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  Partner: UNT Libraries Government Documents Department
 Collection: Technical Report Archive and Image Library
Some torsional-damping measurements of laminated beams as applied to the propeller stall-flutter problem
The structural damping in the torsion mode of vibration of a series of untwisted, laminated thin beams simulating propeller blades is presented. The number of lamination were varied, as well as the bonding material and the method of joining lamination. Application of the data to the calculation of the minimum flutter speed of thin propeller blades indicates that appreciable gains in the minimum flutter speed may be obtained for laminated blades using a Cycleweld bond. digital.library.unt.edu/ark:/67531/metadc59590/
Some transonic aerodynamic charcteristics of a model similar to the mcdonnell f3h-2n airplane
No Description digital.library.unt.edu/ark:/67531/metadc53015/
Some wind-tunnel experiments on single-degree-of-freedom flutter of ailerons in the high subsonic speed range
No Description digital.library.unt.edu/ark:/67531/metadc55941/
Some wind-tunnel results of an investigation of the flutter of sweptback- and triangular-wing models at Mach number 1.3
No Description digital.library.unt.edu/ark:/67531/metadc59218/
Some yawing tests of a 1/30-scale model of the hull of the XPB2M-1 flying boat
No Description digital.library.unt.edu/ark:/67531/metadc62669/
The sonic altimeter for aircraft
Discussed here are results already achieved with sonic altimeters in light of the theoretical possibilities of such instruments. From the information gained in this investigation, a procedure is outlined to determine whether or not a further development program is justified by the value of the sonic altimeter as an aircraft instrument. The information available in the literature is reviewed and condensed into a summary of sonic altimeter developments. Various methods of receiving the echo and timing the interval between the signal and the echo are considered. A theoretical discussion is given of sonic altimeter errors due to uncertainties in timing, variations in sound velocity, aircraft speed, location of the sending and receiving units, and inclinations of the flight path with respect to the ground surface. Plots are included which summarize the results in each case. An analysis is given of the effect of an inclined flight path on the frequency of the echo. A brief study of the acoustical phases of the sonic altimeter problem is carried through. The results of this analysis are used to predict approximately the maximum operating altitudes of a reasonably designed sonic altimeter under very good and very bad conditions. A final comparison is made between the estimated and experimental maximum operating altitudes which shows good agreement where quantitative information is available. digital.library.unt.edu/ark:/67531/metadc54351/
A sonic-flow orifice probe for the in-flight measurements of temperature profiles of a jet engine exhaust with afterburning
No Description digital.library.unt.edu/ark:/67531/metadc56007/
Sonic-flow-orifice temperature probe for high-gas-temperature measurements
No Description digital.library.unt.edu/ark:/67531/metadc55510/
Sound from a two-blade propeller at supersonic tip speeds
Report presents the results of sound measurements at static conditions made for a two-blade 47-inch-diameter propeller in the tip Mach number range 0.75 to 1.30. For comparison, spectrums have been obtained at both subsonic and supersonic tip speeds. In addition, the measured data are compared with calculations by the theory of Gutin which has previously been found adequate for predicting the sound at subsonic tip speeds. Curves are presented from which the maximum over-all noise levels in free space may be estimated if the power, tip Mach number, and distance are known. digital.library.unt.edu/ark:/67531/metadc60441/
Sound from a two-blade propeller at supersonic tip speeds
No Description digital.library.unt.edu/ark:/67531/metadc58787/
Sound from dual-rotating and multiple single-rotating propellers
No Description digital.library.unt.edu/ark:/67531/metadc54657/
Sound Insulation of Wall and Floor Constructions
No Description digital.library.unt.edu/ark:/67531/metadc40304/
Sound Insulation of Wall, Floor, and Door Constructions
No Description digital.library.unt.edu/ark:/67531/metadc13262/
Sound-level measurements of a light airplane modified to reduce noise reaching the ground
An Army liaison-type airplane, representative of personal airplanes in the 150 to 200 horsepower class, has been modified to reduce propeller and engine noise according to known principles of airplane-noise reduction. Noise-level measurements demonstrate that, with reference to an observer on the ground, a noisy airplane of this class can be made quiet -- perhaps more quiet than necessary. In order to avoid extreme and unnecessary modifications, acceptable noise levels must be determined. digital.library.unt.edu/ark:/67531/metadc60240/
Sound-level measurements of a light airplane modified to reduce noise reaching the ground
No Description digital.library.unt.edu/ark:/67531/metadc54635/
Sound measurements for five shrouded propellers at static conditions
No Description digital.library.unt.edu/ark:/67531/metadc55335/
A sound pressure-level meter without amplification
The N.A.C.A. has developed a simple pressure-level meter for the measurement of sound-pressure levels above 70 db. The instrument employs a carbon microphone but has no amplification. The source of power is five flashlight batteries. Measurements may be made up to the threshold of feeling with an accuracy of plus or minus 2 db; band analysis of complex spectra may be made if desired. digital.library.unt.edu/ark:/67531/metadc54427/
Sound propagation into the shadow zone in a temperature-stratified atmosphere above a plane boundary
No Description digital.library.unt.edu/ark:/67531/metadc57873/
The source of propeller noise
A two blade propeller of 40 cm diameter and zero pitch was explored for its noise development; it could be whirled up to 17,000 rpm - i.e., a tip speed of 355 meters/second. To obtain the power loss N(sub m) of the propeller for comparison with the produced acoustical power N(sub A) the engine performance characteristics were measured with and without propeller. The result is the sought-for relation c, that is, curve c' after correction with the engine efficiency. digital.library.unt.edu/ark:/67531/metadc63372/
Source Strength Information for Shielding and Stack Effluent Calculations: a Standard Practices Guide
Report presenting the curves and methods used "for determining gross fission product gamma energy in Mev/sec-watt, gross fission product beta decay in curies/sec-watt, delayed uranium fission neutrons in neutrons/sec-watt and N16 and N17 decay in photons/sec-cc of water" (p. 1). digital.library.unt.edu/ark:/67531/metadc67280/
Sources of Limestone, Gypsum, and Anhydrite for Dusting Coal Mines to Prevent Explosions
No Description digital.library.unt.edu/ark:/67531/metadc12427/
South Loop New Town Urban Pollutant Study: Status Report. Comparison of Two Proposed Franklin St. Connector Alternatives
Preliminary results are given of a study of probable carbon monoxide pollution concentrations in the South Loop area that may arise from either of two alternative Franklin Street Connector plans proposed by the Chicago Bureau of Street Traffic and by Alan M. Voorhees and Associates. digital.library.unt.edu/ark:/67531/metadc173336/
Southwest Experimental Fast Oxide Reactor Development Program: First Quarterly Report, April-June 1964
From abstract: "This report summarizes the work performed on the Research and Development Program for the Southwest Experimental Fast Oxide Reactor." digital.library.unt.edu/ark:/67531/metadc101096/
The Soviet Seven-Year Plan (1959-65) for Oil
Report issued by the Bureau of Mines discussing the Soviet plan to increase oil production between 1959 and 1965. As stated in the introduction, "this report, based almost entirely on Soviet petroleum literature, describes the planned expansion of the U.S.S.R. petroleum industry and attempts to provide some idea of the magnitude of future Soviet oil exports" (p. 2). This report includes tables, and a map. digital.library.unt.edu/ark:/67531/metadc67104/
Space Groups and Lattice Complexes
No Description digital.library.unt.edu/ark:/67531/metadc13174/
Space heating rates for some premixed turbulent propane-air flames
No Description digital.library.unt.edu/ark:/67531/metadc57123/
The spacing of orifices for the measure of pressure distributions
The following report has been prepared for publication by the NACA. Suitable locations of orifices for the measurement of pressure distributions have been discussed. Tables are given for quickly laying out these locations and for quickly and easily computing the resultant air forces from the result of the measurements. digital.library.unt.edu/ark:/67531/metadc53891/
The span as a fundamental factor in airplane design
Previous theoretical investigations of steady curvilinear flight did not afford a suitable criterion of "maneuverability," which is very important for judging combat, sport and stunt-flying airplanes. The idea of rolling ability, i.e., of the speed of rotation of the airplane about its X axis in rectilinear flight at constant speed and for a constant, suddenly produced deflection of the ailerons, is introduced and tested under simplified assumptions for the air-force distribution over the span. This leads to the following conclusions: the effect of the moment of inertia about the X axis is negligibly small, since the speed of rotation very quickly reaches a uniform value. digital.library.unt.edu/ark:/67531/metadc65281/
Span-load distribution as a factor in stability in roll
This report gives the results of pressure-distribution tests made to study the effects on lateral stability of changing the span-load distribution on a rectangular monoplane wing model of fairly thick section. Three methods of changing the distribution were employed: variation in profile along the span to a thin symmetrical section at the tip, twist from +5 degrees to -15 degrees at the tip, and sweepback from +20 degrees to -20 degrees. The tests were conducted in a 5-foot closed-throat atmospheric wind tunnel. The investigation shows the following results: (1) change in profile along the span from the NACA-84 at the root to the NACA-M2 at the tip considerably reduces lateral instability, but also reduces the general effectiveness of the wing. (2) washout up to 11 degrees progressively reduces maximum lateral instability. (3) transition from sweepforward to sweepback gradually reduces the useful angle-of-attack range, but has no clearly defined effect on maximum lateral instability. digital.library.unt.edu/ark:/67531/metadc66050/
Span load distribution for tapered wings with partial-span flaps
Tables are given for determining the load distribution of tapered wings with partial-span flaps placed either at the center or at the wing tips. Seventy-two wing-flap combinations, including two aspect ratios, four taper ratios, and nine flap lengths, are included. The distributions for the flapped wing are divided into two parts, one a zero lift distribution due primarily to the flaps and the other an additional lift distribution due to an angle of attack of the wing as a whole. Comparison between theoretical and experimental results for wings indicate that the theory may be used to predict the load distribution with sufficient accuracy for structural purposes. digital.library.unt.edu/ark:/67531/metadc66243/
Span load distribution on two monoplanes wing models as affected by twist and sweepback
The results presented in this note show the effect of twist and sweepback on the span load distribution over two monoplane wing models. The tests were made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The data are taken from the results of an investigation dealing primarily with lateral stability. As presented, they are suitable as an aid in the structural design of certain monoplane wings. digital.library.unt.edu/ark:/67531/metadc53968/
Span load distribution resulting from constant vertical acceleration for thin sweptback tapered wings with streamwise tips
No Description digital.library.unt.edu/ark:/67531/metadc57076/
Span load distributions resulting from angle of attack, rolling, and pitching for tapered sweptback wings with streamwise tips
No Description digital.library.unt.edu/ark:/67531/metadc56484/
Span load distributions resulting from constant angle of attack, steady rolling velocity, steady pitching velocity, and constant vertical acceleration for tapered sweptback wings with streamwise tips subsonic leading edges and supersonic trailing edg
No Description digital.library.unt.edu/ark:/67531/metadc56388/
The spanwise distribution of lift for minimum induced drag of wings having a given lift and a given bending moment
The problem of the minimum induced drag of wings having a given lift and a given span is extended to include cases in which the bending moment to be supported by the wing is also given. The theory is limited to lifting surfaces traveling at subsonic speeds. It is found that the required shape of the downwash distribution can be obtained in an elementary way which is applicable to a variety of such problems. Expressions for the minimum drag and the corresponding spanwise load distributions are also given for the case in which the lift and the bending moment about the wing root are fixed while the span is allowed to vary. The results show a 15-percent reduction of the induced drag with a 15-percent increase in span as compared with results for an elliptically loaded wing having the same total lift and bending moment. digital.library.unt.edu/ark:/67531/metadc53315/
The spanwise distribution of lift for minimum induced drag of wings having a given lift and a given bending moment
No Description digital.library.unt.edu/ark:/67531/metadc55624/
Spanwise loading for wings and control surfaces of low aspect ratio
No Description digital.library.unt.edu/ark:/67531/metadc55319/
Spark ignition of flowing gases
Research conducted at the NACA Lewis Laboratory on ignition of flowing gases by means of long-duration discharges is summarized and analyzed. Data showing the effect of a flowing combustible mixture on the physical and electrical characteristics of spark discharges and data showing the effects of variables on the spark energy required for ignition that has been developed to predict the effect of many of the gas-stream and spark variables is described and applied to a limited amount of experimental data. digital.library.unt.edu/ark:/67531/metadc60681/
Spark Ignition of Flowing Gases. 2: Effect of Electrode Parameters on Energy Required to Ignite a Propane-Air Mixture
Research was conducted to determine the effect of the electrode parameters of spacing, configuration, and material' on the energy required for ignition of a flowing propane-air mixture. In addition, the data were used to indicate the energy distribution along the spark length and to confirm previous observations concerning the effect of spark duration on ignition energy requirements. The data were obtained with a mixture at a fuel-air ratio of 0.0835 (by weight), a pressure of 3 inches of mercury absolute, a temperature of 80 F, and a mixture velocity of 5 feet per second. Results showed that the energy required for ignition decreased as the electrode spacing was increased; a minimum energy occurred at. a spacing of 0.65 inch for large electrodes. For small electrodes, the spacing for minimum energy was not sharply defined. Small-diameter electrodes required less energy than large-diameter electrodes if the spacing was less than the optimum distance of 0.65 inch; at a spacing equal to the optimum distance, no difference was noted. Significant effects of electrode material on ignition energy were ascribed to differences in the type of spark discharges produced; glow discharges required higher energy than the arc-glow discharges. With pure glow discharges, the ignition energy was substantially constant for lead, cadmium, brass, aluminum, and tungsten electrodes. A method is described for determining the energy distribution along a glow discharge. It was found that one-third to one-half of the energy in the spark was concentrated in a small region near the cathode electrode, and the remainder was uniformly distributed across the spark gap. It was impossible to ascertain the dependence of ignition on. this distribution. It was also observed that long-duration (600 microsec) sparks required much less energy for ignition than did short-duration (1 microsec) sparks. digital.library.unt.edu/ark:/67531/metadc53307/
Spark ignition of flowing gases I : energies to ignite propane-air mixtures in pressure range of 2 to 4 inches mercury absolute
Ignition studies of flowing gases were made to obtain information applicable to ignition problems in gas-turbine and ram-jet aircraft propulsion systems operating at altitude conditions.Spark energies required for ignition of a flowing propane-air mixture were determined for pressure of 2 to 4 inches mercury absolute, gas velocities of 5.0 to 54.2 feet per second, fuel-air ratios of 0.0607 to 0.1245, and spark durations of 1.5 to 24,400 microseconds. The results showed that at a pressure of 3 inches mercury absolute the minimum energy required for ignition occurred at fuel-air ratios of 0.08 to 0.095. The energy required for ignition increased almost linearly with increasing gas velocity. Shortening the spark duration from approximately 25,000 to 125 microseconds decreased the amount of energy required for ignition. A spark produced by the discharge of a condenser directly into the spark gap and having a duration of 1.5 microseconds required ignition energies larger than most of the long-duration sparks. digital.library.unt.edu/ark:/67531/metadc62806/
Spark ignition of flowing gases III : effect of turbulence promoter on energy required to ignite a propane-air mixture
No Description digital.library.unt.edu/ark:/67531/metadc59431/
Spark ignition of flowing gases V : application of fuel-air-ratio and initial-temperature data to ignition theory
No Description digital.library.unt.edu/ark:/67531/metadc61630/
Spark plug defects and tests
The successful operation of the spark plug depends to a large extent on the gas tightness of the plug. Part 1 of this report describes the method used for measuring the gas tightness of aviation spark plugs. Part 2 describes the methods used in testing the electrical conductivity of the insulation material when hot. Part 3 describes the testing of the cold dielectric strength of the insulation material, the resistance to mechanical shock, and the final engine test. digital.library.unt.edu/ark:/67531/metadc65702/
Spark-Source Mass Spectrometric Analysis of Common and Radiogenic Lead
Analysis that is fast and has extremely low levels of detection for more than forty elements that may be present in lead. digital.library.unt.edu/ark:/67531/metadc173338/
Spark-timing control based on correlation of maximum-economy spark timing, flame-front travel, and cylinder pressure rise
No Description digital.library.unt.edu/ark:/67531/metadc54350/
Spark-timing control based on correlation of maximum-economy spark timing, flame-front travel, and cylinder-pressure rise
An investigation was conducted on a full-scale air-cooled cylinder in order to establish an effective means of maintaining maximum-economy spark timing with varying engine operating conditions. Variable fuel-air-ratio runs were conducted in which relations were determined between the spark travel, and cylinder-pressure rise. An instrument for controlling spark timing was developed that automatically maintained maximum-economy spark timing with varying engine operating conditions. The instrument also indicated the occurrence of preignition. digital.library.unt.edu/ark:/67531/metadc60192/
The sparking voltage of spark plugs
This report has been prepared in order to collect and correlate into convenient and useful form the available data on this subject. The importance of the subject lies in the fact that it forms the common meeting ground for studies of the performance of spark generators and spark plugs on the one hand and of the internal combustion engines on the other hand. While much of the data presented was obtained from various earlier publications, numerous places were found where necessary data were lacking, and these have been provided by experiments in gasoline engines at the Bureau of Standards. digital.library.unt.edu/ark:/67531/metadc65853/
Spartan "Cruiser" commercial airplane (British) : a six-seat low-wing cantilever monoplane
No Description digital.library.unt.edu/ark:/67531/metadc279559/
Spatial buckling of various types of airplane strut systems
Equations are presented for two and three dimensional strut systems along with tables of equations. digital.library.unt.edu/ark:/67531/metadc277452/
Spatial Burnout in Water Reactors with Nonuniform Startup Distributions of Uranium and Boron
Spatial burnout calculations have been made of two types of water moderated cylindrical reactor using boron as a burnable poison to increase reactor life. Specific reactors studied were a version of the Submarine Advanced Reactor (sAR) and a supercritical water reactor (SCW) . Burnout characteristics such as reactivity excursion, neutron-flux and heat-generation distributions, and uranium and boron distributions have been determined for core lives corresponding to a burnup of approximately 7 kilograms of fully enriched uranium. All reactivity calculations have been based on the actual nonuniform distribution of absorbers existing during intervals of core life. Spatial burnout of uranium and boron and spatial build-up of fission products and equilibrium xenon have been- considered. Calculations were performed on the NACA nuclear reactor simulator using two-group diff'usion theory. The following reactor burnout characteristics have been demonstrated: 1. A significantly lower excursion in reactivity during core life may be obtained by nonuniform rather than uniform startup distribution of uranium. Results for SCW with uranium distributed to provide constant radial heat generation and a core life corresponding to a uranium burnup of 7 kilograms indicated a maximum excursion in reactivity of 2.5 percent. This compared to a maximum excursion of 4.2 percent obtained for the same core life when w'anium was uniformly distributed at startup. Boron was incorporated uniformly in these cores at startup. 2. It is possible to approach constant radial heat generation during the life of a cylindrical core by means of startup nonuniform radial and axial distributions of uranium and boron. Results for SCW with nonuniform radial distribution of uranium to provide constant radial heat generation at startup and with boron for longevity indicate relatively small departures from the initially constant radial heat generation distribution during core life. Results for SAR with a sinusoidal distribution rather than uniform axial distributions of boron indicate significant improvements in axial heat generation distribution during the greater part of core life. 3. Uranium investments for cylindrical reactors with nonuniform radial uranium distributions which provide constant radial heat generation per unit core volume are somewhat higher than for reactors with uniform uranium concentration at startup. On the other hand, uranium investments for reactors with axial boron distributions which approach constant axial heat generation are somewhat smaller than for reactors with uniform boron distributions at startup. digital.library.unt.edu/ark:/67531/metadc65307/