Report presenting wind tunnel tests of NACA 65(216)-420 and 66(218)-420 airfoils at speeds up to and slightly above the critical. Section coefficients of lift, drag, and pitching-moment and extensive pressure-distribution data are presented. The critical speed for these airfoils at their design life coefficient of 0.4 is shown to be about 460 miles per hour at seal level and about 415 miles per hour at 25,000 feet altitude.

Report presenting tests to investigate the effect of 2-percent additions of 11 aromatic amines on the knock-limited performance of AN-F-28 fuel. A total of 48 aromatic amines are being prepared for knock tests. Results regarding the knock-limited performance data, antiknock effectiveness, and knock-limited powers are provided.

"Following a brief history of the NACA investigation of jet-propulsion, a discussion is given of the general investigation and analyses leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight-performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made" (p. 1).

From Summary: "Guide fixtures are described by means of which axial fatigue loads including compression may be applied to a thin sheet-metal specimen. Tests indicate that the guides prevented buckling without bypassing the load or injuring the specimen."

Report discusses the results of strength tests of several curved-sheet 24S-T aluminum alloy specimens stiffened longitudinally and transversely and loaded in shear. Curved-web beams and cylindrical shells were both examined in the tests. Results provided include the load at which the sheet began to show shear buckles, where the buckles occurred, and whether or not the failures involved rupture of the sheet.

Report presenting flight measurements of the pressures on the horizontal tail surfaces of a typical propeller-driven pursuit airplane during stalled pull-outs at high Mach number. Unit loads measured on the stabilizer at safe maneuvering limits were not only considerably in excess of the design unit loads, but also occurred in a direction opposite to the design loads. Revision of the tail-load design requirements and manner of specifying safe maneuverability limits to pilots appears necessary.

Report presenting testing of several designs of nitrided-steel piston rings under variable conditions of output. Testing indicated the importance of good surface finish and conformity of the ring to the bore. Results regarding temperature tests, single-cylinder-engine tests, and multicylinder-engine tests are provided.

"Several designs of nitrided-steel piston rings were performance-tested under variable conditions of output. The necessity of good surface finish and conformity of the ring to the bore was indicated in the preliminary tests. Nitrided-steel rings of the same dimensions as cast-iron rings operating on the original piston were unsatisfactory, and the final design was a lighter, rectangular, thin-face-width ring used on a piston having a maximum cross-head area and a revised skirt shape. Results were obtained from single-cylinder and multicylinder engine runs" (p. 1).

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This paper presents the history and current status Of computer networking between IHEP in Beijing, China and the rest of the world, starting with no links at the beginning of 1987 thru X.25 public networks and dial up links, to the installing, in March 1993, of one of the first dedicated 64 kbps satellite computer links between China and the outside world. In May 1994, IHEP became the first Chinese institution to have a fully operational world-wide Internet connection. Experience with this dedicated link between SLAC and IHEP will be presented together with future plans to add a land line between KEK and IHEP and to extend the links within China.

The resonance absorption of a lump is described in terms of three components. Calculations of resonance absorption are carried out using the model for the resonance spectrum of uranium recently derived; calculations are also made with variations of this model which involve local fluctuations in level strengths. For metal and oxide lumps the agreement with observation is satisfactory. For dilute mixtures, whose resonance activation was measured by Mitchell, computed values fall 20% to 30% above measured ones.

"F-3 and F-4 knock data are presented for blends of 0, 20, 40, 60, and 80 percent by volume of triptane in 28-R reference fuel plus approximately 4.6 ml TEL per gallon in the final blends. For comparison of knock-limited performance, 28-R reference fuel containing 2.7 percent by volume of xylidines and leaded to 6 ml TEL per gallon is included. In order to provide information on temperature sensitivities, two sets of modified conditions were used in addition to the standard F-4 engine conditions" (p. 1).

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The transition region between two parts of a pile which have different compositions is investigated. In the case where the moderator is the same in both parts of the pile, it is found that the diffusion constant times thermal neutron density plus diffusion constant times fast neutron density satisfied the use pile equations everywhere, right to the boundary. More complicated formulae apply in a more general case.

"This report outlines the flight conditions that are usually critical in determining the design of components of an airplane which affect its stability and control characteristics. The wind-tunnel tests necessary to determine the pertinent data for these conditions are indicated, and the methods of computation used to translate these data into characteristics which define the flying qualities of the airplane are illustrated" (p. 1).

Report issued by the U.S. Bureau of Mines discussing fatalities of mine workers while wearing self-contained oxygen breathing apparatuses. Descriptions of the circumstances surrounding the deaths of 26 workers are presented. This report includes a table.

Report issued by the U.S. Bureau of Mines discussing the development and construction of ventilation doors in mine operations. The importance of functioning ventilating doors is presented. The construction process is described in detail. This report includes an illustration.

Report discusses pressure-distribution tests of a plain flap with interchangeable beveled trailing edges on an NACA 0009 airfoil. The flap chord was 30 percent of the airfoil chord and the bevel chords were 15 and 20 percent of the flap chord. The purpose of these tests was to supply pressure-distribution data that may be used for structural and aerodynamic design of horizontal and vertical tail surfaces.

Report presenting a wind tunnel investigation of a beveled aileron shape designed to increase the useful deflection range. The purpose of the investigation was to determine the general aerodynamic characteristics of this aileron and, in particular, to determine its useful angular range. Results regarding the effect of the hinge-gap seal, the surface condition and Reynolds number, and effect of aileron profile are provided.

Report presenting testing of a model of the Northrop XB-35 airplane in the free-spinning tunnel in order to determine the spin characteristics and tumbling tendencies of the airplane. The spin tests indicated that for the normal loading condition, the model would not spin in the direction of the rudder for either the clean or the landing condition unless the wheel was set over with the rudder. Results regarding the spin tests in the clean condition, spin tests in the landing condition, tumbling tests, and consideration of control forces are provided.

Report presenting preliminary tests in tank no. 1 to investigate the hydrodynamic qualities of a streamline body of revolution of a fineness ratio of 5.14 with and without a lifting hydrofoil. Results regarding interference, incidence, spray, trimming moment, comparison with a conventional float, and aerodynamic drag are provided.

Report discusses the results of testing of 10-inch 24S-T aluminum alloy shear panels with 1.5 inch holes with notched edges to determine if a notch decreases the strength of the panel and if reinforcements can overcome the negative effects of the notch. The notch did appear to increase the stress concentration around the holes, but the lack of applicability to real-world scenarios is discussed.

From abstract: "Comparison of the activity produced by fast neutrons on lead with other activations corroborates the assignment of the 3.2 hr. activity as Pb209, and the assignment of the reaction as capture of fast neutrons. Two different measurements show that the neutrons captured have energies greater than 100 KEV. This average capture cross section for primary neutrons from 7.5 MEV deuterons on a thick target of beryllium is measured as 10[^]-27 ca[^]2."

Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 0009 airfoil with flaps having chord at 3 locations of the airfoil chord and three degrees of the beveled trailing edges. The results indicated that, with a smooth leading edge, the increased trailing-edge angle on the flaps with sealed gaps decreased the slope of the control-fixed lift curve and the lift effectiveness.