Report presenting an investigation conducted on the helicopter test tower to determine experimentally the low tip Mach number stall and high tip Mach number drag divergence characteristics of a helicopter rotor with an NACA 0009 tip airfoil section. Results regarding rotor hovering performance, rotor-blade pitching moments, rotor profile-drag torque, and a comparison with two-dimensional drag-divergence data are provided.

Report presenting testing in the high-speed 7- by 10-foot tunnel to investigate the high-subsonic static longitudinal stability characteristics and lift-drag ratios of several wing-body models designed to provide high lift-drag ratios at Mach number 1.4. The basic configuration had a thin highly swept wing of aspect ratio 2.91 with NACA 65-A series airfoil sections. Results regarding longitudinal stability, lift, drag, and lift-drag ratio are provided.

Report presenting an investigation to determine the effects of leading-edge radius and profile thickness on the oscillatory lateral stability derivatives for a series of delta wings with 60 degrees of leading-edge sweep. The wings were oscillated in yaw about their vertical axes. Results indicated that there were noticeable decreases in all the derivatives due to increase in leading-edge radius at angles of attack above approximately 12 degrees.

Report presenting a wind-tunnel investigation at low speeds to determine the flight characteristics of a model of a sweptback-wing jet-transport airplane equipped with an external-flow jet-augmented slotted flap. Results regarding the longitudinal stability characteristics, longitudinal control characteristics, lateral stability characteristics, and lateral control characteristics are provided.

Report presenting an investigation conducted in a turbojet engine mounted in a sea-level test stand to determine the vibrational characteristics of four representative types of air-cooled turbine blades.Two were standard-span blades and two were long-span blades for high mass-flow turbines. Results regarding the coolant-flow rate, vibratory stresses, vibrational characteristics, and failures are provided.

Report presenting a study in which the effective flow area of a convergent exhaust nozzle was reduced by injecting a high-pressure secondary jet into the nozzle near the exit. Analytical expressions relating the performance with significant design and operating variables were developed. Some of the configurations, altered to operate as jet deflectors, produced significant values of side force but also operated at reduced effective flow area.

Report presenting experimental results relating to the effect of pressure gradient on the location of transition for several constant-pressure-gradient models an two power-profile models. Results regarding the local flow conditions, recovery-factor distributions, effect of unit Reynolds number, and effect of pressure gradient are provided.

From Summary: "An analysis is given of the oscillatory motions of vehicles which traverse ascending and descending paths through the atmosphere at high speed. The specific case of a skip path is examined in detail, and this leads to a form of solution for the oscillatory motion which should recur over any trajectory. The distinguishing feature of this form is the appearance of the Bessel rather than the trigonometric function as the characteristic mode of oscillation."

Report presenting power spectral methods of analysis as applied to flight test measurements of the strain responses of a large swept-wing bomber airplane in rough air in order to determine the effects of airplane in rough air in order to determine the effects of airplane structural dynamics on the strain responses.

The charts presented give the compressive buckling coefficients for a single-truss-core and a double-truss-core sandwich plate. These charts cover a wide range of sandwich proportions and may be used for sandwiches with unequal faces. They apply to inplane compressive loads acting parallel or perpendicular to the core direction or for various combinations of these loads. (author).

Report presenting the emergence- and planing-spray characteristics of flat-bottom surfaces representing hydro-skis with various bow shapes and deflectors. The most favorable emergence spray was obtained with a bow of triangular plan form and sharp profile. Results regarding practical design considerations are also provided.

Note presenting compressive strength test results from room temperature to 1000 degrees Fahrneheit and compressive creep test results from 700 to 1000 degrees Fahrenheit for plates of 17-7 PH stainless steel, Condition TH 1050, which were edge-supported in V-groove fixtures. The combinations of average stress, temperature, and time that produce given amounts of creep strain or failure are shown on master curves which facilitate interpolation of the test results.

"Measurements of runway roughness obtained by a profile-survey method are presented. A variety of runway lengths or sections and degrees of roughness were measured. The results are presented as elevation profiles of the runways surveyed and in the form of power spectra" (p. 1).

Report presenting a low-speed investigation made in the stability tunnel to study the effect of spoiler location, spoiler size, and fuselage nose shape on the directional stability characteristics of a model of a tandem-rotor helicopter fuselage. The model was found to be directionally unstable at certain positive angles of attack.

Report presenting a wind-tunnel investigation at full scale to determine the effect of flap location on the jet-flow momentum coefficient required to control the flap boundary layer when blowing from the wind shroud on the YF-86D airplane. The data presented show the change in lift coefficient with changes in momentum coefficient for various flap deflections, flap positions, and nozzle heights.

Report presenting the measured static-pressure distributions at the model surfaces and in surrounding flow field for a variety of bodies of revolution with locations of maximum cross-sectional areas at 0.3, 0.4, 0.5, 0.6, and 0.7 of the body length. Data were obtained with various bodies of fineness ratio 12 at zero angle of attack.

Report presenting an investigation of the effects of fabrication-type surface roughness on turbulent skin-friction drag at supersonic speeds. It was found that fabrication of the thin-skin constructions could be done sufficiently well in practice so as to cause no increase in drag over the smooth body; however, the juncture-type roughnesses produced significant increases in drag as compared with the smooth body. Results indicated that increasing the unit Reynolds number has a detrimental effect and increased the Mach number has a powerful alleviating effect on drag due to surface roughness.

Report presenting a flight investigation to determine the acceptability of a small side-located controller which is used as the primary airplane controller in an irreversible hydraulic-power control system. Pilot opinion was obtained concerning the acceptability of the controller while performing lateral and longitudinal maneuvers in a jet-trainer airplane at cruising-flight conditions. Results indicated that the location of the controller is consistent with pilot comfort and the airplane is flyable with the side-located controller.

Report presenting studies of the influence of various heat treatments on the rupture properties and microstructure of an alloy to provide more fundamental information on the relationships between structure and high-temperature properties in alloys of this type. Results regarding the effect of solution-treating temperatures, effect of cooling rate after solution treatment, effect of isothermal aging after solution treatment, cellular precipitation, and effect of rupture testing on structures are provided.

From Summary: "Approximate equations are derived for the induced power required and blade loading of a lifting rotor operating in the power-on vertical-descent range. The approximate relations, which are based upon certain assumptions as to the nature of the flow pattern, yield, for the induced power variation, results which are in general agreement with the available experiment data."

"Theoretical buckling stresses are determined in explicit form for circular cylinders with circumferential and axial stiffening. The loadings are axial compression, radial pressure, hydrostatic pressure, and torsion. Analyses were confined to moderate-length and long cylinders" (p. 1).

Report presenting a wind-tunnel investigation of the effects of fixing boundary-layer transition with wires on the aerodynamic characteristics of a wing-body configuration at a range of Mach numbers. The model consisted of an aspect-ratio-3 trapezoidal wing with a 3-percent-thick biconvex section in combination with a Sears-Haack body of revolution. Results regarding lift characteristics, pitching-moment characteristics, and drag characteristics are provided.

Note presenting calculations made of the magnitude of the surface sound pressure levels that will occur on blunt-nosed vehicles during reentry into the earth's atmosphere. The results presented cover a wide range of re-entrance velocities and reentrance angles into the atmosphere and sizes and weights of the vehicle.

Note presenting a comprehensive review on the method of split rigidities. The principles on which the method is based are discussed and it is shown how these principles are applied. The method is applied to several examples of using this method to calculate buckling stresses of structures that buckle in composite modes.