Text describing climate, agriculture, and soils of Brown County, Texas.

Map displays soil types along with bayous, lakes, rivers, agricultural field stations, refineries, pipelines, power transmission lines, towns, churches, country clubs, roads, and railroads. Includes legend and symbols. Separate, supplemental chart shows principle characteristics of each soil type.

"About 500 additional references pertaining to hydrodynamic design of seaplanes have been compiled, and the information is presented in the form of abstracts classified under six main headings:GENERAL INFORMATION, HYDROSTATICS, HYDRODYNAMICS, AERODYNAMICS, OPERATION, and RESEARCH. The compilation is an extension of NACA RM No. L6I13, entitled "Abstracts Pertaining to Seaplanes," by Jerold M. Bidwell and Douglas A. King. An author index and a subject index are included" (p. 1).

Note presenting an application of the method of superposition of linearized conical flows to the calculatin of the aerodynamic properties of thin, flat, swept-back wings at an angle of attack. Various cases are distinguished, depending on the sweep of the leading and trailing edges relative to their respective Mach lines. The results of the calculations emphasize the indications of the theory that the determining factor in the aerodynamic performance of wings is the disposition of area relative to the Mach lines.

Report presenting testing of three different types of afterbodies on a powerful dynamic model of a flying boat with a basic length-beam ratio of 10.0. The three afterbodies tested were one with constant dead rise, one with warped dead rise, and one of extended length with warped dead rise. Results regarding aerodynamic characteristics and hydrodynamic characteristics are provided.

Report presenting results for a test program on 24S-T aluminum-alloy flat compression panels with longitudinal hat-section stiffeners. The results for panels in which the thicknesses of the stiffener material are 0.39 and 1.25 times the skin thickness are presented and incorporated with previously provided results. These results are presented in tabular and graphical form and show the effect of the relative dimensions of a panel on the buckling stress and the average stress at failure.

Report presenting the use of known conical-flow solutions of the linearized equation for the velocity potential in supersonic flow as applied to the calculation of the characteristics of control surfaces. Solutions for the pressure distributions are obtained for control surfaces with hinge lines swept ahead or behind the Mach line when the control-surface trialing edge is swept ahead of the Mach line.

Report presenting an investigation of a method for the dynamic calibration of aneroid altimeters under conditions of rapidly changing pressures simulating pressure conditions in climbs and dives. Three experimental tests were carried out in order to explore the accuracy and determination of certain variables for optimum functioning.

Note presenting data on the tensile strength, fatigue strength, creep properties, and thermal expansion of forged aluminum alloys XB18S, 18S, 24S, and 32S, which are pertinent to the application of these alloys in the temperature range from 70 to 800 degrees Fahrenheit. The paper also includes a critical discussion of the data and its application to design of aircraft engines.

Report presenting an evaluation to approximate engine-jacket conditions in a laboratory setting in order to determine their cooling properties using water and methanol. Results regarding the heat balance, tube-wall temperature distribution, nonboiling data, local boiling without air, entrained air without local boiling, entrained air with local boiling, and application to engine cooling are provided.

Note presenting a theoretical analysis of an initially flat, rectangular plate with large deflections under either normal pressure or combined normal pressure and side thrust.

Note presenting wind-tunnel tests to determine the aerodynamic section characteristics of an NACA 0009 airfoil with plain flaps 25 and 50 percent of the airfoil chord. The flaps were tested independently and in combination. The results indicated that the larger flap would provide greater lift increments but would lose lift effectiveness at the higher deflections and at a lower angle of attack than would the smaller flap.

A solution is presented for the problem of the buckling of a column on equally spaced deflectional and rotational springs. Useful charts, which relate deflectional spring stiffness, rotational spring stiffness, and buckling load, are given for columns having two, three, four, and infinite number of spans.

Note presenting an investigation of the PV-2 helicopter rotor to determine the basic performance characteristics of a fully articulated rotor. Results are presented of the blade-motion observations at the 0.75-radius station for a limited range of flight conditions. Both the measured results and a comparison with theoretical results are provided.

Note presenting equations derived for the wave drag of sweptback untapered wings at zero lift with thin double-wedge sections and arbitrary chordwise location of maximum thickness. Calculations are presented for a representative supersonic plan form. Results regarding section wave drag, wing wave drag, comparison with two-dimensional theory, and comparison with tapered wings are provided.

Note presenting an untapered aluminum-alloy box beam, representing the main structural component of a full-span, two-spar, 45 degree swept wing with a carry-through bay, was subjected to tip bending and twisting loads and its stresses and distortions were measured. The investigation revealed that for bending, the important effect of sweep was to cause a considerable build-up of normal stress and vertical shear stress in the rear spar near the fuselage.

Report presenting a strain-energy theory for the calculation of the buckling load in general instability of circular reinforced monocoque cylinders with a side cutout and subjected to pure bending.

Report presenting solutions obtained for the damping in roll of triangular, trapezoidal, rectangular, and two swept-back plan forms. The results indicate that as the aspect ratio is increased, the limiting value of the damping in roll for trapezoidal and rectangular plan forms is equal to the value for two-dimensional flow which is twice the limiting value for triangular plan forms.

Note presenting expressions for the aerodynamic coefficients of thin pointed wings with three types of trailing edge. The derivation is based on an equation previously derived for the pressure distribution on a thin yawed delta wing at supersonic speeds.

Note presenting mathematical expressions derived for the stress distribution in a wood beam of rectangular cross section subjected to a concentrated load. The stress distributions were expressed in terms of infinite series. A method of reducing the infinite series to the sum of a finite series and a closed form was described.

Report presenting the use of a rapid compression machine to determine the variation in ignition delay and rate of pressure rise after compression for four fuels: isooctane, 100-octane gasoline, triptane, and benzene. The only independent variables were fuel-air ratio and compression ratio. Results regarding the fuel-air-ratio runs, compression-ratio runs, and a comparison of all of the fuels are provided.

"Theoretical and experimental investigations were made of the distribution of strains in a plywood sheet-stringer combination used as the chord member of a box beam acted upon by bending loads. The theoretical solution was obtained with the help of the principle of minimum potential energy and certain simplifying assumptions. Strain measurements were made on a build-up box beam by means of electrical-resistance strain gages connected with strain indicators" (p. 1).

Report presenting initial flight tests of two simplified flutter vehicles. Test results were in agreement with the results of the freely-falling-body test in that the wing failures in the transonic range occurred at velocities greater than the flutter velocity calculated from the two-dimensional theory.

Report presenting an investigation to obtain the pressure distribution over a sharp-nose body of revolution with a circular-arc profile and fineness ratio 6 at transonic speeds using the NACA wing-flow method. Results regarding the variation of pressure coefficient with Mach number, pressure distributions along the body axis, pressure drag, and effects of interference and horizontal gradient are provided.