Report presenting an investigation of the low-speed longitudinal stability and control characteristics of a scale model of a Bell X-5 airplane design with various leading-edge slat and trailing-edge flap arrangements. A marked increase in stability with increasing sweep angle at low lift coefficients was noted. Results regarding the basic longitudinal characteristics, leading-edge slats, trailing-edge flaps, and longitudinal control are provided.

Report presenting a description and results of an investigation of a model of the XH-17 two-blade, jet-powered helicopter. Tests were made with a standard configuration and with several modifications, including varying the size of blade counterweights, changing the control stiffness and chordwise bending stiffness of the blades, and varying the pylon and undercarriage damping and spring constants. Results regarding flutter testing, ground-vibration tests, and three-per-revolution rotor-blade unsymmetric bending oscillations are provided.

Report presenting flight tests at Mach numbers from 0.8 to 1.4 on three rocket-propelled general research models of airplane configurations. Two models had thin unswept tapered wings of aspect ratio 3 and hexagonal airfoil sections, two wings had different structural stiffness characteristics, and the third model had no wing. Results regarding the static and dynamic longitudinal stability, control, trim, and drag characteristics are provided.

The outstanding oxidation resistance of molybdenum disilicide at 2400 F and above was found to depend on the formation of a protective siliceous coating which a-cristobalie has been identified. Molybdenum disilicide is not inherently resistant to oxidation and in powdered form burns at low temperatures.Melting and casting experiments have demonstrated the decomposition of the material at the melting point. The room-temperature modulus of elasticity has been determined and electric-resistivity data are given to 2000 F.

Report presenting time histories of the aerodynamic loads on the vertical and horizontal tail surfaces of a jet-powered bomber airplane (B-45A) in sideslip maneuvers. Information about maximum measured rudder and fin loads, maximum total vertical-tail load, horizontal-tail-load dissymmetry, maximum elevator loads, and elevator-load dissymmetry is provided.

The results obtained from measurements of gust velocities, draft velocities, and ambient-air temperature within thunderstorms for the period September 17, 1946 to September 18, 1946 at Orlando, Fla. are presented herein. These data are summarized in tables I, II, and III, respectively, and are of the type presented in reference 1 for previous flights.

"Tests were made with a 1/16 size dynamically similar model of the Navy XP2V-1 airplane to study its performance when ditched. The model was ditched in calm water at the Langley tank no. 2 monorail. Various landing attitudes, speeds, and conditions of damage were simulated" (p. 1).

"At the request of the Air Materiel Command an investigation was made in the Langley free-flight tunnel to determine the static longitudinal stability and control characteristics of models coupled together in a tandem configuration proposed by All American Airways, Inc. Force tests were made using 1/20-scale models of B-29 end F-80 airplanes to determine the effects of coupling the fighter to the tail of the bomber. The results of the investigation showed that for the bomber alone the aerodynamic center was 0.21 mean aerodynamic chord behind the center of gravity (stable) but that for the tandem configuration the aerodynamic center was 0.09 mean aerodynamic chord forward of the center of gravity, of the combination (unstable)" (p. 1).