Describes the characteristics of fire ants, the damage they cause, and methods for control.

Report discussing performance estimates for several airplanes using General Electric AC-210 ramjet nuclear-powered engines. Assumptions used for designing the engines, radiation shield, and airframe are described. Potential tradeoffs in regards to power and weight reduction are also discussed.

Memorandum presenting a transonic flutter investigation of models of the wing of a current fighter airplane. The models were dynamically and elastically scaled in accordance with criteria which include a flutter safety margin. Results regarding the presentation of data, interpretation of results, wings without leading-edge chord-extensions, and wings with leading-edge chord-extensions are provided.

Report presenting testing of gaseous hydrogen fuel burned in a connected-pipe combustor with a cross section equal to 35 degrees sector of a 28-inch diameter. Eleven shrouded fuel-injector configurations were used to obtain combustion data at specified high-altitude ramjet combustor conditions. Results regarding shroud air blockage, mixing tabs, higher equivalence-ratio burning, injector size, flameholder durability, burner length, combustion efficiency, and temperature profile are provided.

Memorandum presenting an investigation of the steady-state wing loads conducted on a Boeing B-52 airplane over a range of Mach numbers and altitudes. Results regarding flight tests and air-load calculations are provided.

Report presenting testing of specimens of various metals in selected geometric configurations exposed to liquid fluorine under controlled conditions of flow and pressure. None of the samples eroded, decomposed, or exhibited any measurable physical or chemical changes.

"A series of test flights was conducted by the U. S. Navy over a 3- year period to evaluate the effects of icing on the operation of the ZPG-2 airship. In supercooled. clouds, ice formed only on the forward edges of small protuberances and wires and presented no serious hazard to operation. Ice accretions of the glaze type which occurred in conditions described as freezing drizzle adversely affected various components to a somewhat greater extent" (p. 1).

Report discussing a transonic flutter investigation of models of the T-tail of the Blackburn NA-39 airplane. The investigation was made at a variety of Mach numbers at simulated altitudes extending to below sea level. The Mach numbers at which asymmetric flutter and symmetric oscillations occur are presented.

Memorandum presenting an analysis of a large number of liquid-metal-to-air heat-exchanger cores for the nuclear-powered liquid-metal turbojet cycle to determine which types yield the best overall net thrust per total engine weight. The performances of all exchangers considered were initially evaluated at a median condition. The performance of the best of each of the four types was compared with that of a shell-and-tube exchanger with the air flowing through the tubes, operating at the same condition.

Report discussing various inlet design philosophies based on the results of testing at Mach numbers up to 5. The most ideal inlet design was found to be one with combined external-plus-internal compression due to problems noted with both external-only and internal-only inlets.

Control trailing-edge thickness and aspect ratio effect on oscillating hinge-moment and flutter characteristics of flap-type controls. Results regarding damping moments and flutter characteristics and spring moments are provided.

A wind-tunnel investigation was made to determine the effects on the aerodynamic characteristics of a 35 degree swept-wing airplane of applying blowing-type boundary-layer control to the trailing-edge flaps. Flight tests of a similar airplane were then conducted to determine the effects of boundary-layer control on the handling qualities and operation of the airplane, particularly during landing and take-off. The wind-tunnel and flight tests indicated that blowing over the flaps produced large increases in flap lift increment, and significant increases in maximum lift. The use of blowing permitted reductions in the landing approach speeds of as much as 12 knots.

"The increasing importance of high-speed flow leads to similar problems in various fields of research which are summarized in what follows. Typical of all cases is the conversion of high kinetic energy into extreme thermodynamic states with temperatures of several thousand degrees, frequently connected with dissociation and ionization of the gas involved. There is also a characteristic small sensitivity to the processes discussed in the case of gases of low molecular weight (light gases)" (p. 1).

"We consider in this report the determination of the upper limit of critical loads in the case of simultaneous action of a compressive force, uniformly distributed over plane cross sections, and of isotropic external normal pressure on cylindrical or conical shells of circular cross section. As a starting point we use the differential equations for neutral equilibrium of conical shells which have been used for the solution of the problem of stability of conical shells under torsion and under axial compression; upon solution of the problem it is possible to satisfy all boundary conditions, in contrast to the report where no attention is paid to the fulfillment of the boundary conditions, and to the report where only part of the boundary conditions are satisfied by solution of the problem according to Galerkin's method" (p. 1).

Convection is called free is the stresses (including the normal pressure) to which the fluid is subjected at its boundaries do not perform mechanical work, that is, if all the boundaries of the fluid are stationary. The case where this is not true is termed forced convection. It corresponds to the action on the fluid of some mechanical suction pumping the fluid.

From Summary: "The effect of engine momentum on the longitudinal and directional stability of aircraft in steady rolling maneuvers has been investigated. The results presented indicate that the gyroscopic moments produced on the aircraft by a rotating engine in rolling maneuvers can have an appreciable effect on the range of rolling velocities for which longitudinal or directional instability might occur."

From Introduction: "First, an analysis of loads transmitted to the hub by balanced blades will be given. In the second section, the additional loads transmitted to the hub in a direction normal to the plane of rotation of the blades by imbalances in a rotor are derived. In the entire analysis, the results are given in terms of the forces transmitted to the hub by a single rotating helicopter blade in flight, and these are regarded as known or given."

Report presenting an investigation in the 2- by 2-foot transonic wind tunnel to determine the aerodynamic effects of fixing boundary-layer transition in a forward location on two unswept-wing models differing only in size and with unswept wings of aspect ratio 3.09 with sharp leading edges. Results regarding effects of fixing transition and wall effects in the Ames 2- by 2-foot transonic wind tunnel for an unswept-wing-body model are provided.

Note presenting the minimum thickness of the oil film as used as a basic variable in performance curves of plain journal bearings under steady load. The load capacity and the predicted film thickness at the hook point of the friction curves are shown to correlate with the peak-to-valley values of surface roughness when misalignment is absent.

Note presenting hot-wire anemometer measurements of the turbulent shearing stress in a turbulent boundary layer on a yawed flat plate. The measured velocity profiles are used to calculate the shear distribution and the result is compared with the result of experimental shear measurements.

Report presenting an experimental study of the drag of flat plates and cylinders in the slipstream of a hovering rotor. The dynamic pressure profile of the slipstream for stations close to the rotor was characterized by low or slightly negative values in the center, a rise to a peak near the edge of the slipstream, and a rapid decrease to small negative values farther from the center. Results regarding the drag-to-thrust ratio, ratio of percent thrust loss to percent blocked area, and drag coefficients are provided.

Note presenting a method for the design and analysis of two-dimensional subsonic-flow passages with isentropic nonviscous flow. The method is based on the relation between the pressure change across a stream tube and the centrifugal force resulting from the curvature of the flow. In an example, the method was applied to the design of an expanding elbow at each of two Mach numbers.

An approximate theory is developed for predicting the rate of heat transfer to the stagnation region of blunt bodies in hypersonic flight. Attention is focused on the case where wall temperature is small compared to stagnation temperature. The theoretical heat-transfer rate at the stagnation point of a hemispherical body is found to agree with available experimental data. The effect of yaw on heat transfer to a cylindrical stagnation region is treated at some length, and it is predicted that large yaw should cause sizable reductions in heat-transfer rate.

Report presenting an experimental investigation of the equivalence relationship and the related theory for lifting forces proposed by transonic slender-body theory. Two different models with different dimensions are tested over a range of Mach numbers. Results regarding flow equivalence at sonic speed, Mach number range of equivalence, and lifting pressures at transonic speeds are provided.