From Summary: "The historical development of NACA airfoils is briefly reviewed. New data are presented that permit the rapid calculation of the approximate pressure distributions for the older NACA four-digit and five-digit airfoils by the same methods used for the NACA 6-series airfoils. The general methods used to derive the basic thickness forms for NACA 6 and 7-series airfoils together with their corresponding pressure distributions are presented. Detail data necessary for the application of the airfoils to wing design are presented in supplementary figures placed at the end of the paper. The report includes an analysis of the lift, drag, pitching-moment, and critical-speed characteristics of the airfoils, together with a discussion of the effects of surface conditions. Available data on high-lift devices are presented. Problems associated with lateral-control devices, leading-edge air intakes, and interference are briefly discussed, together with aerodynamic problems of application."

"The cavitation in nozzles on airfoils of various shape and on a sphere are experimentally investigated. The limits of cavitation and the extension of the zone of the bubbles in different stages of cavitation are photographically established. The pressure in the bubble area is constant and very low, jumping to high values at the end of the area. The analogy with the gas compression shock is adduced and discussed" (p. 1).

Technical report describing two experiments performed to compare the amounts of fission gases swept out of UNH solution with those amounts swept out of PU solution under idential condiditons. The charge wire technique was used. The essential date and the results are given in tables in the report.

Report published by the U.S. Bureau of Mines regarding accidents at mines located in the United States for all operations except coal mines. The report includes statistics about the number and kinds of accidents as well as information about the mining operations (i.e., number of persons employed, average amount of work performed per person, etc.).

None

Report discussing an investigation into the stalling characteristics, aileron effectiveness, and longitudinal stability of a scale model of the XB-36 airplane. The model was tested with the original configuration as well as with several modifications to the outboard panels and flap arrangement.

Report issued by the U.S. Bureau of Mines regarding specific manganese ore from Nevada and its use in electrolytic production. The development processes and methods are presented. This report includes tables, maps, illustrations, and photographs.

In this report a theory of thin airfoils of small camber is developed which permits either the velocity distribution corresponding to a given airfoil shape, or the airfoil shape corresponding to a given velocity distribution to be calculated. The procedures to be employed in these calculations are outlined and illustrated with suitable examples.

From Summary: "The results of an experimental investigation of several low-drag wing-nacelle combinations, incorporating internal air-flow systems, are presented. The external-drag increments due to these nacelles are between one-half and two-thirds of those of conventional nacelle forms. This improvement is accomplished with only minor effects on the lift and moment characteristics of the wing. The procedure employed to determine the external shape of such low-drag nacelles is considered in detail. The design of an efficient internal-flow system with or without a blower or throttle, presents no serious problems. The energy losses in the expansion before the engine and the contraction thereafter can be kept small. It is believed that these nacelles have a wide application in housing engine pusher-propeller units and, with some alteration, jet-propulsion devices. It is probable that the low external drags may not be realized if such nacelles are used with a tractor propeller because of the high level of turbulence in the propeller slipstream."

Report discussing testing of 2-percent additions of seven aromatic amines on the knock-limited performance of 28-R fuel in a CFR engine. The most effective antiknock additives are described.

"The knock-limited performance of blends of 0,50; and 100 percent by volume of 2,2,3-trimethylpentane in 28-R fuel determined with a modified F-4 engine at three sets of conditions varying from severe to mild at each of three compression ratios (6.0, 8.0, and 10.0). A comparison of the knock-limited performance of 2,2,3-trimethylpentane with that of triptane (2,2,3-trimethylbutane) is included. The knock-Limited performance of 2,2,3-trimethylpontane was usually more sensitive to either compression ratio or inlet-air temperature than 28-R fuel, but the ratio of the knock-limited indicated mean effective pressure of a given blend containing 2,2,3-trimethypentane and 28-R to the indicated mean effective pressure of 28-R alone was not greatly affected by compression ratio if the engine operating conditions were mild" (p. 1).

Report discussing the knock-limited performance of blends of 2,3-dimethylpentane and 23-R fuel in an F-4 engine at three sets of conditions and three compression ratios. The knock-limited performance of 2,3-dimethylpentane has about the same sensitivity to compression ratio and inlet-air temperature as 28-R fuel.

Report presenting a investigation covering the physical and chemical properties of various ethers as components of aviation fuels. Their antiknock effectiveness and methods of preparation and purification are included. Methyl tert-butyl ether gave the best knock-limited rich mixture response, but isopropyl tert-butyl ether and di-tert-butyl ether gave better results at lean mixtures.

Note presenting an investigation of the fatigue characteristics of riveted joints in aluminum alloy sheet. The purpose of this report is to summarize all the results of fatigue tests that have been made to date in the Aluminum Research Laboratories of lap joints with 1/8-inch aluminum alloy rivets.

Report outlining a study that tested the use of colorimetric methods with high concentration phosphoric acid as a solvent for rapid analysis of mixtures of T^+4 and T^+6.

A detailed description of the processing of pitchblende ores used at the Port Hope, Canada, refinery is given including both the recovery and purification of U and Fu. The health hazards present in the processing are discussed, and recommendations are made which will insure adequate health protection. (L.T.W.)

Note presenting a determination of the bonding strengths of two thermosetting adhesives, liquid Cycleweld C-3 and Ardux 1, to several aircraft materials using shear tests made on lap-joint specimens. The specimens were tested at 25 degrees Celsius and at subfreezing temperatures of approximately -40 degrees Celsius. Results regarding the specimens bonded under clamping pressure, specimens bonded after various surface treatments, specimens of metal bonded to plywood, and specimens of aluminum bonded to magnesium are provided.

Report presenting an investigation of various mechanical and physical properties of several expanded plastics and other low-density materials of interest for aircraft applications, such as heat insulation or the core of a sandwich material. The materials in the investigation included cellulose acetate plastic, polystyrene, a urea-formaldehyde resin, a zein product, hard rubber, balsa wood, and cellular glass.

Abstract. to estimate the oxygen picked up by thorium in casting a rapid method of running the acid insoluble content was developed. the quickest procedure consists of reacting with mixed acids, fuming with perchloric and filtration to separate the "free" thorium from the "combined". The precipitate is ignited and weighed as thorium dioxide.

Introduction. the conventional procedures of analysis for uranium and manganese can be employed in the analysis of alloys of these metals. The alloys are reacted with perchloric acid and hydrogen peroxide, fumed to remove any chloride ions, diluted to volume and aliquots analyzed by redoximetry.

Introduction. It has been known for a long time that thorium is precipitated by oxalic acid in acid solutions, but a survey of the literature showed no study of the limits of the acidity and oxalic acid excess which yield quantitative results. V. I. Spitzin reports on the solubility of thorium oxalate in varying concentrations of several acids, but the effect of an excess oxalic acid is not included. Since solutions are sometimes presented for analysis that contain more than the recommended two per cent mineral acid, it would be advantageous to be able to quantitatively remove the thorium without otherwise altering the solutions. This was especially of interest in solutions containing bismuth, since it was hoped that some amounts of thorium could be precipitated in nitric acid solutions containing large quantities of bismuth. In removing the bismuth, first by a bismuth oxychloride precipitation, thee is every opportunity for carrying of the thorium.

Report presenting direct-reading tables and charts for determining the drag or thrust coefficients from wake-survey measurements in the subsonic speed range. Additionally, numerical examples are provided using information from the tables.

From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number and to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."

From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."