A report to the Weather Bureau, Washington DC, from the chairman of the Subcommittee on the Atmosphere in Relation to Aeronautics describing the activities accomplished and the proposal of work to be undertaken by the subcommittee.

Report presenting the gross weight and uranium investment of nuclear-powered, direct-air, shieldless, ram-jet missiles for a range of altitudes and Mach numbers. Results regarding the effect of reactor operating conditions and flight conditions on ramjet performance and effect of assumptions on ramjet performance are provided.

Report discussing the mutual interference effects of tail surfaces and a stern propeller on a model of the XB-42.The main focus was to determine the effect of tail surface-propeller spacing upon the periodic tail surface loading coincident with propeller blade passage.

Report discussing the low-speed stability and control characteristics of a modified model of the MX-1554A with a triangular wing and triangular stabilizing surfaces, which are designed to give more satisfactory stability and control than previous versions. Other modifications included an increase in slotted-flap span, redesigned tip aileron, fuselage tail cone, and speed brakes. Results provided include the effect of flow-control devices, tank and pylon location, a ground board, rotary stability derivatives, and a single support strut on the stability, control, and aerodynamic characteristics.

From Summary: "The reactor operating conditions were varied to enable selection of values giving a good compromise between low uranium investment and loss gross weight at each altitude and flight Mach number considered. The corresponding values of reactor and missile operating conditions are presented in the report."

"A porous wall was used in an attempt to eliminate reflections of oblique waves from a tunnel wall. Calculations were made of the required resistance characteristics of a wall in order that the flow through the wall, due to the pressure difference across a shock wave, would equal the component normal to the wall of the flow behind the shock wave. The resistance characteristic of a sintered bronze wall was measured and the reflections of waves impinging on the wall were observed at a Mach number of 1.62" (p. 1).

Report discussing testing on a series of tapered swept wings under conditions simulating rolling flight. The lift, longitudinal-force, and pitching-moment characteristics for three swept wings are provided. The results indicated that a decrease in taper ratio on a swept wing caused a small decrease in damping in roll at low and moderate lift coefficients.

Contains results of tunnel tests to determine effects of various combinations of split flaps, slats, and nose slats on the stability characteristics of a tapered 37.5 degree sweptback wing of aspect ratio 3 in straight and rolling flow.

Report presenting an investigation in the stability tunnel to determine the effect of airfoil profile on symmetrical sections on the static- and yawing-stability derivatives of three untapered wings of 45 degrees sweepback. All of the wings had an aspect ratio of 2.61. Results regarding the characteristics in straight flow, yawing flow, and drag index are provided.

Report presenting an investigation of the low-speed, power-off static longitudinal stability and control characteristics of a canard model with a triangular wing and horizontal tail in the free-flight tunnel. Results regarding the horizontal tail used to overcome change in stability and horizontal tail used for longitudinal control are provided.

Report presenting turbulent-boundary-layer profiles at large Reynolds numbers and with Mach numbers up to 1.2. In this investigation, velocity profile shapes were substantially unaffected by compressibility. Results regarding the temperature considerations, velocity profiles, and turbulent boundary layer under normal shock are provided.

Report presenting an investigation of a 1/21-scale model of the Chance Vought F7U-3 airplane in the 20-foot free-spinning tunnel to determine the erect and inverted spin and recovery characteristics for combat loading in the clean condition. Results regarding erect spins, inverted spins, spin-recovery parachutes, and recommended recovery technique are provided.

Report presenting an investigation of the effects of several molding conditions on the physical properties of laminates prepared with Fiberglass 181 glass fabric and Bakelite XRS-81 unsaturated-polyester resin. The molding variables included pressure, temperature, and time during both precuring and curing operations. The laminates were tested for several physical properties including resin content, percentage of voids, specific gravity, and flexural strength on the diagonal, both wet and dry.

From Introduction: "The propulsive jet that discharges from the base of a missile body or nacelle may, by interaction with external stream, cause important drag and stability changes. This paper presents some results of recent investigations by the Lewis and Langley laboratories of the jet effect on body end pressures and drag at zero lift."

From Summary :"A series of charts are presented by which the wing torsional stiffness required to meet a given standard of rolling effectiveness may be quickly determined. The charts may also be used to obtain quickly the aileron reversal speed and the variation of the loss in rolling effectiveness with airspeed. The charts apply to linearly tapered wings and elliptical wings of tubular-shell construction having various aspect ratios with aileron span and location of ailerons as variables. In the derivation of the charts, induced lift effects have been taken into account and the form of the wing-torsional-stiffness curve has been assumed."

Report presenting information on the amount and relative intensity of atmospheric turbulence for altitudes up to 60,000 as obtained by airplanes and balloon-borne instruments. Analysis of the data obtained indicated that there are substantial reductions in turbulence at higher altitudes in the weather conditions measured in the tests. Results regarding gust distributions, including non-thunderstorm turbulence, thunderstorm turbulence, total gust distributions, and a comparison of gusts are also provided.

A method is developed consistent with the assumptions of small perturbation theory which provides a means of determining the downwash behind a wing in supersonic flow for a known load distribution. The analysis is based upon the use of supersonic doublets which are distributed over the plan form and wake of the wing in a manner determined from the wing loading. The equivalence in subsonic and supersonic flow of the downwash at infinity corresponding to a given load distribution is proved.

Report discussing the suitability of 42 aromatic amines as antiknock additives for aviation gasoline at low temperatures similar to the ones encountered in flight.

Report presenting wing loads and load distributions obtained by differential-pressure measurements between the upper and lower surfaces of the left wing of the Douglas X-3 to determine the effects of angle of attack and Mach number on the wing characteristics at transonic Mach numbers. The wing had an aspect ratio of 3.09 and a modified 4.5-percent-thick hexagonal section. Data covered a range of lift values and Mach numbers.

From Summary: "Results are presented of an analysis of the strain-gage measurements of vertical-tail loads experienced in rudder pulses, gradually increasing sideslips, and rudder-fixed aileron rolls at transonic speeds with the Douglas X-3 research airplane."

"An investigation has been undertaken on two dynamic models simulating 1/20-scale and 1/25-scale models of propeller-driven tail-sitter vertically rising airplanes to determine the altitude required to approach normal-flight conditions after power failure in hovering flight. The results of the investigation indicated that, for the two models investigated, an altitude of 3,600 to 5,400 feet may be required to attain normal gliding flight" (p. 1).

The three papers collected here are: 'The Effect of Nose Shape on the Drag of Bodies of Revolution at Zero Angle of Attack.', 'Base Pressure on Wings and Bodies with Turbulent Boundary Layers', and 'Flow over Inclined Bodies'. The subject of the first paper is the drag of the nose section of bodies of revolution at zero angle of attack. The main object of the second paper is to summarize the prinicpal results of the many wind tunnel and free flight measurements of base pressure on both bodies of revolution and blunt trailing edge airfoils.

From Summary: "An experimental investigation was made to determine the permeability and strength characteristics of a number of sintered, porous, hollow turbine rotor blades and to determine the effectiveness of the blade fabrication method on permeability control. The test blades were fabricated by the American Electro Metal Corporation under a contract with the Office of Naval Research, Department of the Navy, and were submitted to the NACA for testing. Of the 22 test blades submitted, ten were sintered but not coined, five were sintered and coined, and seven were sintered and not coined but contained perforated reinforcements integral with the blade shells. Representative samples of each group of blades were tested."

Review of certain characteristics necessary to determine skin friction and heat transfer on the surfaces of high-speed missiles, including temperature recovery, skin-friction coefficients and heat-transfer coefficients of laminar and turbulent boundary layers, and the position of the transition from laminar to turbulent flow. A comparison is also made between existing flight data and results computed by the boundary-layer momentum-integral method in an attempt to establish design criteria for missiles that are very different from the typical shape.