Describes the characteristics of the citrus rust mite, the damage it causes to citrus fruits, and methods of control.

Note presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil with a porous surface to determine the reduction in section total-drag coefficient that might be obtained at large Reynolds numbers by the use of area suction. This report primarily deals with additional tests of the same airfoil model equipped with a porous skin of lower porosity.

Report presenting an investigation of hot-pressed molbdenum disilicide bodies produced by industrial processes at a temperature of 2950 degrees and a pressure of 3000 pounds per square inch. Results regarding the short-time tensile strength, stress-rupture data, compression strength, air-corrosion resistance, hardness, coefficient of linear thermal expansion, thermal conductivity, and density are provided.

"An investigation has been made of a partial-span model of the tail surface designed for use on the Hughes Falcon (MX-904) missile to determine the aerodynamic characteristics of the tail and elevator including elevator hinge moment. Data obtained at Mach numbers of 1.62 and 1.96 in the Langley 9- by 12-inch supersonic blowdown tunnel are presented for the condition where the tail was attached to a segment of the foreshortened body" (p. 1).

"Free-flight tests have been made to determine the drag at zero lift of several configurations of a missile having triangular wings and tails. Base-pressure measurements were also obtained for some of the configurations. The results show that increasing the wing thickness ratio from 4 to 6 percent increased the wing drag by about 100 percent at M = 1.3 and by about 30 percent at M = 1.8" (p. 1).

Report presenting a method for calculating the lift distribution due to twist which gives a closer approximation than the current Schrenk empirical method and requires about the same amount of computing. The method uses the lifting-line theory and makes use of the lift distribution due to angle of attack and considers the aspect ratio of the wing. Examples are presented for four main types of twist: symmetrical, antisymmetrical, continuous, and discontinuous.

Report presenting generalized expressions obtained by means of the linearized theory for the surface velocity potentials and the surface-pressure distributions due to lift and roll, the lift-curve slope, and the damping-in-roll derivative for a series of thin wings. The results of the investigation are presented in the form of generalized design curves for rapid estimation of the derivatives.

Report presenting an investigation to obtain basic performance and control characteristics of an aerodynamic-servocontrolled rotor system. Results regarding the hovering performance, low-speed flight performance, control effectiveness, transient response to collective pitch, and transient response to cyclic pitch are provided.

Note presenting an analysis of the performance and load-range characteristics of the turbojet engine for various flight speeds, altitudes, compressor pressure ratios, and turbine-inlet temperatures. The values of the lift-drag and structure-to-gross-weight ratios of the aircraft and the efficiencies of the engine components assumed for this analysis are representative of the best values obtained either in practice or in laboratory investigations. Results regarding engine performance, load-range characteristics, and effect of changes in engine weight and airplane characteristics are provided.

Note presenting an investigation to compare the dynamic lateral control characteristics provided by step plug ailerons with those provided by conventional flap ailerons on a sweptback-wing model. The model used had a 38 degree sweptback wing with an aspect ratio of 3 and a taper ratio of 0.5.

Report presenting the relation of spark-over voltage to gas density as a basis for a possible gas-temperature-sensing method. The investigation indicated that application of the spark-discharge mechanism to a gas-temperature-sensing method is feasible. Results regarding the types of electrode and effect of humidity, effect of cathode material, surface roughness, effect of gas velocity, effect of radiant energy, gas composition, effect of thermal expansion, miscellaneous effects, and reproducibility of spark-over voltage are provided.

Note presenting results of tests on duplicate longitudinal and transverse specimens of Alclad aluminum alloy 24S-T86 sheets with three nominal thicknesses. The stress-strain and stress-deviation graphs are plotted on a dimensionless basis to make them applicable to sheets of the alloy with yield strengths which differ from those of the test specimens.

From Summary: "The methods used in the application of the wire-mesh plotting device to find the flow pattern about a cascade of airfoils in compressible inviscid flow and some mathematical checks that increase the accuracy of this application are described. Results for two typical turbine-blade cascades are shown to compare well with experimental data. A method of utilizing the wire mesh to design turbine blades with a prescribed pressure distribution in incompressible flow is presented."

Report presenting the results of a wind-tunnel investigation to determine the effect of varying the amount and type of camber on the section characteristics of 10-percent-chord-thick NACA 64A-series profiles. Results regarding lift- and drag-divergence characteristics, lift characteristics, drag characteristics, and pitching-moment characteristics are provided.

Report presenting an investigation to obtain an improvement in the high-temperature properties and resistance to creep of magnesium-cerium forging alloys. Preliminary testing was carried out to determine the most optimum alloy and then further testing was carried out on different heats of magnesium containing various amounts of cerium.

Note presenting an investigation with airplane models in the free-flight and 20-foot free-spinning tunnels to determine whether a stable parachute could be safely towed behind an airplane in flight and whether it would be effective as a spin-recovery device. Results regarding the parachute characteristics, behavior in gliding flight, spin-recovery effectiveness, and effect of increasing towline length are provided.

Note presenting a review of literature relating to fire-extinguishing agents in order to ascertain the extent of present knowledge and to determine what research might lead to the development of more efficient agents for extinguishing fires in aircraft. An analysis of the extinguishing data was made in order to determine the relative extinguishing effectiveness of different substances and the basic mechanisms involved in the action of extinguishing agents.

Report presenting a compilation of flight test data on pitching angular accelerations. An analysis of the data was also made to establish methods for determining maximum pitching accelerations.

Report presenting a study of the correlation between molecular structure and physical properties of high-density hydrocarbons, including the net heat of combustion, melting point, boiling point, density, and kinematic viscosity. They are evaluated for their use as a fuel, especially in planes that are required to have smaller fuel tanks.

Report presenting the available sources of data on the mechanical properties of aluminum alloys at low temperatures and a summary of the material to be found in each source. General conclusions regarding commercially available aluminum alloys are also provided.

Report presenting the results of analytical studies of tail-pipe-burning, water-injection, and bleedoff methods of thrust augmentation that provide an insight into the operating characteristics and summarize the performance that may be obtained when applied to a typical turbojet engine. Results regarding bleedoff and water-injection rates, performance of the primary engine, and performance of the secondary engine, performance of the complete engine are provided.

This note is part of a program with the objective of finding practical ways of reducing the external noise level of light airplanes in order to make them less objectionable to people on the ground. The current report covers noise measurements on standard light airplanes and on similar airplanes equipped with engine mufflers, propeller reduction gears, and propellers with various numbers of blades and blade shapes. The results indicate that reductions in noise level were found to result from muffling the engine and from reducing propeller tip speed and blade loading.

Report presenting heat-transfer measurements on an air-cooled 20 degree cone with a laminar boundary layer at Mach number 2.02. The surface temperature in the instrumented area on the cone was essentially constant at all test conditions, but the area was preceded by severe surface-temperature gradients.

Report presenting a determination of the dynamic characteristics of a typical turbojet engine with a centrifugal compressor, a sonic-flow turbine-nozzle diaphragm, and a fixed-area exhaust nozzle. Results indicate that a linear differential equation for engine acceleration as a function of fuel flow and engine speed for operation near a steady-state operating condition can be written.