Report issued by the Bureau of Mines over investigations of mines in Stevens County, Washington. The history, geology, and physical features of the mines are presented. This report includes tables, maps, and illustrations.

Report issued by the Bureau of Mines over investigations on the McCormick chromite mine. Descriptions of the chromite deposits are presented. Details about the development made in the mine are listed. This report includes tables, maps, and illustrations.

Report issued by the Bureau of Mines over diamond-drilling projects in Salt Lake County. The geology, physical features, and history of the mines are presented. This report includes tables, maps, illustrations, and photographs.

Introduction: In order to determine the relative corrosion resistance of welded mild and stainless steels in Redox Stream IAW neutralized to pH 0, 2, and 10 a test program, described below, has been carried out.

The following report is based on the observations made during a visit to the Oak Ride National Laboratories of their Redox Pilot Plant equipment.

The following report describes polarographic methods that determine saturated aliphatic carbonyl compounds.

Summary: "This report investigates photographic methods of measuring beta radiation and includes a study of temperature effects on these measurements. Experimental data are submitted to show that an increase in film temperature before and during beta irradiation causes a definite increase in density for the same dosage. Recommendations drawn from experience gained in the experimental works are offered."

The following report discusses the presentation of preliminary density and viscosity data which may explain whether higher viscosities of the Deo Base-TBP systems, and a change in density differences between the two phases will lead to unsatisfactory column operation.

Technical report outlining the differences in conductivity of AGOT graphite and AGHT graphite.

"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 qualities. 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" (p. 1).

Note presenting pressure distribution measurements made on the wing of a fighter-type airplane to determine the span loading and to compare center-of-pressure results with those obtained by strain-gage measurements on the same airplane during a previous flight investigation. Flight tests were all made at a pressure altitude of about 30,000 feet and covered a Mach number range from approximately 0.35 to 0.81. Results regarding additional air load, spanwise center of pressure of additional air load, basic air load distribution, and span loading during a stall and buffeting are provided.

From Summary: "Included in the report are the results of total-pressure surveys made at downstream ends of the mixing tubes."

"The experimental results are presented for the second part of an investigation of the compressive strength of 75S-T6 aluminum-alloy flat panels with longitudinal extruded Z-section stiffeners. This part of the investigation is particularly concerned with panels in which the ratio of the thickness of the stiffener material to the skin material is small and the ratio of stiffener spacing to skin thickness is large" (p. 1).

Note presenting an investigation with the aim of achieving improved hydrodynamic qualities for flying boats, which involved determining the combined effect of a warped forebody and extended afterbody on the hydrodynamic characteristics of a full having a basic length-beam ratio of 15. Results regarding longitudinal stability, landing stability, spray characteristics, and landings in waves are provided.

Report presenting testing to determine the force developed in a shock strut as a function of the flexibility of the attached wing structure. Both the experiment and analysis indicated that wing flexibility had some effect on the shape and peak value of the force-time curve in a shock strut.

"Available information on gust structure, airplane reactions, and pertinent operating statistics has been examined. This paper attempts to coordinate this information with reference to the prediction of gust loads on airplanes. The material covered represents research up to October 1947" (p. 1).

Report presenting flight-test measurements and corresponding pilot's opinions of the forward-flight longitudinal flying qualities characteristics of several single-rotor helicopters. The most important consideration for satisfactory characteristics appears to be the prevention of prolonged stick-fixed divergent tendencies. Results regarding the characteristics appreciated, theoretical analysis of pull-up characteristics, and practical requirements are provided.

Report presenting the results of an experimental investigation to determine the downwash in the region of the trailing vortex behind a trapezoidal-wing tip in a supersonic stream. Results regarding the downwash at spanwise stations, downwash at chordwise stations, and wake survey are provided.

Report presenting an investigation to determine the effects of number of wings on the aileron rolling effectiveness of an RM-5 test vehicle using the free-rolling wind-tunnel testing technique through a speed range to Mach number 0.9. The wings tested had neither taper nor sweepback and were equipped with full-span 20-percent-chord sealed and faired ailerons. Results indicated that increasing the number of wings resulted in a decrease in rolling effectiveness so that results obtained from the test of the three-wing model were closer to conventional-airplane-configuration results than the four-wing data.

"A spin-tunnel investigation has been made to determine the probability of external fuel tanks striking an airplane after being jettisoned in a spin. The investigation showed that for straight-wing fighter-type designs in any case in which jettisoning of tanks in a spin might aid spin recovery the tanks would probably clear all parts of the airplane" (p. 1).

From Introduction: "Water injection at the compressor inlet has been successfully used to increase the thrust of turbojet engines. References 1 and 2 indicate that the sea-level static thrust of a centrifugal-flow-type turbojet engine may be increased about 25 percent by use of liquid injection. Reference 3 indicates that greater thrust augmentation is possible at a compressor pressure ratio of 11 than of 4."

Report presenting the ditching characteristics of the Douglas DC-4 and DC-6 in a water tank. Dynamically similar models of 1/16 scale were used for the investigation, which was conducted in calm and rough water. The ditching characteristics and safest ditching procedures were determined by testing at various landing attitudes, speeds, and simulated conditions of damage.

Report presenting a preliminary theoretical and experimental investigation of the supersonic characteristics of blunt-trailing-edge airfoils. Results regarding the drag measurements at zero lift, measurements at angle of attack, and a general discussion of the theoretical and experimental results is provided.

Report presenting an investigation of pressure distributions and flow characteristics at low speed through a range of yaw and angle of attack through the stall for three small-scale low-aspect-ratio pointed wings with varying degrees of trailing-edge sweep. An effort was made to correlate pressure distributions with the strong conical vortex flow observed. Results regarding chordwise pressure distributions and flow characteristics, section lift characteristics at zero yaw, spanwise-load distributions, centers of pressure at zero yaw, and wing force and moment characteristics are provided.