This report presents the results of tests conducted to determine the effect of different amounts and kinds of cowling on the performance and cylinder temperatures of a standard Wright J-5 engine. These tests were conducted in conjunction with drag and propeller tests in which the same cowlings were used. Four different cowlings were investigated varying from the one extreme of no cowling on the engine to the other extreme of the engine completely cowled and the cooling air flowing inside the cowling through an opening in the nose and out through an annular opening at the rear of the engine. Each cowling was tested at air speeds of approximately 60, 80, and 100 miles per hour.

From Summary: "This report presents the results of flight test of the Pitcairn "PCA-2" autogiro. Lift and drag coefficients with the propeller stopped have been determined over approximately a 90 degree range of angles of attack. Based on the sum of fixed-wing and swept-disk areas, the maximum lift coefficient is 0.895, the minimum drag coefficient with propeller stopped is 0.015, and the maximum l/d with propeller stopped is 4.8. Lift coefficients were found also with the propeller delivering positive thrust and did not differ consistently from those found with propeller stopped. Curves of gliding performance included in this report show a minimum vertical velocity of 15 feet per second at an air speed of 36 miles per hour and a flight-path angle of -17 degrees. In vertical descent the vertical velocity is 35 feet per second."

"The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom were determined. The problem resolves itself into the solution of certain definite integrals, which were identified as Bessel functions of the first and second kind, and of zero and first order. The theory, based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing section theory relating to the steady case" (p. 291).

Abstract: "The advantages of high scaling ratios in counting random pulses are discussed. The mechanism of the basic circuit used in the Columbia University scaling circuits is described. The difficulties experienced in the performance of the earlier circuits are indicated and modified circuits to eliminate these difficulties are given. Precautions that must be observed in carrying out the constructional details are suggested. The complete circuit and specifications are given in detail for a Scale of 128 for use with linear-amplifier systems" (p. 1).

"An investigation has been conducted to determine whether three-dimensional flows may be utilized in axial-flow fan and compressor rotors so that the spanwise load distribution may be varied to obtain high pressure rise. Two rotors, one with approximately uniform and one with solid-body downstream tangential-velocity distributions, were designed and tested at the design blade angle" (p. 1).

An altitude-wind-tunnel investigation of the performance of AN-F-58 and AN-F-32 fuels in an experimental turbojet engine was conducted over a range of simulated altitudes and flight Mach numbers. Combustion efficiencies obtained with AN-F-58 and AN-F-32 fuels were approximately equal. The minimum-speed altitude operational limit was essentially the same with either AN-F-58 or AN-F-32 fuel. Starting characteristics of the two fuels were approximately the same at low wind milling speeds. Visual observation showed no apparent differences in the carbon-deposition rates of AN-F-58 and AN-F-32 fuels.

Memorandum presenting an approximate method for the estimation of the properties of the incompressible laminar boundary layer on a flat plate in the slip-flow region using Karman's momentum method. At equivalent stations, the total thickness and the skin friction of a slipping boundary layer are less than that of the normal boundary layer at the same Reynolds number.

From Introduction: "An investigation of the high-speed aerodynamic characteristics of a modified delta wing in combination with a fuselage was conducted in the Langley high-speed 7- by 10-foot tunnel. The model was tested on the sting support system through a Mach number range of 0.40 to 0.90 with both free and fixed transition. Because of the nature of the transition effect, the results seemed to be of the general interest and are presented in the present paper."

"An investigation of a 1/24-scale dynamically similar model of the Boeing B-47 airplane was made to determine the ditching characteristics and proper ditching technique for the airplane. Various conditions of damage, landing attitude, flap setting, and speed were investigated. The behavior of the model was determined from visual observations, motion-picture records, and time-history deceleration records. The results of the investigation are presented in table form, photographs, and curves" (p. 1).

Report discussing an investigation of the rolling effectiveness at transonic and supersonic speeds on a 38.1 degree sweptback tapered wing with NACA 0010-64 airfoil sections and partial-span ailerons of true contour with a modified flt-side blunt trailing-edge shape. The variation of Reynolds number with Mach number and the control effectiveness is provided.

"Investigations have been made in flight and in wind tunnels to determine which components of turbojet installations are most critical in icing conditions, and to evaluate several methods of icing protection. From these studies, the requirements necessary for adequate icing protection and the consequent penalties on engine performance can be estimated. Because investigations have indicated that the compressor-inlet screen constitutes the greatest icing hazard and is difficult to protect, complete removal or retraction of the screen upon encountering an icing condition is recommended" (p. 1).

Report presenting a preliminary analytical evaluation of the air and fuel specific-impulse characteristics of magnesium and magnesium-octene-1 slurries. Adiabatic combustion flame temperature, air specific impulse, and fuel-weight specific impulse are given for each fuel.

The following document focuses on the study of the absorption spectra of americium chloride. Large samples and a spectrograph of great dispersion were used.

From Introduction: "The Ames Aeronautical Laboratory has in progress an experimental investigation of the aerodynamic characteristics of wings of interest in the design of high-speed fighter aircraft. This program included an investigation in the Ames 6-by 6-foot supersonic wind tunnel at both subsonic and supersonic Mach numbers of a wing-body combination having a 3-percent-thick, unswept, tapered wing with circular-arc sections and an aspect ratio of 3.1 (reference 1).

Report presenting testing of rocket-powered models at supersonic speeds to determine some of the surface conditions on the zero-lift drag of fin-stabilized parabolic bodies of revolution. Two types of models and three types of surface roughness were tested. Results regarding mean-drag coefficients, side-pressure coefficients, and total-drag coefficients are provided.

"A modified triangular wing of aspect ratio 2.53 having an airfoil section 3.7 percent thick at the root and 5.98 percent thick at the tip was designed in an attempt to improve the lift and drag characteristics of triangular wings. Free-flight drag and stability tests were made using rocket-propelled models equipped with the modified wing. The Mach number range of the test was from 0.70 to 1.37" (p. 1).

Report discussing the details of a radiation burst in a spherical reactor using plutonium nitrate fuel that occurred on November 16, 1951 at Hanford Works.

Two methods for calculating the *reduction in η due to spectral hardening have been used. In the first method it is assumed that the absorption cross section of U-238 is l/v. This indicates no change in η within the error of the calculation. In the second it is assumed that the scattering cross section of uranium is constant. A decrease in η of 3.0% at the centerline of the slug is indicated by this calculation. The assumption U-238 is a l/v absorber is regarded as the most reasonable of the two.

From Summary: "An experimental investigation has been made in the Langley stability tunnel to determine the low-speed yawing, pitching, and static stability characteristics of a 1/10-scale model of the Grumman F9F-9 airplane. Tests were made to determine the effects of duct-entrance-fairing plugs on the static lateral and longitudinal stability characteristics of the complete model in the clean condition. The remaining tests were concerned with determining tail contributions as well as the effect of duct-entrance-fairing plugs, slats, flaps, and landing gear on the yawing and pitching stability derivatives. These data are presented without analysis in order to expedite distribution."

This volume continues the NACA study of combustion principles for aircraft propulsion. The various aspects of combustion pertinent to jet engines are organized and interpreted with quite extensive information, particularly for basic or fundamental. subject matter. The report concerns only air-breathing engines and hydrocarbon fuels, and not rocket engines and high-energy fuels.

Measurement of radioactive carry-over was made on borax III operating at 300 psig and at power levels ranging from 4 to 14 mv. Decontamination factors of from 1.5 x 104 (at 14 mv) were obtained. These data are in essential agreement with those predicted by previous laboratory experimental work.

Memorandum presenting an experimental investigation to determine the effect on drag of applying the moment-of-area-rule modifications to wing-body combinations with various wing plan forms. The effect of mounting air-to-air type missiles on the wing-mounted bodies of revolution which are part of the moment-of-area-rule modification was also investigated.

Transonic flutter derivatives for unswept wing control surface configurations determined by pressure cell measurements. The control surfaces were mounted on a wing with an aspect ratio of 3, a taper ratio of 0.6, and a wing-thickness ratio of 0.06. Results regarding aerodynamic balance, vortex generators, splitter-plate configurations, and wedges are provided.

Report presenting a determination of transonic flutter characteristics from pressure cell measurements on control surfaces sinusoidally oscillated at an amplitude of plus or minus 1.08 degrees at frequencies from 5 to 30 cycles per second. Various control-surface configurations were investigated, including internal and external aerodynamic balance, vortex generators, a splitter-plate type of control surface, and superposition of triangular shaped wedges or tetrahedra along the rear portion of the control-surface chord.