From Summary: "The effects of ice formations on the section lift, drag, and pitching-moment coefficients of an unswept NACA 65A004 airfoil section of 6-foot chord were studied.. The magnitude of the aerodynamic penalties was primarily a function of the shape and size of the ice formation near the leading edge of the airfoil. The exact size and shape of the ice formations were determined photographically and found to be complex functions of the operating and icing conditions."

"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).

Note presenting a simplified method for determination of the critical height of three-dimensional roughness particles required to promote premature transition of a laminar boundary layer on models of airplanes or airplane components in a wind tunnel with zero heat transfer. The method has been applied to various types of configurations in several wind-tunnel investigations.

"An empirical relation has been obtained by which the change in drag coefficient caused by ice formations on an unswept NACA 65A004 airfoil section can be determined from the following icing and operating conditions: icing time, airspeed, air total temperature, liquid-water content, cloud droplet impingement efficiencies, airfoil chord length, and angles of attack. The correlation was obtained by use of measured ice heights and ice angles. These measurements were obtained from a variety of ice formations, which were carefully photographed, cross-sectioned, and weighed" (p. 1).

"Data and analyses are presented on the relative frequencies of occurrence and severity of icing cloud layers encountered by jet aircraft in the climb and descent phases of flights to high altitudes. Fighter-interceptor aircraft operated by the Air Defense Command (USAF) at bases in the Duluth and Seattle areas collected the data with icing meters installed for a 1-year period. The project was part of an extensive program conducted by the NACA to collect Icing cloud data for evaluating the icing problem relevant to routine operations" (p. 1).

"The amount of water in cloud droplet form ingested by a full-scale supersonic nose inlet with conical centerbody was measured in the NACA Lewis icing tunnel. Local and total water impingement rates on the cowl and centerbody surfaces were also obtained. All measurements were made with a dye-tracer technique" (p. 1).

Report presenting an exploratory wind-tunnel investigation to determine the lift effects of blowing from nacelles over the upper surface of flaps on a model with a delta wing of aspect ratio 3. The results indicate that the values of jet-circulation lift coefficient larger than the jet reaction were produced with blowing over flaps fro nacelles mounted above the wing. Results regarding lift coefficients, pitching-moment coefficients, and drag coefficients are provided.

From Summary: "Ward's slender-body-theory formula for zero-lift drag contains three integrals plus a base-drag term. Two of these integral terms depend only upon the cross-sectional area distribution of the body. The third integral term depends only upon the body shape and axial slopes at the base of the body. This term is neglected in the transonic area rule because in many cases it is zero; however, there are also many cases in which it is not zero. This paper examines the term for the possibility of drag reduction for a particular case."

Note presenting analytical results obtained for boundary-layer mass flow, momentum, total-temperature, and total-pressure recovery ratios of a scoop inlet with a height equal to the boundary-layer thickness and operating in a turbulent boundary layer, for flat and conical surfaces with wall cooling. The results indicate that design of boundary-layer intake devices or diverters must reflect the effects of wall cooling by either variable or compromised size.

Report presenting a single, ordinary, nonlinear differential equation of second order that can be used for determining entry into an exponential planetary atmosphere. The reduced equation includes various terms, some of which represent the gravity force, the centrifugal acceleration, and the lift force. A number of solutions for lifting and nonlifting vehicles entering at various initial angles are obtained from the complete nonlinear equation.

In this study in which an airplane simulator with one degree of freedom (pitch) was used, results were determined for three conditions of airplane dynamics. For an undamped natural frequency of 1/2 cps with a damping ratio of 0.18 and for an undamped natural frequency of 1 cps with a damping ratio of 0.11, moderate longitudinal stick forces and displacements were desired.

Report presenting flight test data obtained from a large swept-wing bomber airplane in flight through rough air at 5,000 feet to determine the effects of vertical translation and pitching motions on the angles of attack of the wing and tail. The results indicate that the motions, particularly the pitching motions, significantly amplify the angles of attack of the wing and tail for the test airplane.

Note presenting flight tests conducted with a medium-size single-rotor helicopter, of which one blade was equipped with strain gages, to determine the relative effects of atmospheric turbulence and moderate maneuvers on the periodic rotor blade moments. The results indicate no significant increase in the total blade moments due to atmospheric turbulence of moderate pull-up maneuvers which produced center-of-gravity acceleration increments of less than about 0.15g. Results regarding moment records, maximum vibratory moments, harmonic analysis of moment records, and applicability of NACA helicopter VGHN recorder surveys are provided.

Report presenting heat-transfer measurements made in turbulent flow at a variety of Mach and Reynolds numbers through the use of an axially symmetric annular nozzle consisting of an inner shaped center body and an outer cylindrical sleeve. The results are presented as Stanton number and recovery factor as a function of Reynolds number. Stanton number was found to decrease with an increase in Reynolds number and usually decreases with an increase in Mach number.

Report presenting a method that can be used at high supersonic Mach numbers for calculating the flutter speed of wings with camber in their deflection modes. It is used to calculate the flutter speed of some wings that had been tested at Mach numbers of 1.3 and 3.0. Theoretical comparisons of the tested wings are also provided.

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."

Report presenting an investigation of normal forces produced by several skewed nozzles and a series of ejectors with skewed shrouds discharging into quiescent air as conducted with cold air at jet total-pressure ratios up to 6.5. Nozzles were terminated at angles of 30 degrees, 45 degrees, 60 degrees, and 75 degrees relative to the normal plane. Results regarding basic data, effect of skew angle and indentation, and effect of a skewed shroud are provided.

Note presenting heat-transfer rates at the stagnation point of 1.0-inch-diameter glass spherical models in shock-tube flows in air which correspond to free-flight conditions between Mach numbers of 6.4 and 13.9 with stagnation temperatures up to 7900 degrees R. The heat-transfer rates were determined from measurements of the surface-temperature change with time of a thin-film-platinum resistance thermometer.

Report presenting an investigation to determine the effect of modifications made in the propulsion system of a single-engine airplane to substantially reduce its external noise, and, thereby, to evaluate the significance of the external noise level of an airplane with regard to the problem of its detection by ground observers.

Report presenting a study of the effect of the frequency of the lowest wing structural mode on the airplane center-of-gravity dynamic-response factor was made my employing simplified transfer functions.

Report presenting an investigation with two purposes: to obtain a simplified calculation technique for replacing complicated automatic computer calculations and to obtain experimental data for single droplets vaporizing at pressures greater than 1 atmosphere and to check the histories against experimental data.

Report presenting an experimental investigation to determine the effects of planing in a wake on the forces of a planing surface and to locate desirable positions in the wake with regard to the lift and lift-drag ratio of the planing surface. Two combinations of hydro-skis were tested: one with two in tandem and one with three arranged with one hydro-ski in the front and two in the back. Results indicated that the rear hydro-ski in tandem arrangement could have large increases in lift coefficient and small improvements in lift-drag ratio compared with the regular configuration.

Report presenting an investigation conducted on the helicopter test tower to determine experimentally the low tip Mach number stall and high tip Mach number drag divergence characteristics of a helicopter rotor with an NACA 0009 tip airfoil section. Results regarding rotor hovering performance, rotor-blade pitching moments, rotor profile-drag torque, and a comparison with two-dimensional drag-divergence data are provided.

Note presenting a model with an inverted-V transverse shape and a dead-rise angle of -20 degrees as part of a study of hydrodynamic impact loads on chine-immersed bodies. A series of fixed-trim impacts of the inverted-V model were made in smooth water over a wide range of trim and initial flight-path angles at a beam-loading coefficient of 19.15 with a few impacts at beam-loading coefficients of 27.90 and 36.07. The data are presented in tables and in figures as variations of loads and motions (in coefficient form) with time, trim angle, and flight-path angle.