Note presenting some of the basic general equations governing the three-dimensional compressible flow of gas through a compressor or a turbine in terms of velocity components, total enthalpy, and entropy. The equations are applied to investigate the maximum compatible number of the radial variations of the gas properties between successive blade rows that a designer is free to specify.

"Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given" (p. 1).

This semiannual report includes references in future items in the Brookhaven National Labratory program as well as an account of progress in the post six months.

None

Report presenting a landing investigation with a flying boat with a conventional configuration to determine the applicability of hydrodynamic impact theory in defining full-scale water impact loads. The results indicated that in addition to chine flare and angular rotation, there are many other factors that may affect overall load, such as elasticity effects, sustained pressures on the area behind the chine, and the effect of variation of wing lift during impact.

Report presenting comparisons of the structural efficiency of panels with straight-web and curved-web Y-section stiffeners. In the high-stress region in which failure is at least in part associated with local buckling, panels with curved-web Y-section stiffeners have higher structural efficiencies than panels with straight-web Y-section stiffeners, which is evidenced by higher average stresses at failure, smaller stiffener heights, or wider average spacing of rivet lines.

Report presenting an investigation of the exhaust of corrosive attack in an aluminum alloy wing employing an exhaust-gas-air mixture as a heating medium for ice prevention. There were no cases of structurally serious corrosion on either painted or plain specimens removed from the wing for detailed microscopic and metallurgic examination.

"Direct-reading design charts are presented for 24S-T aluminum-alloy flat compression panels having longitudinal formed Z-section stiffeners. These charts make possible the direct determination of the stress and all the panel proportions required to carry a given intensity of loading with a given skin thickness and effective length of panel" (p. 1).

"Direct-reading design charts are presented for 24S-T aluminum-alloy flat compression panels having longitudinal straight-web Y-section stiffeners. These charts make possible the direct determination of the stress and all the panel proportions required to carry a given intensity of loading with a given skin thickness and effective length of panel" (p. 1).

"A method developed in a previous report for finding the induced velocity field behind a supersonic wing with known load distribution is used to find the downwash behind a triangular wing with subsonic leading edges. Results are given for the chord plane in the extended vortex wake of the wing and for the vertical plane of symmetry up to about 20 percent of the wing span above the plane of the wing" (p. 1).

Report presenting an investigation of the take-off and landing behavior in waves of models of a hypothetical flying boat with hull length-beam ratios of 6 and 15. The flying boat had a design gross weight of 75,000 pounds, a wing loading of 41.1 pounds per square foot, and a power loading of 11.5 pounds per brake horsepower for take-off. Results regarding the landing behavior, spray characteristics, and taxiing and take-off behavior are provided.

Note presenting landing tests made with the PB2Y-6 flying boat to determine the effect of production step vents and forebody longitudinal steps on skipping. Skipping was found to occur at higher landing trims without either step vents or longitudinal steps. The steps were found to constitute a powerful method for improving the landing stability.

Note presenting calculations, based on linearized supersonic flow theory and on the additional assumption that the Mach cones yaw with the wing, to determine the effect of thickness on the lateral force and yawing moment of a sideslipping delta wing at supersonic speeds. Generalized equations are derived for delta wings with rhombic profile and constant thickness ratio.

Note presenting an investigation of a two-blade and a three-blade propeller on a slender-nose fighter airplane in climb and at high speed.

Report presenting tests in the gust tunnel of the 30 degree sweptback wing model to provide information on some of the problems encountered in the prediction of gust loads for airplanes incorporating swept wings. The results indicate that within the scope of the data and the values of gradient distance investigated, the maximum acceleration increment depends on the slope of the lift curve of an equivalent straight wing multiplied by the cosine of the angle of sweep and on the effect of gradual penetration of the sweptback wing into the gust.

Note presenting a prismatic-float forebody with an angle of dead rise of 40 degrees that was subjected to smooth-water impacts in the impact basin. The tests were made at fixed trims of 3, 6, 9, and 12 degrees for a range of flightpath angles from approximate 2 to 22 degrees. The data are presented and converted into dimensionless variables for correlation of the experimental results with hydrodynamic impact theory and for comparison of the runs among themselves.

Report presenting generalized radiation charts for the calculation of the irradiation from water vapor, carbon dioxide, ozone, and the earth in terms of appropriate parameters. Nocturnal irradiation was found to decrease greatly as a function of altitude and meteorological conditions.

Rotating-cylinder measurements of the icing conditions encountered in flight during the winter of 1947-48 are presented. Liquid water content, drop size, and temperature data are shown to be consistent with previously measured conditions and with proposed maximum icing conditions in supercooled layer-type clouds. Cumulative frequency graphs of meteorological parameters indicate the frequency with which various icing conditions have been encountered in the Great Lakes area and surrounding states.

Report issued by the Bureau of Mines regarding studies conducted on lead-zinc mines in Stevens County, Washington. As stated in the introduction, "this report presents the factual data obtained from the trenching and sampling operations" (p. 1). This report includes tables, maps, and illustrations.

Report presenting complete pressure-distributions measurements over a 24-inch-chord NACA 65,1-115 airfoil equipped with 20-percent-chord plain ailerons with aerodynamically smooth surfaces. Characteristics determined included airfoil normal-force, pitching-moment, aileron normal-force, and hinge-moment coefficients for a variety of Mach numbers, angles of attack, and aileron deflections. The aileron effectiveness parameter and section pitching-moment parameter are calculated.

Report issued by the Bureau of Mines regarding studies conducted on iron deposits located in Meagher County, Montana. As noted in the introduction, "details of geology, sampling, and beneficiation tests are presented in this report" (p. 1). This report includes tables, maps, and illustrations.

Report issued by the Bureau of Mines over studies conducted on the zinc-lead deposits in Cherokee County, Kansas. As stated in the introduction, "the purpose of this report is to present the factual data derived from both the preliminary examination and the subsequent field work." (p. 3). This report includes tables, and maps.

Monthly report of the U.S. Geological Survey's trace element investigations including an outline of field work, laboratory work, and staff activities that have been completed or are in process.

None