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Manufacture of Paraffin Wax from Petroleum

Description: From Introduction: "The primary purpose of this bulletin is to describe the metallurgical treatment and properties of the alloys as developed in research at the laboratories of the Bureau of Mines at Rolla, Mo., and to present a substantial amount of unpublished data."
Date: 1935
Creator: Espach, Ralph H.
Partner: UNT Libraries Government Documents Department

Engineering Factors in the Ventilation of Metal Mines

Description: From Introduction Purpose and Scope of Report: "In the belief that the quickest and cheapest method of obtaining effective ventilation of metal mines with regard to air conditions that promote efficiency, health, and safety is through more general application of the engineering factors involved rather than by trial and error and this method of attacking ventilation problems will be facilitated by a simple, concise statement of these factors and the methods of using them, an attempt is made in this bulletin to present the subject of metal-mine ventilation to mine operators in a practical way."
Date: 1935
Creator: McElroy, G. E.
Partner: UNT Libraries Government Documents Department

Geology of the Santa Rita Mining Area, New Mexico

Description: From abstract: The Santa Rita mining area (pl. 1), covering 35 square miles of semiarid mountainous land, lies within the Silver City 30-minute quadrangle, Grant County, N. Mex., and includes the most productive part of the Central or Hanover mining district. Ore was produced in this district as early as 1804 and production continued intermittently for a century before the developments were undertaken that led to large-scale copper mining, which began in 1912. The output of zinc, lead, and iron increased markedly about the same time.
Date: 1935
Creator: Spencer, Arthur C. & Paige, Sidney
Partner: UNT Libraries Government Documents Department

The Contact Mining District, Nevada

Description: From abstract: This report summarizes the results of a reexamination, in 1930, of the Contact mining district, in Elko County, northern Nevada. A report published as a result of a visit in 1910 summarizes the major features of the geology of the district, and the principal new data in the present paper pertain to mining development occasioned by the completion of a railroad through the camp in 1925.
Date: 1935
Creator: Schrader, Frank C.
Partner: UNT Libraries Government Documents Department

The 1934 contest for the Deutsch de la Meurthe trophy

Description: This report presents a description of the rules, history and new technical innovations in the Deutsch de la Meurthe Cup race of 1934.
Date: February 1935
Creator: Leglise, Pierre
Partner: UNT Libraries Government Documents Department

Calculations of the effect of wing twist on the air forces acting on a monoplane wing

Description: A method is presented for calculating the aerodynamic forces on a moncylane wing, taking into account the elastic twisting of the wing due to these forces. The lift distribution along the span is calculated by the formulas of Amstutz as a function of the geometrical characteristics of the wing and of the twist at stations 60 and 90 percent of the semispan. The twist for a given lift distribution is calculated by means of influence lines. As a numerical example, the forces on a Swiss military D.2V airplane are calculated. Comparisons with the strip method and with the ordinary stress-analysis method are also given.
Date: January 1, 1935
Creator: Datwyler, G
Partner: UNT Libraries Government Documents Department

Flight tests of a balanced split flap with particular reference to rapid operation

Description: The flight path of a small parasol monoplane equipped with a special type of balanced split flap was determined for a series of glides during which the time taken to deflect or retract the flap was varied from 1 to 15 seconds in order to study the effect of the time taken to complete a flap movement on the motion of an airplane between the start of a flap movement and the attainment of steady flight with the new flap setting. For flap movements accompanied by a change of lift characteristics, and consequently of velocity, there is an appreciable delay in obtaining a desired change in glide angle even though the flap is operated instantaneously. Immediate control of the glide path is obtained only when the speed is maintained during the flap movement. When the speed is changed, the deviation from the desired path during the transition increases in proportion to the rapidity with which the flap is moved so that, with a high-lift flap, abrupt retraction at speeds less than the minimum speed with the flap retracted may be dangerous if practiced close to the ground.
Date: December 1, 1935
Creator: Soule, H A
Partner: UNT Libraries Government Documents Department

A general tank test of NACA model 11-C flying-boat hull, including the effect of changing the plan form of the step

Description: The results of a general tank test model 11-C, a conventional pointed afterbody type of flying-boat hull, are given in tables and curves. These results are compared with the results of tests on model 11-A, from which model 11-C was derived, and it is found that the resistance of model 11-C is somewhat greater. The effect of changing the plan form of the step on model 11-C is shown from the results of tests made with three swallow-tail and three pointed steps formed by altering the original step of the model. These results show only minor differences from the results obtained with the original model.
Date: August 1, 1935
Creator: Dawson, John R
Partner: UNT Libraries Government Documents Department

The Effect of the Angle of Afterbody Keel on the Water Performance of a Flying-Boat Hull Model

Description: NACA model 11-C was tested according to the general method with the angle of afterbody keel set at five different angles from 2-1/2 degrees to 9 degrees, but without changing other features of the hull. The results of the tests are expressed in curves of test data and of non-dimensional coefficients. At the depth of step used in the tests, 3.3 percent beam, the smaller angles of afterbody keel give greater load-resistance ratios at the hump speed and smaller at high speed than the larger angles of afterbody keel. Comparisons are made of the load-resistance ratios at several other points in the speed range. The effect of variation of the angle of afterbody keel upon the take-off performance of a hypothetical flying boat of 15,000 pounds gross weight having a hull of model 11-C lines is calculated, and the calculations show that the craft with the largest of the angles of afterbody keel tested, 9 degrees, takes off in the least time and distance.
Date: September 1, 1935
Creator: Allison, John M.
Partner: UNT Libraries Government Documents Department

Bending stresses due to torsion in cantilever box beams

Description: The paper beings with a brief discussion on the origin of the bending stresses in cantilever box beams under torsion. A critical survey of existing theory is followed by a summary of design formulas; this summary is based on the most complete solution published but omits all refinements considered unnecessary at the present state of development. Strain-gage tests made by NACA to obtained some experimental verification of the formulas are described next. Finally, the formulas are applied to a series of box beams previously static-tested by the U.S. Army Air Corps; the results show that the bending stresses due to torsion are responsible to a large extent for the free-edge type of failure frequently experienced in these tests.
Date: June 1, 1935
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department

Tank tests of a model of a flying-boat hull having a longitudinally concave planing bottom

Description: The NACA model 11-B, which has a longitudinally concave planing bottom forward of the step, was tested over a wide range of loading. The results of the tests are presented as curves of resistance and trimming moment plotted against speed for various trim angles and as curves of resistance coefficient at best trim angle, and trimming-moment coefficient. The characteristics of the form at the optimum trim are compared with those of NACA model 11-C which has the same form with the exception of a planing bottom longitudinally straight near the step. Photographs of the models being towed in the tank are included for a comparison of the spray patterns. At the best angles of trim in each case model 11-B has lower resistance at high speeds, a higher maximum positive trimming moment near the hump speed, and a more favorable spray pattern than of model 11-C.
Date: November 1, 1935
Creator: Parkinson, J B
Partner: UNT Libraries Government Documents Department

Tank tests of a model of a flying-boat hull with a fluted bottom

Description: A 1/5-scale model of a flying-boat hull having flutes in the bottom both forward and aft of the step (NACA model 19) was tested to determine its water performance. The model was also tested after the successive removal of the flutes on the afterbody and forebody. The results from these tests are compared with those from tests of a model of the hull of the Navy PN-8 flying boat and it is concluded that the fluted-bottom model and its modifications are inferior to the model of the PN-8.
Date: March 1, 1935
Creator: Dawson, John R
Partner: UNT Libraries Government Documents Department

Vortex noise from rotating cylindrical rods

Description: A series of round rods of the some diameter were rotated individually about the mid-point of each rod. Vortices are shed from the rods when in motion, giving rise to the emission of sound. With the rotating system placed in the open air, the distribution of sound in space, the acoustical power output, and the spectral distribution have been studied. The frequency of emission of vortices from any point on the rod is given by the formula von Karman. From the spectrum estimates are made of the distribution of acoustical power along the rod, the amount of air concerned in sound production, the "equivalent size" of the vortices, and the acoustical energy content for each vortex.
Date: February 1, 1935
Creator: Stowell, E Z & Deming, A F
Partner: UNT Libraries Government Documents Department

Strength tests of thin-walled duralumin cylinders in combined transverse shear and bending

Description: This report is the fourth of a series presenting the results of strength tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results on 100 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that as the ratio of moment to shear varies from small to large values the failure changes from a shear to a bending type. In the report a chart is presented that shows the corresponding changes in strength.
Date: April 1, 1935
Creator: Lundquiest, Eugene E.
Partner: UNT Libraries Government Documents Department

Strength tests of thin-walled duralumin cylinders of elliptic section

Description: This report is the fifth of a series presenting the results of strength tests of thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results obtained from torsion tests on 30 cylinders, pure bending tests on 30 cylinders, and combined transverse shear and bending tests on 60 cylinders. All the cylinders tested were elliptic section with the ends clamped to rigid bulkheads. In the pure bending and combined transverse shear and bending tests the loads were applied in the plane of the major axis. The results of the tests on elliptic cylinders are correlated with the results of corresponding tests on circular cylinders and are presented in charts suitable for use in design.
Date: May 1, 1935
Creator: Lundquist, Eugene E. & Burke, Walter F.
Partner: UNT Libraries Government Documents Department

The compressibility bubble

Description: Simultaneous air-flow photographs and pressure-distribution measurements have been made of the NACA 4412 airfoil at high speeds in order to determine the physical nature of the compressibility bubble. The flow photographs were obtained by the Schlieren method and the pressures were simultaneously measured for 54 stations on the 5-inch-chord wing by means of a multiple-tube photographic manometer. Pressure-measurement results and typical Schlieren photographs are presented. The general nature of the phenomenon called the "compressibility bubble" is shown by these experiments. The source of the increased drag is the compression shock that occurs, the excess drag being due to the conversion of a considerable amount of the air-stream kinetic energy into heat at the compression shock.
Date: October 1, 1935
Creator: Stack, John
Partner: UNT Libraries Government Documents Department

Full-scale force and pressure-distribution tests on a tapered U.S.A. 45 airfoil

Description: This report presents the results of force and pressure-distribution tests on a 2:1 tapered USA 45 airfoil as determined in the full-scale wind tunnel. The airfoil has a constant-chord center section and rounded tips and is tapered in thickness from 18 percent at the root to 9 percent at the tip. Force tests were made throughout a Reynolds Number range of approximately 2,000,000 to 8,000,000 providing data on the scale effect in addition to the conventional characteristics. Pressure-distribution data were obtained from tests at a Reynolds Number of approximately 4,000,000. The aerodynamic characteristics given by the usual dimensionless coefficients are presented graphically.
Date: March 1, 1935
Creator: Parsons, John F
Partner: UNT Libraries Government Documents Department

Performance tests of a single-cylinder compression-ignition engine with a displacer piston

Description: Engine performance was investigated using a rectangular displacer on the piston crown to cause a forced air flow in a vertical-disk combustion chamber of a single-cylinder, 4-stroke-cycle compression-ignition engine. The optimum air-flow area was determined first with the area concentrated at one end of the displacer and then with the area equally divided between two passages, one at each end of the displacer. Best performance was obtained with the two-passage air flow arranged to give a calculated maximum air-flow speed of 8 times the linear crank-pin speed. With the same fuel-spray formation as used without the air flow, the maximum clear exhaust brake mean effective pressure at 1,500 r.p.m. was increased from 90 to 115 pounds per square inch and the corresponding fuel consumption reduced from 0.46 to 0.43 pound per brake horsepower-hour. At 1,200 r.p.m., a maximum clear exhaust brake mean effective pressure of 120 pounds per square inch was obtained at a fuel consumption of 0.42 pound per brake horsepower-hour. At higher specific fuel consumption the brake mean effective pressure was still increasing rapidly.
Date: February 1, 1935
Creator: Moore, C S & Foster, H H
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests of a cyclogiro rotor

Description: During an extensive study of all types of rotating wings, the NACA examined the cyclogiro rotor and made an aerodynamic analysis of that system (reference 1). The examination disclosed that such a machine had sufficient promise to justify an experimental investigation; a model with a diameter and span of 8 feet was therefore constructed and tested in the 20-foot wind tunnel during 1934. The experimental work included tests of the effect of the motion upon the rotor forces during the static-lift and forward-flight conditions at several rotor speeds and the determination of the relations between the forces generated by the rotor and the power required by it.
Date: May 1, 1935
Creator: Wheatley, John B & Windler, Ray
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests of a wing with a trailing-edge auxiliary airfoil used as a flap

Description: This report gives the characteristics of a wing with an auxiliary airfoil mounted near its trailing edge and used as a flap. The tests were made with a 10 by 60 inch Clark Y main airfoil and an NACA 0012 flap having a chord equal to 15 percent of the main wing chord. The axis of the flap in all cases was on the flap chord and 20 percent back from its leading edge. The optimum location of the flap axis relative to the main wing for maximum lift was found to be 1.25 percent of the main wing chord behind the trailing edge and 2.5 percent below the chord. In this position C(sub L max) was increased from 1.250 (for the plain wing) to 1.810 at 45 degrees deflection of the flap and C(sub D min) was decreased form 0.0155 to 0.0146 at minus 5 degrees deflection, the coefficient in each case being based on the sum of the flap and wing areas. No serious adverse change in lateral stability was found to result from the use of the flap in the optimum position.
Date: January 1, 1935
Creator: Noyes, Richard W
Partner: UNT Libraries Government Documents Department

The effect of depth of step on the water performance of a flying-boat hull model

Description: NACA model 11-C was tested with four different depths of step to obtain information as to the effect of the depth of step on the water performance. The depths of step were selected to cover the practicable range of depths and in each case the included angle between the forebody and afterbody keels was kept the same 6-1/2 degrees. Small depths of step were found to give lower resistance at speeds below and at the hump speed of the model and greater depths of step lower resistance at high speeds. For low resistance throughout the speed range of the model investigated the most desirable depth of step is from 2.5 to 4.0 percent of the beam. The change of the best trim angle caused by variation of the depth of step was not appreciable. Increased depth of step caused increases in the maximum positive trimming moments at all trim angles investigated.
Date: July 1, 1935
Creator: Bell, Joe W
Partner: UNT Libraries Government Documents Department

The initial torsional stiffness of shells with interior webs

Description: A method of calculating the stresses and torsional stiffness of thin shells with interior webs is summarized. Comparisons between experimental and calculated results are given for 3 duralumin beams, 5 stainless steel beams and 2 duralumin wings. It is concluded that if the theoretical stiffness is multiplied by a correction factor of 0.9, experimental values may be expected to check calculated values within about 10 percent.
Date: September 1, 1935
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department

The 6-foot-4-inch wind tunnel at the Washington Navy Yard

Description: Report discussing the 6-foot-4-inch wind tunnel and its auxiliary equipment has proven itself capable of continuous and reliable output of data. The real value of the tunnel will increase as experience is gained in checking the observed tunnel performance against full-scale performance. Such has been the case of the 8- by 8-foot tunnel, and for that reason the comparison in the calibration tests have been presented.
Date: August 1935
Creator: Desmond, G L & Mccrary, J A
Partner: UNT Libraries Government Documents Department