision for heating a specimen to 1800 F in protective atmospheres, that is, vacuum or gas. A special objective was constructed of reflecting elements with an unusually long working distance (7/16 in.) and a high numerical aperture (0.5). Changes in specimen microstructure were observed and recorded on 35-millimeter motion-picture film. The resulting pictures were projected as motion pictures and individual frames were cut and enlargements made for close observation" (p. 1).

"Low-aspect-ratio wings having pointed plan forms are treated on the assumption that the flow potentials in planes at right angles to the long axis of the airfoils are similar to the corresponding two-dimensional potentials. For the limiting case of small angles of attack and low aspect ratios the theory brings out the following significant properties: (1) The lift of a slender, pointed airfoil moving in the direction of its long axis depends on the increase in width of the sections in a downstream direction. Sections behind the section of maximum width develop no lift. (2) The spanwise loading of such an airfoil is independent of the plan form and approaches the distribution giving a minimum induced drag. (3) The lift distribution of a pointed airfoil travelling point-foremost is relatively unaffected by the compressibility of the air below or above the speed of sound. A best of a triangular airfoil at a Mach number of 1.75 verified the theoretical values of lift and center of pressure" (p. 1).

Low-aspect-ratio wings having pointed plan forms are treated on the assumption that the flow potentials in planes at right angles to the long axis of the airfoils are similar to the corresponding two-dimensional potentials.

"A theoretical study was made of the shimmy of castering wheels. The theory is based on the discovery of a phenomenon called kinematic shimmy. Experimental checks, use being made of a model having low-pressure tires, are reported and the applicability of the results to full scale is discussed. Theoretical methods of estimating the spindle viscous damping and the spindle solid friction necessary to avoid shimmy are given. A new method of avoiding shimmy -- lateral freedom -- is introduced" (p. 147).

"The method of Poggi is used to calculate, for perfect fluids, the effect of compressibility upon the flow on the surface of an elliptic cylinder at zero angle of attack and with no circulation. The result is expressed in a closed form and represents a rigorous determination of the velocity of the fluid at the surface of the obstacle insofar as the second approximation is concerned. Comparison is made with Hooker's treatment of the same problem according to the method of Janzen and Rayleight and it is found that, for thick elliptic cylinders, the two methods agree very well" (p. 245).

From Summary: "Stability and control characteristics determined from tests in the Langley 19-foot pressure tunnel of a 0.2375-scale model of the Douglas XA-26 airplane are compared with those measured in flight tests of a Douglas A-26 airplane. Agreement regarding static longitudinal stability as indicated by the elevator-fixed neutral points and by the variation of elevator deflection in both straight and turning flight was found to be good except at speeds approaching the stall. At these low speeds the airplane possessed noticeably improved stability, which was attributed to pronounced stalling at the root of the production wing."

Report presenting a wind-tunnel investigation to determine the effects of two wing-root leading-edge plan-form modifications, including a notched leading-edge fillet and a rounded leading-edge fillet, on the low-speed longitudinal stability characteristics of an airplane model with a 50.7 degree sweptback wing. Results regarding stability at zero lift, variation of stability with lift coefficient, and lift and drag characteristics are provided.

Report presenting performance testing of a supersonic compressor designed for a tip speed of 1400 feet per second, a pressure ratio of 2.0, and a corrected weight flow of 30.5 pounds per second. The overall performance results of the rotor alone at design speed gave a pressure ratio of 2.17, an adiabatic efficiency of 89 percent, and a weight flow of 28 pounds per second. A comparison with the predicted design results is provided.

The J33-A-27 compressor was operated at an inlet pressure of 14 inches of mercury absolute and ambient inlet temperature over a range of equivalent impeller speeds from 6100 to 11,800 rpm. At the design equivalent speed of 11,800 rpm, the J33-A-27 compressor had a peak pressure ratio of 4.40 at an equivalent weight flow of 105.7 pounds per second and a peak adiabatic temperature-rise efficiency of 0.745. The maximum equivalent weight flow at design speed was 113.5 pounds per second.

An analog investigation of the power plant for a gas-turbine powered helicopter indicates that currently proposed turbine-propeller engine controls are satisfactory for helicopter application. Power increases from one-half to full rated at altitudes from sea level to 15,000 feet could be made in less than 4 seconds with either the rotor or propellers absorbing the engine power.

Report presenting an investigation to determine the effect on performance of two methods of throat-area modulation of two convergent plug nozzles. Data were obtained over a range of pressure ratios. Results regarding the performance of the translatable outer-shell-type plug nozzle, performance of the iris-outer-shell-type plug nozzles, sensitivity to throat-area variation, and air-flow parameter are provided.

"In this report are presented empirical working charts from which the distribution of lift between wings, that is the fraction of the total lift borne by each, can be determined in the positive lift range for any ordinary biplane cellule whose individual wings have the same profile. The variables taken directly into account include airfoil section, stagger, gap/chord ratio, decalage, chord ratio, and overhang. It is shown that the influence of unequal sweepback and unequal dihedral in upper and lower wings may be properly provided for by utilizing the concepts of average stagger and average gap/chord ratio, respectively" (p. 93).