Group 10 - The following items were shipped to Scioto Laboratory: 6 Thyratron Heater Controls (TR-1-A), 2 Switch Boxes (for P & E), 1 Log Amplifier (AM-1); 1 Pulse Generator (PG-1-B). The following are completed, tested, and awaiting transportation: 3 Two-Input B-wall Mixers (MX-2-A), 1 Pulse Generator (PG-1-B),1 Regulation Checker (RC-1) (for plating control power supplies), 1 Preamplifier (AM-2) (for Berkeley decimal scaler). The following are under construction: 6 Pulse Generators (PG-1-B) (for Health Division) (EO-508) 90%, 10 Switch Boxes (8 for P & E, Scioto, 2 for P& E, "T" Building) 85%, 6 Junction Boxes (for P&E, "T" Building, EO-486) 90%, 2 Four-Input G. M. Mixers. One on EO-17, one from Unit III. The mixers have been finished and tested for some time. The scalers (Nuclear Instrument Model 161-G) have just been received and are being modified for use with the mixers. A prototype preamplifier for the Berkeley decimal scaler was constructed and tested. Group 11 - A special pulse generator having output pulses fixed in time, and adjacent pulses variable in time with respect to the fixed pulse is under development. An initial mock-up of such a generator showed promise in that the variable pulses could be shifted …

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Abstract: "Crystal system, crystal habit, and principal refractive indices, of uranyl hydrogen phosphate tetrahydrate, uranyl ammonium phosphate trihydrate, and uranyl phosphate tetrahydrate are reported. A procedure for differentation of these three compounds using this data was developed."

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From Introduction: "The aerodynamic heating problem assumes considerable importance at high-supersonic speeds. Sanger and Bredt (reference 1) have calculated the high-speed aerodynamic forces and equilibrium surface temperature at extremely high altitudes where the molecular mean free path is large (free-molecule-flow region) compared with a characteristic body dimension. The theoretical investigation of Lees (reference 2) on the stability of the laminar boundary layer in compressible flow indicates that the laminar boundary layer is completely stable at all Reynolds numbers at supersonic speeds for a sufficiently low ratio of surface temperature to stream temperature."

"An investigation was conducted to determine the longitudinal- and lateral-stability characteristics of a 0.5-scale model of the Fairchild Lark missile. The model was tested with 0 deg and with 22.5 deg of roll. Three horizontal wings having NACA 16-009, 16-209, and 64A-209 sections were tested. Pressures were measured on both pointed and blunt noses" (p. 1).

This report details events of importance as reported by the Hanford Operations Office for the week ending September 28, 1949.

From Summary: "An investigation has been conducted with the Langley helicopter tower to obtain basic performance and control characteristics of the Raman rotor system. Blade-pitch control is obtained in this configuration by utilizing an auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a range of wind velocities from 0 to 30 miles per hour. The control characteristics and the transient response of the rotor to various control movements were also measured."

Report presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of a 45 degree sweptback horizontal-tail model of aspect ratio 2 and a comparison of these results with results for a model of the same aspect ratio with an unswept hinge line. Results regarding the lift and hinge-moment parameters, static longitudinal stability, effect of Reynolds number, effect of standard roughness, effect of removing elevator nose seal, and visualization of the air flow are provided.

The following document analyzes studies to test the use of asphalt as a fast neutron moderating substance to be incorporated as a part of a pile shield.

Report presenting the results of a wind-tunnel investigation of the effects of variation of trailing-edge angle and leading-edge radius on the aerodynamic characteristics of a 10-percent-chord-thick airfoil section at a range of Mach numbers.

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Report presenting an altitude-chamber investigation to determine the altitude performance characteristics of the British Rolls-Royce Nene II turbojet engine with a standard 18.75-inch-diameter jet nozzle. Results regarding the simulated flight performance and generalized performance across other altitude and pressure characteristics are provided.

"The studies of this report were made to indicate the thermal stability at elevated temperatures of fluorocarbons similar to the hexadecafluoroheptane" (p. 4).

"Measurements were made, in dives to transonic speeds, of the static-pressure position error at a distance of one chord ahead of the McDonnell XF-88 airplane. The airplane incorporates a wing which is swept back 35 deg along the 0.22 chord line and utilizes a 65-series airfoil with a 9-percent-thick section perpendicular to the 0.25-chord line. The section in the stream direction is approximately 8-percent thick. Data up to a Mach number of about 0.97 were obtained within an airplane normal-force-coefficient range from about 0.05 to about 0.68" (p. 1).

Report presenting free-flight investigations conducted on four 16-inch-diameter ramjet units to determine the performance at high subsonic and supersonic velocities. Data for evaluating the performance were obtained from radio-telemetering and radar-tracking equipment. Results regarding combustion performance, diffuser total-pressure recovery, thrust coefficient, and external drag coefficient are provided.

Memorandum presenting flight tests with a fighter airplane to study the effect of boundary-layer suction aft of the shock wave on airfoil drag at supercritical Mach numbers and high Reynolds numbers. Airfoil chord force was determined from pressure-distribution measurements obtained at a range of Mach numbers at steady dives. Results of the tests showed no measurable effect of suction for the suction coefficient available.

Report presenting a low-speed wind-tunnel investigation to determine the lateral control characteristics of extensible wing-tip ailerons on an untapered semispan wing with two configurations; one was unswept and had an aspect ratio of 3.13 and the other was swept back 45 degrees and had an aspect ratio of 1.59. Results regarding the plain-wing aerodynamic characteristics and lateral control characteristics are provided.

This monthly report details 100 Area technical activities of the Physics Group for the month of August 1949.

Report presenting measured pressure over airfoils at Mach number 1, with subsonic velocities at the nose and supersonic velocities throughout the rear portion, are analyzed by comparison with calculations for similar cases. Results regarding the theoretical basis of approximation, comparison of Prandtl-Meyer flow with measurements, comparison of linear-velocity extrapolation with measurements, and effect of boundary layer upon airfoil pressures are provided.

Report presenting an investigation conducted to determine the effects of increased gas temperatures on the performance of cast Vitallium blades in a turbojet engine. Results regarding the experimental investigation and metallurgical investigation are provided.

In order to provide engineers interested in rotating-wing aircraft, but with no specialized training in stability theory, some understanding of the factors that influence the flying qualities of the helicopter, an explanation is made of both the static stability and the stick-fixed oscillation in hovering and forward flight in terms of fundamental physical quantities. Three significant stability factors -- static stability with angle of attack, static stability with speed, and damping due to a pitching or rolling velocity -- are explained in detail.

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"The recent experiments by Jakob and Erk, on the resistance of flowing water in smooth pipes, which are in good agreement with earlier measurements by Stenton and Pannell, have caused me to change my opinion that the empirical Blasius law (resistance proportional to the 7/4 power of the mean velocity) was applicable up to arbitrarily high Reynolds numbers. According to the new tests the exponent approaches 2 with increasing Reynolds number, where it remains an open question whether or not a specific finite limiting value of the resistance factor lambda is obtained at R = infinity. With the collapse of Blasius' law the requirements which produced the relation that the velocity in the proximity of the wall varied in proportion to the 7th root of the wall distance must also become void" (p. 1).