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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Year: 1942
 Collection: Technical Report Archive and Image Library
Adjustment of stick force by a nonlinear aileron-stick linkage
No Description digital.library.unt.edu/ark:/67531/metadc61609/
Aerodynamic characteristics and flap loads of the brake-flap installation on the 0.40-scale model of the F4F-3 left wing panel
No Description digital.library.unt.edu/ark:/67531/metadc61360/
Aerodynamic characteristics for internal-balance and Frise type ailerons on an NACA 6 series low-drag tip section of the wing for the XP-63 airplane
No Description digital.library.unt.edu/ark:/67531/metadc61354/
Aerodynamic Heat-Power Engine Operating on a Closed Cycle
Hot-air engines with dynamic compressors and turbines offer new prospects of success through utilization of units of high efficiencies and through the employment of modern materials of great strength at high temperature. Particular consideration is given to an aerodynamic prime mover operating on a closed circuit and heated externally. Increase of the pressure level of the circulating air permits a great increase of limit load of the unit. This also affords a possibility of regulation for which the internal efficiency of the unit changes but slightly. The effect of pressure and temperature losses is investigated. A general discussion is given of the experimental installation operating at the Escher Wyss plant in Zurich for a considerable time at high temperatures. digital.library.unt.edu/ark:/67531/metadc63985/
Aerodynamic problems in the design of efficient propellers
No Description digital.library.unt.edu/ark:/67531/metadc62127/
Aerodynamic tests of an M-31 bomb in the 8-foot high-speed tunnel
No Description digital.library.unt.edu/ark:/67531/metadc62440/
The aerodynamic tests of three Edo floats for the SB2U-3, 0S2U-2, and XSB2C-2 seaplanes - NACA models 106-K, 107-K, and 125-AH
No Description digital.library.unt.edu/ark:/67531/metadc61712/
Aerodynamics of the Fuselage
The present report deals with a number of problems, particularly with the interaction of the fuselage with the wing and tail, on the basis of simple calculating method's derived from greatly idealized concepts. For the fuselage alone it affords, in variance with potential theory, a certain frictional lift in yawed flow, which, similar to the lift of a wing of small aspect ratio, is no longer linearly related to the angle of attack. Nevertheless there exists for this frictional lift something like a neutral stability point the position of which on oblong fuselages appears to be associated with the lift increase of the fuselage in proximity to the zero lift, according to the present experiments. The Pitching moments of the fuselage can be determined with comparatively great reliability so far as the flow conditions in the neighborhood of the axis of the fuselage can be approximated if the fuselage were absent, which, in general, is not very difficult. For the unstable contribution of the fuselage to the static longitudinal stability of the airplane it affords comparatively simple formulas, the evaluation of which offers little difficulty. On the engine nacelles there is, in addition a very substantial wing moment contribution induced by the nonuniform distribution of the transverse displacement flow of the nacelle along the wing chord; this also can be represented by a simple formula. A check on a large number of dissimilar aircraft types regarding the unstable fuselage and nacelle moments disclosed an agreement with the wind-tunnel tests, which should be sufficient for practical requirements. The errors remained throughout within the scope of instrumental accuracy. digital.library.unt.edu/ark:/67531/metadc63732/
Analyses of West Virginia Coals
Technical paper issued by the Bureau of Mines over studies of West Virginia coal fields. Characteristics of coals and mines are discussed. This paper includes tables, maps, and illustrations. digital.library.unt.edu/ark:/67531/metadc66447/
Analysis of heat and compressibility effects in internal flow systems and high-speed tests of a ram-jet system
No Description digital.library.unt.edu/ark:/67531/metadc279610/
An analysis of the effect of core structure and performance on volume and shape of cross-flow tubular intercoolers
No Description digital.library.unt.edu/ark:/67531/metadc62073/
Analytical theory of the Campini propulsion system
Following the description of the new propulsion system and the definition of the propulsive efficiency, this efficiency is calculated under various conditions of flight with allowance for all internal losses. The efficiency and consumption curves are plotted, their practical values discussed and the behavior of the system analyzed at various altitudes and speeds. The immediate possibilities of the new system in flight at high and very high altitudes in relation to the theoretical and experimental results are discussed in detail. digital.library.unt.edu/ark:/67531/metadc63097/
Annual Report of the Explosives Division, Fiscal Year 1942
Report issued by the U.S. Bureau of Mines on the annual report of work conducted by the Explosives Division during the fiscal year of 1942. Descriptions of testing projects and operations are presented. This report includes tables, graphs, illustrations, and photographs. digital.library.unt.edu/ark:/67531/metadc38446/
Annual Report of the Mining Division, Fiscal Year 1942
Report issued by the U.S. Bureau of Mines on the annual work conducted by the Mining Division during 1942. Descriptions of projects and operations during the fiscal year are listed. This report contains tables, and photographs. digital.library.unt.edu/ark:/67531/metadc38445/
Annual report of the National Advisory Committee for Aeronautics (27th).administrative report including Technical Report nos. 704 to 726
Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report. digital.library.unt.edu/ark:/67531/metadc66364/
Application of Balancing Tabs to Ailerons
Analysis was made to determine characteristics required of a balancing-tab system for ailerons in order to reduce aileron stick forces to any desired magnitude. Series of calculations based on section data were made to determine balancing-tab systems of various chord tabs and ailerons that will give, for a particular airplane, zero rate of aileron hinge moment with aileron deflection and yet will produce same maximum rate of roll as a plain unbalanced 15-percent chord aileron of same span. Effects of rolling velocity and of forces in tab link on aileron hinge moments have been included. digital.library.unt.edu/ark:/67531/metadc61604/
Beam and torsion tests of aluminum-alloy 615-T tubing
Tests were made to determine the effect of length and the effect of ratios of diameter to wall thickness upon the flexural and torsional moduli of failure of 61S-T aluminum-alloy tubing. The moduli of failure in bending, as determined by tests in which the tubing was loaded on the neutral axis at the one-third points of the span, were found to bear an approximately linear relationship with diameter-thickness ratio and were practically independent of span within the limits investigated. Empirical equations are given describing the relations obtained. The moduli of failure in torsion were found to be dependent upon length as well as upon diameter-thickness ratios. Empirical equations are given for predicting strengths within the range of plastic buckling. Within the elastic range, available torsion theories were found to be satisfactory. digital.library.unt.edu/ark:/67531/metadc64916/
Bending of rectangular plates with large deflections
The solution of Von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to Von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, Mcpherson, and Levy. The deflections of a square plate under lateral pressure are compared with experimental and theoretical results by Kaiser. It is found that the effective widths agree closely with Marguerre's formula and with the experimentally observed values and that the deflections agree with the experimental results and with Kaiser's work. digital.library.unt.edu/ark:/67531/metadc59995/
Bending of Rectangular Plates with Large Deflections
The solution of von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, McPherson, and Levy. The deflections for a square plate under lateral pressure are compared with experimental and theoretical results by Kaiser. It is found that the effective widths agree closely with Marguerre's formula and with the experimentally observed values and that the deflections agree with the experimental results and with Kaiser's work. digital.library.unt.edu/ark:/67531/metadc54744/
Bending tests of a monocoque box
A monocoque box beam consisting of a 24S-T aluminum-alloy sheet reinforced by four bulkheads and by longitudinal stringers and corner posts was subjected to bending loads as follows: pure bending about the lift axis, cantilever bending about the lift axis, and pure bending about both lift and drag axis. Longitudinal strains were measured for loads up to a load at which permanent set became measurable. The loads were sufficient to produce buckling of the sheet between stringers on the compression side of the box. The only noticeable effect of this buckling was a small increase in extreme-fiber strain on the compression side. The measured strains and measured deflections differed less than 10 percent from those computed from the simple beam theory after taking account of the effective width of the buckled sheet. The effect of the bulkheads on the distribution of stringer strain was negligible. digital.library.unt.edu/ark:/67531/metadc57321/
Bending with large deflection of a clamped rectangular plate with length-width ratio of 1.5 under normal pressure
The Von Karman equations for a thin flat plate with large deflections are solved for the special case of a plate with clamped edges having a ratio of length to width of 1.5 and loaded by uniform normal pressure. Center deflections, membrane stresses, and extreme-fiber bending stresses are given as a function of pressure for center deflections up to twice the thickness of the plate. For small deflections the results coincide with those obtained by Hencky from the linear theory. The maximum stresses and center deflection at high pressures differ less than 3 percent from those derived by Bostnov for an infinitely long plate with clamped edges. This agreement suggests that clamped plates with a length-to-width ratio greater than 1.5 may be reared as infinitely long plates for purposes of design. digital.library.unt.edu/ark:/67531/metadc56606/
A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report
As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required. digital.library.unt.edu/ark:/67531/metadc65165/
Calculated effects of full-span slotted and Fowler flaps on longitudinal stability and control characteristics for a typical fighter-type airplane with various tail modifications
No Description digital.library.unt.edu/ark:/67531/metadc60928/
Calculation of tab characteristics for flight conditions from wind-tunnel data
No Description digital.library.unt.edu/ark:/67531/metadc61536/
Calibration of three temperature probes and a pressure probe at high speeds
No Description digital.library.unt.edu/ark:/67531/metadc62397/
Calibrations of pitot-static tubes at high speeds
No Description digital.library.unt.edu/ark:/67531/metadc62399/
Characteristics of beveled-trailing-edge elevators on a typical pursuit fuselage at altitudes simulating-normal flight and spin conditions
No Description digital.library.unt.edu/ark:/67531/metadc61603/
Characteristics of plain and balanced elevators on a typical pursuit fuselage at attitudes simulating normal-flight and spin conditions
No Description digital.library.unt.edu/ark:/67531/metadc61600/
The Characteristics of Two Model Six-Blade Counterrotating Pusher Propellers of Conventional and Improved Aerodynamic Design
Two airfoil plans were used for propeller blades. One is modified Clark Y section designed for structural reliability and the second an NACA 16 airfoil section designed to produce minimum aerodynamic losses. At low air speeds, the propeller designed for aerodynamic effects showed a gain of from 1.5 to 4.0 percent in propulsive efficiency over the conventional type depending on the pitch. Because of the numerous variables involved, the effect of each one on the aerodynamic characteristics of the propellers could not be isolated. digital.library.unt.edu/ark:/67531/metadc62164/
Coal-Mine Accidents in the United States, 1939
Report compiled by the U.S. Bureau of Mines including statistics on fatal and non-fatal accidents in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary. digital.library.unt.edu/ark:/67531/metadc12604/
Coal-Mine Accidents in the United States, 1940
Report compiled by the U.S. Bureau of Mines including statistics on fatal and non-fatal accidents in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary. digital.library.unt.edu/ark:/67531/metadc12608/
Column strength of magnesium alloy AM-57S
Tests were made to determine the column strength of extruded magnesium alloy AM-57S. Column specimens were tested with round ends and with flat ends. It was found that the compressive properties should be used in computations for column strengths rather than the tensile properties because the compressive yield strength was approximately one-half the tensile yield strength. A formula for the column strength of magnesium alloy AM-57S is given. digital.library.unt.edu/ark:/67531/metadc54684/
Comparison of Intercooler Characteristics
No abstract available. digital.library.unt.edu/ark:/67531/metadc62066/
A comparison of the results from general tank tests of 1/6- and 1/12-full-size models of the British Singapore IIC flying boat
A 1/6-full-size model of the hull of the British Singapore IIC flying boat was tested in the NACA tank. The results are given in the form of charts and are compared with the results of previous tests made in the NACA tank of a 1/12-full-size model, published in NACA T.N. No. 580, and with the results of tests made in the British R.A.E. tank of another 1/6-full-size model of the same hull. When the data from the tests of the 1/6- and 1/12-full-size models were compared on the basis of Froude's law of comparison, differences were found. This fact supported the belief that the small scale of the model and the use of a model that was too small to suit the equipment of the NACA tank had caused the results of the tests of the 1/12-full-size model to be less reliable than the results of the tests of the 1/6-full-size model. The results of the tests of the two models agreed sufficiently well to show that test of a small model, if made meticulously and with suitable equipment, may give useable results, but that a larger model should be used whenever feasible. The results of the NACA tests of the 1/6-full-size model were found to be in good agreement with the R.A.E. tests of a model of the same size. digital.library.unt.edu/ark:/67531/metadc54653/
Comparison of tightness of 78 degrees machine-countersunk rivets driven in holes prepared with 78 degrees and 82 degrees countersinking tools
No Description digital.library.unt.edu/ark:/67531/metadc62575/
The Compressible Potential Flow Past Elliptic Symmetrical Cylinders at Zero Angle of Attack and with No Circulation
For the tunnel corrections of compressible flows those profiles are of interest for which at least the second approximation of the Janzen-Rayleigh method can be applied in closed form. One such case is presented by certain elliptical symmetrical cylinders located in the center of a tunnel with fixed walls and whose maximum velocity, incompressible, is twice the velocity of flow. In the numerical solution the maximum velocity at the profile and the tunnel wall as well as the entry of sonic velocity is computed. The velocity distribution past the contour and in the minimum cross section at various Mach numbers is illustrated on a worked out-example. digital.library.unt.edu/ark:/67531/metadc63888/
Condensation trails : where they occur and what can be done about them
No Description digital.library.unt.edu/ark:/67531/metadc61828/
Construction of finned aluminum muffs for aircraft engine cylinder barrels
No Description digital.library.unt.edu/ark:/67531/metadc61901/
Contribution to the Design of Plywood Shells
The writer sets out to prove by calculation and experiment that by extensive utilization of the skin to carry axial load (reduction of stringer spacing) the stringer sections can be made small enough to afford a substantial saving in structural weight. This saving ranges from 5 to about 40 percent. digital.library.unt.edu/ark:/67531/metadc63889/
Contribution to the ideal efficiency of screw propellers
The stipulation of best thrust distribution is applied to the annular elements of the screw propeller with infinitely many blades in frictionless, incompressible flow and an ideal jet propulsion system derived possessing hyperbolic angular velocity distribution along the blade radius and combining the advantage of uniform thrust distribution over the section with minimum slipstream and rotation losses. This system is then compared with a propeller possessing the same angular velocity at all blade elements and the best possible thrust distribution secured by means of an induced efficiency varying uniformly over the radius. Lastly, the case of the lightly loaded propeller also is discussed. digital.library.unt.edu/ark:/67531/metadc63108/
Control-motion studies of the PBM-3 flying boat in abrupt pull-ups
No Description digital.library.unt.edu/ark:/67531/metadc60908/
Control of Torsional Vibrations by Pendulum Masses
Various versions of pendulum masses have been developed abroad within the past few years by means of which resonant vibrations of rotating shafts can be eliminated at a given tuning. They are already successfully employed on radial engines in the form of pendulous counterweights. Compared with the commonly known torsional vibration dampers, the pendulum masses have the advantage of being structurally very simple, requiring no internal damping and being capable of completely eliminating certain vibrations. Unexplained, so far, remains the problem of behavior of pendulum masses in other critical zones to which they are not tuned, their dynamic behavior at some tuning other than in resonance, and their effect within a compound vibration system and at simultaneous application of several differently tuned pendulous masses. These problems are analyzed in the present report. The results constitute an enlargement of the scope of application of pendulum masses, especially for in-line engines. Among other things it is found that the natural frequency of a system can be raised by means of a correspondingly tuned pendulum mass. The formulas necessary for the design of any practical version are developed, and a pendulum mass having two different natural frequencies simultaneously is described. digital.library.unt.edu/ark:/67531/metadc63949/
Cooling in cruising flight with low fuel-air ratios
No Description digital.library.unt.edu/ark:/67531/metadc61978/
Cooling investigation of a B-24D engine-nacelle installation in the NACA full-scale tunnel
No Description digital.library.unt.edu/ark:/67531/metadc62117/
Correlation of data on the statistical theory of turbulence
The statistical theory of turbulence affords an excellent medium for representing the kinematic conditions in turbulent flow and also serves as a valuable aid to exact experimental research. But it is still not developed enough for solving dynamic processes. Even in the simplest case of isotropic turbulence the calculation of the correlation curve or of the decrement of turbulence invariably reaches a point where clear-cut assumptions, such as omission of the inertia terms, or, earlier, mixing length assumptions or even merely general dimensional considerations, must be made. digital.library.unt.edu/ark:/67531/metadc63100/
The critical compression load for a universal testing machine when the specimen is loaded through knife edges
The results of a theoretical and experimental investigation to determine the critical compression load for a universal testing machine are presented for specimens loaded through knife edges. The critical load for the testing machine is the load at which one of the loading heads becomes laterally instable in relation to the other. For very short specimens the critical load was found to be less than the rated capacity given by the manufacturer for the machine. A load-length diagram is proposed for defining the safe limits of the test region for the machine. Although this report is particularly concerned with a universal testing machine of a certain type, the basic theory which led to the derivation of the general equation for the critical load, P (sub cr) = alpha L can be applied to any testing machine operated in compression where the specimen is loaded through knife edges. In this equation, L is the length of the specimen between knife edges and alpha is the force necessary to displace the upper end of the specimen unit horizontal distance relative to the lower end of the specimen in a direction normal to the knife edges through which the specimen is loaded. digital.library.unt.edu/ark:/67531/metadc54667/
Critical Compressive Stress for Flat Rectangular Plates Supported Along All Edges and Elastically Restrained Against Rotation along the Unloaded Edges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in flat rectangular plates supported along all edges and, in addition, elastically restrained against rotation along the unloaded edges. The mathematical derivations of the formulas required in the construction of the chart are given. digital.library.unt.edu/ark:/67531/metadc59990/
Critical Compressive Stress for Outstanding Flanges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given. digital.library.unt.edu/ark:/67531/metadc59989/
The cross-flow plate-type intercooler
No Description digital.library.unt.edu/ark:/67531/metadc62071/
Curing of resin-wood combinations by high-frequency heating
No Description digital.library.unt.edu/ark:/67531/metadc54769/
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