This technical progress report details 100 Area activities for the time period of May 14 through May 20, 1946.

Report discussing about 400 references pertaining to the hydrodynamic design of seaplanes have been compiled, and the information is presented in the form of abstracts classified under six main headings.

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From Introduction: "The purpose of the present paper is to present results obtained recently relating to the characteristics of a full-span sharp-edge spoiler with an 0.02-chord projection above the wing surface at several chordwise positions and also to the relative effectiveness of the sharp-edge spoiler and a wedge-type spoiler located at the 80-percent-chord line."

Report discussing a particular wing-body combination that is part of a larger investigation to determine the lift, drag, pitching moment, and root bending moments for various configurations. Information about the aerodynamic characteristics at the tail plane is also provided.

Report presenting the air-flow behavior over the wing of an XP-51 airplane including photographs of tufts attached to the wing surface and chordwise pressure distributions. A comparison of tuft studies from flight results are compared with results from wind-tunnel testing. Three types of flow were observed: steady flow, unsteady flow, and break-away flow are provided.

From Introduction: "An analytical evaluation of the effects of inlet losses on the net thrust and the fuel economy of an axial-flow-compressor type turbojet engine with a two-stage turbine is presented herein. The analysis is based on engine performance characteristics that were determined from experiments in the NACA Cleveland altitude wind tunnel (references 1 and 2). The experimental investigation did not include tests in which inlet losses were systematically varied, but the effects of these losses can be accurately estimated from the experimentally determined performance characteristics of the engine."

From Introduction: "An apparatus that gives a quick and an accurate measurement of the rate of discharge has been has been designed by the NACA and is described in this report."

From Summary: "An apparatus for varying effective dihedral in flight by means of servo actuation of the ailerons in response to sideslip angle is described. The results of brief flight tests of the apparatus on a conventional fighter airplane are presented and discussed. The results of an investigation employing the apparatus to determine the tolerable (safe for normal fighter operation) range of effective dihedral on the test airplane are presented."

Report presenting the use of Von Karman's two-dimensional transonic similarity law as applied to drag data of three different thickness wings with NACA 65-series sections and aspect ratios of 7.6 over a range of Mach numbers. The correlation was found to be satisfactory, with results better in the subsonic range than in the supersonic range.

Equations are presented for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of a satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling or in flight at low airspeeds, and to prevent flutter. Examples are presented to show the design features of spring tabs required to solve these problems for airplanes of various sizes.

Experiments were carried out to determine how fast the concentration of suspended material decreases in fumes produced by the hydrolysis of UF/sub 6/ vapor in damp air. The rate of aggregation is a function chiefly of the number of particles per unit gas volume, but depends also on the chemical composition, size and shape of the particles, the temperature and pressure, and the degree of agitation. The rate of settling depends on the weight and shape of the particles and the viscosity of the gas. (W.L.H.)

"A method is presented for calculating the aerodynamic loading, the divergence speed, and certain stability derivatives of wings and tail surfaces of arbitrary plan form and stiffness. Provision is made for using either stiffness curves and root-rotation constants or influence coefficients in the analysis. Computing forms, tables of numerical constants required in the analysis, and an illustrative example are included to facilitate calculations by means of the method" (p. 1).

A method is presented for calculating the aerodynamic loading, the divergence speed, and certain stability derivatives of swept and unswept wings and tail surfaces of arbitrary stiffness. Provision is made for using either stiffness curves and root rotation constants or structural influence coefficients in the analysis. Computing forms, tables of numerical constants required in the analysis, and an illustrative example are included to facilitate calculations by means of the method.

Report presenting an investigation using a single combustor from a 4600-pound-thrust turbojet engine to determine the amount of carbon deposition of AN-F-58 fuels and the effect of carbon formations in the combustor on the altitude operational limits. Three fuel blends conforming to AN-F-58 specification were prepared in order to determine the influence of boiling temperature and of aromatic content on carbon deposition. Results regarding carbon deposition and effect of carbon formations on altitude operational limits are provided.

"The scope of the manual includes discussion and illustration of organization, equipment, training, and methods of employment of the mechanized cavalry reconnaissance troop and its components, designed to simplify and speed training and to facilitate understanding of basic doctrine."

Technical report containing short articles on (1) Determination of physical constants for U233; (2) Determination of decay chain of U233; (3) Extraction of U233; (4) Extracting solvents for uranium; (5) Factors affecting the extraction uranium and thorium by organic solvents, especially ether; and (6) Analysis of ore samples for protoactinium.

From Summary: "An investigation has been conducted on a V-1650-7 engine to determine the cylinder temperatures and the coolant and oil heat rejections over a range of coolant flows (50 to 200 gal/min) and oil inlet temperatures (160 to 2150 F) for two values of coolant outlet temperature (250 deg and 275 F) at each of four power conditions ranging from approximately 1100 to 2000 brake horsepower. Data were obtained for several values of block-outlet pressure at each of the two coolant outlet temperatures. A mixture of 30 percent by volume of ethylene glycol and 70-percent water was used as the coolant."

The problems of static and dynamic longitudinal stability both at high speeds and at low speeds are discussed and data are presented which indicate recent progress made in the solution of these problems.

Report presenting an investigation of the problems of static and dynamic longitudinal stability both at high speeds and low speeds as well as information about progress that has been made to solve these problems. The incorporation of large amounts of sweepback on both the wing and horizontal tail can improve the rate of trim changes and stability. Longitudinal stability has been attained for configurations with a sweep angle of 45 degrees with stall-control devices, but experimental proof is needed for these devices.

A scheme of glucose degradation has been validated by the use of intermediates of known isotopic composition. In this scheme: glucose {yields} lactic acid {yields} CO{sub 2} (C-3,4) + acetic acid {yields} CO{sub 2} (C-2,5) + acetone {yields} iodoform (C-1,6) + acetate (C-1,6; 2,5), it was found that (a) in the oxidation of lactic acid, approximately 4.7% of the acetic acid was oxidized to CO{sub 2}; and (b) under the conditions prescribed, BaCO{sub 3} from the degradation of Ba acetate contained approximately 1.5% of the activity of the methyl group.

This memorandum confirms previous verbal answers to the questions presented by the 234-5 Design group for clarification regarding Specification Letters 234-1, 235-1, 234-2 and 234-3. Testing, plutonium concentration in air, equipment modifications and process control are among items addressed.

Report presenting tests to determine the effects of sweepback angle and aspect ratio on the drag of an NACA 65-009 airfoil at supersonic speeds. The results indicated that for the range of Mach numbers investigated, increasing the sweepback angle and decreasing the aspect ratio reduced the value of the wing drag coefficient.

Report presenting an investigation of the effect of hull length-beam ratio on the hydrodynamic characteristics of flying boats that extend to a length-beam ratio of 20. The results are compared with flying boats having a length-beam ratio of 15. Results regarding longitudinal stability, spray characteristics, take-off performance, taxiing and take-off behavior in waves, landing behavior in waves, and a summary chart are provided.