Describes methods for successfully growing alfalfa, including insect and disease control.

Describes the life cycles and characteristics of insects that threaten peach trees in the eastern United States.

From Summary: "A flight investigation has been made of the practical problems associated with the use of porous-leading-edge suction. The wing leading edge of the test airplane was porous over approximately 83 percent of the span and the first 8 percent of the chord on the upper surface. Various other extents of suction area within these limits were also tested."

Report presenting an investigation of a 1/19-scale model of an unswept-wing trainer airplane in the 20-foot free-spinning tunnel to determine the rocket spin-recovery characteristics of the model for comparison with available full-scale-airplane results. A rocket was attached to each wing tip to fire in a direction to apply an antispin yawing moment about the Z body axis. Results regarding the full-scale spin recoveries by rockets, model spin recoveries by rudder reversal, model spin recoveries by rockets, and mass changes associated with installation of emergency device are provided.

Note presenting an investigation of some of the possible mathematical troubles that may occur in the iterative procedure so much in use in present-day aerodynamics. The analysis indicates the general undesirability of determining the velocity potential or the stream function in the form of a series whose coefficients are analytically developed in a power series of some parameter.

Report presenting a soap-bubble, constant-pressure method to measure laminar burning velocities of some hydrocarbon-nitrogen-oxygen mixtures. Results regarding the evaluation of the soap-bubble method of measurement and burning velocities of hydrocarbon-oxygen-nitrogen mixture are provided.

Note presenting an analysis of the propulsive thrust and specific impulse attainable by cooling aircraft surfaces with liquefied or solidified gases with vaporization temperatures lower than the equilibrium surface temperature. Use of coolant vaporization as the sole means of propulsion yields low specific impulses at low speeds.

Report presenting a study of the flow distribution throughout the passage of a rotating impeller, and the results are presented in the form of relative velocity and relative pressure loss contours. The loss and velocity distributions indicate that secondary flows in the boundary layer tend to shift the low-energy air toward the blade suction within the passage. Results regarding the overall performance, performance within the passage, secondary flow and clearance effects, and a comparison with the hot-wire anemometer surveys are provided.

Note presenting the effect of inclination of the airstream on the static pressure measured by two essentially similar service pitot-static tubes and by one of those tubes with three modified orifice arrangements as determined in flight. Results regarding initial calibrations at Mach numbers from 0.20 to 0.24 and the final orifice configuration are provided.

"The analogy between a ball rolling over a contoured surface and a pitching and yawing aircraft is developed. Test results from a model representing a missile with linear moment characteristics are presented to verify the analogy. Several examples of the behavior of nonlinear systems are also given" (p. 1).

Report presenting some information relative to the prediction of shock-induced boundary-layer separation. Experimental results showing the effects of Reynolds number and Mach number on the separation of both laminar and turbulent boundary layers are given and compared with results obtained by available methods for predicting separation.

Report presenting an investigation of laminar, transitional, and turbulent boundary layers in a subsonic wind tunnel at two Mach numbers at various Reynolds numbers and stations along a flat plate. Comparisons are made of the density profiles obtained with a total-pressure probe of small frontal opening and by means of an X-ray absorption method and, in a few cases, by using interferometer data.

From Introduction: "In the analysis given herein, which was made at the NACA Lewis laboratory, the expression for eddy diffusivity given in reference 1 is modified in order to account for the effect of kinematic viscosity in reducing the turbulence in the region close to the wall. The effects of variable viscosity and of length-to-diameter ratio are also investigated."

An experimental study is presented of the pressure fluctuations near jet exhaust streams made during unchoked operation of a turbojet engine and a 1-inch-diameter high-temperature model jet and during choked operation of various sizes of model jets with unheated air. The tests for unchoked operation indicate a random spectrum of rather narrow band width which varies in frequency content with axial position along the jet. Pressure surveys from the model tests along lines parallel to the 15 degree jet boundary indicate that the station of greatest pressure fluctuations is determined by the jet velocity and the radial distance, with a tendency of the maximum to shift downstream as either parameter is increased.

"Increasing demands for higher afterburner performance have required operation at progressively higher fuel-air ratios, which has increased the occurrence and intensity of screeching combustion. The onset of screech may be followed by rapid destruction of the combustor shell and other combustor parts. Because of its destructive characteristics, considerable effort has been expended to understand and eliminate screech. NACA work on the screeching combustion problem prior to 1954 is summarized herein" (p. 1195).

Three 1/5-scale models of the Hermes A-3A missile have been flown to determine the effect of rocket-motor operation on the drag corresponding to various altitude and Mach number combinations. The flights covered a Mach number range from 0.5 to 1.8, and ratios of jet-exit static pressure to free-stream static pressure from 0.8 to 1.8. The results indicate that the power-on drag of the missile should be the same as the power-off drag at Mach number 1.3 and slightly less than the power-off drag at Mach number 1.55.

A flight test has been conducted to determine the longitudinal stability and control,characteristics of a 0.133-scale model of the Consolidated Vultee XFY-1 airplane without propellers for the Mach number range between 0.73 and 1.19.

An extensive investigation of the changes of the local and mean heat-transfer coefficients along the pipe length, and some results.

From Summary: "The effects of deflecting full-span, constant-chord, leading-edge flaps, having either round or sharp leading edges, upon the lift, drag, and pitching moment characteristics of a model of an interceptor-type aircraft have been determined experimentally at subsonic and supersonic speeds. Results indicate that the variations of lift with angle of attack and of pitching moment with lift were unaffected by either the shape of the flap leading edge or flap deflection. Deflection of the flaps having either a round or sharp leading edge increased the drag at zero lift at both subsonic and supersonic speeds. In spite of the increase in the drag at zero lift, however, deflection of the flaps increased the maximum lift-drag ratio at subsonic speeds and had no deleterious effect at supersonic speeds."

From Summary: "An investigation was conducted in the Langley 19-foot pressure tunnel on a 0.3-scale model of the Republic RF-84F airplane to determine modifications which would eliminate the pitch-up that occurred near maximum lift during flight tests of the airplane. The effects of high-lift and stall-control devices, horizontal tail locations, external stores, and various inlets on the longitudinal characteristics of the model were investigated. For the most part, these tests were conducted at a Reynolds number of 9.0 x 10(exp 6) and a Mach number of 0.19. The results indicated that from the standpoint of stability the inlets should possess blunted side bodies. The horizontal tail located at either the highest or lowest position investigated improved the stability of the model."

"This investigation was made to determine the effects of 6 degree full-span and 3 degree partial-span leading-edge flaps in combination with chord-extensions or fences on the aerodynamic characteristics of a wing-fuselage configuration with a 45 degree sweptback wing of aspect ratio 4, taper ratio 0.3, and NACA 65A006 airfoil sections. The investigation was made in the Langley high-speed 7- by 10-foot tunnel over a Mach number range of 0.40 to 0.93 and an angle-of-attack range of about -2 degrees to 24 degrees. Lift, drag, and pitching-moment data were obtained for all configurations" (p. 1).

Report presenting an investigation on a transonic bump to determine the aerodynamic characteristics of a series of triangular wings. Four basic triangular-wing plan forms with different aspect ratios, taper ratios, and combinations of tip clipping were tested over a range of Mach and Reynolds numbers. Results regarding angle of attack, drag coefficient, pitching-moment coefficient with lift coefficient, and various curves are provided.

Report presenting an investigation to evaluate the overall performance characteristics of several annular nose inlets in the supersonic wind tunnel at a Mach number of 3.85. The four experimental configurations investigated consisted of a one-cone, a one-cone with low angle cowl, a two-cone, and an isentropic inlet. Results regarding the internal-flow performance, force measurements at zero angle of attack, overall performance comparison at zero angle of attack, and angle-of-attack force measurement are provided.

From Introduction: "The purpose of this report is to present the results of the analytical investigation of the turbine of reference 1 to indicate the extent to which the various turbine losses affect the turbine efficiency over the range of performance."