Memorandum presenting an instrument for recording and indicating the frequency and intensity of aircraft icing conditions to obtain statistical icing data over worldwide air routes during routine airline operations. Data of this type is needed to provide pertinent meteorological information necessary for the optimum design of ice-protection systems. The features that make this particular instrument desirable include the simplicity of operation, freedom from maintenance and operating problems, automatic operation upon encountering an icing condition, visual indications of icing intensity available to the pilot, total weight of 18 pounds, and continuous recorded data.

"Flight icing-rate data obtained in a dense and abnormally deep supercooled stratiform cloud system indicated the existence of liquid-water contents generally exceeding values in amount and extent previously reported over the midwestern sections of the United States. Additional information obtained during descent through a part of the cloud system indicated liquid-water contents that significantly exceeded theoretical values, especially near the middle of the cloud layer. The growth of cloud droplets to sizes that resulted in sedimentation from the upper portions of the cloud is considered to be a possible cause of the high water contents near the center of the cloud layer" (p. 1).

From Introduction: "The auxiliary apparatus described in this paper was constructed to meet this need and has been developed to a point where satisfactory measurements of relative drag can be obtained. In this paper, the apparatus is described and some comparisons are made between the results obtained with this apparatus and the measurements of free-fall, rocket, and supersonic-tunnel techniques."

The effects of water injection on a compressor are presented. To determine the effects of varying water-air ratio, the compressor was operated at a constant equivalent impeller speed over a range of water-air ratios and weight flows. Operation over a range of weight flows at one water-air ratio and two inlet air temperatures was carried out to obtain an indication of the effects of varying inlet air temperature. Beyond a water-air ratio of 0.03 there was no increase in maximum air-weight flow, a negligible rise in peak total-pressure ratio, and a decrease in peak adiabatic efficiency. An increase in inlet air temperature resulted in an increase in the magnitude of evaporation. An analysis of data indicated that the magnitude of evaporation within the compressor impeller was small.

Report presenting an investigation of two large-scale, semispan, wing-fuselage models with the 0.25-chord line swept back 45 degrees to determine and compare the effects of partial-span, double-slotted flaps on the characteristics of a 45 degree sweptback wing with and without camber and twist. A secondary investigation was also conducted to determine the effects of various full-span, leading-edge modifications on the characteristics of the models with and without the flaps.

Report presenting testing of several turbojet engines with both constant- and variable-area nozzles to extend full-scale nozzle performance to higher exhaust-nozzle pressure ratios and to investigate the effects of constant- and variable-area nozzles on turbojet-engine operation. Results regarding the different types of nozzles are provided.

Report presenting flight testing of a missile model with cruciform, triangular, interdigitated wings and tails to determine the longitudinal stability and control characteristics over a range of Mach numbers. Results regarding static stability and damping, control effectiveness, and control hinge moments are provided.

Report presenting an investigation of the applicability of a finite-step method to the calculation of subsonic spanwise load distribution, lift-curve slope, lateral center of pressure, and aerodynamic center of unusual plan forms. The 20-step method was found to generally overestimate the amount of loading at the wing tip, but the lift-curve slope, lateral center of pressure, aerodynamic center, and loading shape generally agreed with lifting-surface results.

Report presenting testing of the effects of the following variables on combustion performance are determined: inlet-air temperature, combustion-chamber-inlet Mach number and pressure, and fuel density and volatility.

Section data obtained from wind-tunnel tests at Mach number 4.04 and Reynolds numbers of about 5.0 times 10 to the 6th power and 8.4 times 10 to the 6th power are presented for 6- and 9-percent-thick symmetrical circular-arc airfoils with 30 percent chord trailing-edge flaps. Pressure distributions, Schlieren photographs, and force and moment coefficients are included.

The Mach number and temperature profiles in jets expanding from convergent and convergent-divergent nozzles are presented for several values of nozzle-exit pressure ratio. The effects of jet temperature, Reynolds number, and humidity on jet spreading are briefly evaluated. The results indicated that the downstream Mach number profiles for a heated jet are slightly narrower than those for a unheated jet, whereas the downstream temperature profiles were unaffected by nozzle temperature change, and that the effects of Reynolds number and humidity were negligible.

Report presenting an investigation at subsonic speeds of a scoop-type air-induction system designed for use at subsonic and supersonic speeds. Measurements of the ram-recovery ratio and static pressures in a scoop-type intake on the upper surface of the fuselage were taken for a large range of mass-flow ratios, angles of attack, and angles of sideslip.

Report presenting a theoretical investigation of an automatic control system with primary sensitivity to normal accelerations as used to control a specific supersonic canard missile. The control system is made up of an integrating servomotor that receives a signal from an accelerometer that is sensitive to normal accelerations of the airframe that it is controlling. The acceleration control system appears to work well for obtaining longitudinal control, but works best when combined with a homing seeker or guidance system for controlling directional space.

From Summary: "This paper supplements a previously published one on the effect of design parameters on ditching characteristics. The supplementary information is based on additional data available from both model tests and full-scale experience. In addition, summary tables compiled from the NACA model ditching investigations are presented."

"An instrument for recording and indicating the frequency and intensity of aircraft icing conditions encountered in flight has been developed by the NACA Lewis Laboratory to obtain statistical icing data over world-wide air routes during routine airline operations. The operation of the instrument is based on the creation of a differential pressure between an ice-free total-pressure system and a total-pressure system in which small total-pressure holes vented to static pressure are allowed to plug with ice accretion. The simplicity of this operating principle permits automatic operation, and provides relative freedom from maintenance and operating problems" (p. 1).

"Values of total drag coefficient were measured for four round-nosed bodies of revolution in free flight at Mach numbers from 0.6 to 1.5 and Reynolds numbers from 10 x 10(6) to 50 x 10(6). The bodies were designed by rounding off the sharp, fineness-ratio-3.56 nose of a previously tested configuration. The nose radii tested were 27.4, 38.7, 80.6, and 100 percent of the maximum body radius and corresponded to values of 0.075, 0.150, 0.650, and 1.000, respectively, for the ratio of nose-sphere frontal area to body frontal area" (p. 1).

Report discusses a procedure for estimating the wing lift coefficient for and spanwise location of the first occurrence of section stall on a swept wing. It has been modified from a method used to calculate the same information for unswept wings. The effects of split flaps, leading-edge modifications, and fences are described.

Report presenting a pilot-opinion survey conducted with a conventional fighter airplane fitted with special servo devices for varying in flight the dihedral effect, static directional stability, and directional damping. Results showing the boundaries that define satisfactory and tolerable lateral oscillatory characteristics are presented.

Effects of humidity during fabric conditioning and during fabrication upon some physical properties of laminates prepared with glass fabric and an unsaturated polyester resin were investigated. Tests on these laminates included the measurement of flexural strength on the diagonal, both dry and after 7 days' immersion in water, specific gravity, resin content, percentage of voids, and total light transmission. Some data were also taken on lengthwise flexural strength.

Memorandum presenting an investigation conducted in the 20-foot free-spinning tunnel on a 1/20-scale model of the McDonnell F2H-3 airplane. The effects of control settings and movement on the erect spin and recovery characteristics of the model were determined for the take-off condition and for the condition with full wing-tip fuel tanks installed.

"A light-source power unit has been developed that provides reliable trigger, and easy synchronization with rotating elements or electric impulses. When used with conventional spark gaps and flash tubes, this power unit provides a light pulse of high intensity and short duration" (p. 1).

Report presenting an aerodynamic investigation in the high-speed 7- by 10-foot tunnel to determine the effects of taper-in-thickness on the aerodynamic characteristics of wings with 35 and 45 degrees of sweepback, aspect ratio 6, and taper ratio 0.60. The wings were tested over a range of Mach numbers.

Report presenting a low-speed wind-tunnel investigation to determine the longitudinal aerodynamic characteristics of a 47.7 degree sweptback wing-fuselage combination with split flaps and several modifications. The lift characteristics, pitching-moment characteristics, drag characteristics, and a comparison with flaps of the slotted type are included.

Report presenting a wind-tunnel investigation of two semispan wing models with 45 degrees of sweepback, an aspect ratio of 5, and a taper ratio of 0.565. One wing had no camber or twist while the other was cambered for a design lift coefficient of 0.4 and twisted to relieve loading at the tip. Results regarding the plane wing, cambered and twisted wing, wing-body combinations, effect of camber and twist, effect of fences, effect of surface roughness, and lift-drag ratio are provided.