Technical report with short reports from the (1) Physics Section I; (2) Physics Section II ; and (3) Physics Section III.

Abstract. Measurements were made to determine the effect of thermal cycling on heat transfer from slug to jack using a slug with a sand blasted surface. The value of the transfer coefficient h decreased from initial values ranging from 10 to [formula], to values and [formula] after 1700 cycles, and to a range of 0.15 to 0.45 [formula] after 3200 cycles. Comparisons are made with the results found for slugs with different surfaces.

This report follows experiments on the acute effects of 200 kv X-ray treatments on chickens in a series of 200 animals exposed to doses of 2 r to 1200 r, with an additional 100 chickens.

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).

A major problem encountered in the Manhattan Project was the protection of workers against damage resulting from acute or chronic exposure to external radiation. The problem of how to detect evidence of damage following exposure to total body radiation led to this study. These studies were conducted between January, 1942 and November, 1945. Three groups of persons were employed in this study. The first group of eight individuals harboring incurable neoplasms which was not extensive enough to influence general health, these patients were treated with 400 KV x-radiation while sitting in a wooden chair, doses were 27, 60, and 120r. Three persons having generalized illnesses chronic in nature were given total body radiation using 200 KV X-rays in multiple exposures totaling 100, 300, and 500r. A third group of normal volunteers from personnel of the Metallurgical Laboratory were treated with 200 KV x-rays in three divided doses totaling 21 r. Changes in peripheral blood in the fourteen individuals is reported. In group 1 the most persistent abnormality noted was a diminution in the number of lymphocytes after completion of the treatment. In group 2 a depression in the lymphocytes was also the most marked single change. In group 3 no …

Memorandum presenting wind-tunnel tests to determine the aerodynamic characteristics of a 15-percent- and a 35-percent-chord plain trailing-edge flap on the NACA 0006 airfoil section. Simultaneous measurements of section lift, drag, and pitching moment were made over a range of Mach numbers, angles of attack, and flap deflections.

Report presenting the drag of a series of complete airplane-like configurations and their components at transonic velocities using the free-fall method. The configuration tested in this report has a 45 degree sweptback wing of aspect ratio 4.1 mounted forward of the maximum diameter of a 10-inch-diameter body of fineness ratio 12 equipped with stabilizing tail fins. Results are presented as curves showing the variation of drag coefficient with Mach number for the complete configuration and for each component.

Report presenting an investigation using a 4600 pound-thrust turbojet engine as part of a program to determine the comparative performance of fuels conforming to specifications AN-F-58 and AN-F-32. Results regarding the altitude performance, altitude low-speed blow-out limits, idling limits of fuel-metering control, altitude windmilling starts, carbon-deposition rates, and iron oxide contamination are provided.

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.

Report discussing testing using two rocket-propelled models to test the jettisonable-nose method of pilot escape. The nose was jettisoned successfully on the second attempt and the accelerations produced were found to be within human tolerance. The first test ended with a collision of the nose and wing, indicating that this is a possible risk during power-on flight.

Report presenting a wind tunnel investigation to determine the downwash angles, dynamic pressure loss, and wake width behind wings with sweep angles of 45, 30, and 0 degrees. Results indicated that the spanwise distribution of downwash was affected by sweep in a manner similar to span loading, increased toward the root by sweepforward and toward the tip by sweepback.

Tests were made in the Langley 7 by 10 foot tunnel on a model of a fighter-type airplane with external stores. The data obtained is presented and compared to flight-test results to determine the feasibility of estimating flight buffet Mach number from tunnel data.

Report presenting a survey of two-dimensional data on trim changes near maximum lift resulting from deflection of various types of leading-edge and trialing-edge high lift devices. Results regarding pitching-moment coefficients, pitching-moment increments, and maximum lift coefficients are provided.

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.

Report presenting wind-tunnel testing of submerged air inlets on the fuselage of a scale model of a typical fighter-type airplane. The results are presented for ramp plan forms with parallel and with diverging walls and show the effect of the duct-entrance location, internal ducting efficiency, and deflectors.

Memorandum presenting wind-tunnel tests of a semispan model of an unswept wing of aspect ratio 4 and taper ratio 0.5 at Mach numbers up to 0.94 to determine its aerodynamic characteristics as influenced by Mach number, Reynolds number, and modification of the basic diamond profile by rounding the ridge. Lift, drag, and pitching-moment data are presented for a range of Reynolds and Mach numbers. The results indicated that no severe static-longitudinal-stability problems up to Mach number 0.94.

Report presenting testing of low-aspect-ratio triangular-plan-form lifting surfaces located on conical and cylindrical portions of a body have been determined at Mach number 1.2 and several subsonic speeds to determine if the aerodynamic characteristics of these surfaces at supersonic speeds could be improved by locating them in the subsonic conical-flow field. Results regarding lift and drag coefficients and lift-curve slopes are provided.

Memorandum presenting the results of measurements of gust and draft velocities within thunderstorms at a selected air field over a 5-day period. They are also compared to previous flights.

"In order to understand the operation and the interaction of jet-engine components during engine operation and to determine how component characteristics may be used to compute engine performance, a method to analyze and to estimate performance of such engines was devised and applied to the study of the characteristics of a research turbojet engine built for this investigation. An attempt was made to correlate turbine performance obtained from engine experiments with that obtained by the simpler procedure of separately calibrating the turbine with cold air as a driving fluid in order to investigate the applicability of component calibration. The system of analysis was also applied to prediction of the engine and component performance with assumed modifications of the burner and bearing characteristics, to prediction of component and engine operation during engine acceleration, and to estimates of the performance of the engine and the components when the exhaust gas was used to drive a power turbine" (p. 1).

In order to obtain a correlation of drag data from wind-tunnel and flight tests at high Mach numbers, a typical pursuit airplane, with the propeller removed, was tested in flight at Mach numbers up to 0.755, and the results were compared with wind-tunnel tests of a 1/3-scale model of the airplane. The tests results show that the drag characteristics of the test airplane can be predicted with satisfactory accuracy from tests in the Ames 16-foot high-speed wind tunnel of the Ames Aeronautical Laboratory at both high and low Mach numbers. It is considered that this result is not unique with the airplane.

"The results of analytical studies of tail-pipe-burning, water-injection, and bleedoff methods of thrust augmentation are presented that provide an insight into the operating characteristics of these augmentation methods and summarizes the performance that may be obtained when applied to a typical turbojet engine. A brief description of the principles of operation of each augmentation method is given, together with curves that illustrate the effects of the principal design and operating variables of the augmentation system on the thrust and the liquid consumption of the engine. The necessity of designing tail-pipe burners with a low burner-inlet velocity, a low burner drag, and a high diffuser efficiency in order to obtain a high thrust augmentation and to minimize the loss in engine performance during nonburning operation is illustrated" (p. 593).

Report presenting flight tests conducted to measure the lateral-control characteristics of an airplane, equipped with a lateral-control system, in which as the flaps are lowered the ailerons droop and a gradual transition of lateral control from ailerons to spoilers takes place. The variation of maximum rolling velocity with lateral stick movement as obtained in abrupt rudder-locked rolls was satisfactorily smooth except when control was by spoiler alone.

This document is a March 1949 Ad Interim Report on the development of a high-speed, low-sensitivity calorimeter at the Mound Laboratory. This calorimeter is a zero-compensating, thermocouple, twin type. The outside diameter of the aluminum tubing was machined for a slip fit into the glass test tube. Prior to assembling in the test tube, an aluminum plug was pressed in it midway from the ends. A groove was also milled on the outside down to the plug, and a copper-constantan thermocouple was secured in the groove after assembly. A single layer of aluminum foil was used to reduce radiation effects, and stray air currents were excluded with a cotton plug. The two arms of the calorimeter were placed in a three-liter beaker filled with water. The constantan leads of the two thermocouples were soldered together to make them compensating. The copper leads were connected to a L & N potentiometer, and a L & N galvanometer was also used. The potentiometer-galvanometer circuit was so connected that before each reading of the EMF of the thermocouples, the thermal EMF in the circuit could be accounted for. The galvanometer was then mounted on a heavy brass plate. The data show that when …

During the dissolution in nitric acid of uranium metal which has been irradiated in a pile, radio-iodine (8.0 day) and radio-xenon (5.3 day) are liberated along with the oxides of nitrogen. Since in the plant these gases are discharged into the atmosphere, the presence of the activities (particularly radio-iodine because of its greater chemical reactivity) presents a physiological hazard. As a consequence, the cooling period (that is, the time between the discharge of the metal from the pile and the dissolution of the metal in nitric acid for the extraction of the product) should be sufficiently long so that the activities will have decreased through decay to the point where their concentrations in the atmosphere will not exceed 2.5 {times} 10{sup {minus}13} curies/cc* and 5 {times} 10{sup {minus}11} curies/cc* for radio-iodine and radio-xenon, respectively. A study was made of the existing information concerning the liberation of iodine and xenon during the dissolution of the metal and the information was summarized in a memorandum. At that time it was apparent that radio-iodine would present the greater hazard, and that very little was known about the factors governing the liberation of iodine during the metal dissolution. For this reason, an investigation of …