Search Results

open access

Effect of Rate of Temperature Change on the Transformations in an Alloy Steel

Description: Scientific paper issued by the Bureau of Standards over studies conducted on the effects of temperature change on alloy steel. The experimental methods used and the results are presented and discussed. This paper includes tables, photographs, and illustrations.
Date: July 10, 1919
Creator: Scott, Howard
Partner: UNT Libraries Government Documents Department
open access

Effect of variation of chord and span of ailerons on rolling and yawing moments in level flight

Description: This report presents the results of an investigation of the rolling and yawing moments due to ailerons of various chords and spans on two airfoils having the Clark Y and U. S. A. 27 wing sections. Some attention is devoted to a study of the effect of scale on rolling and yawing moments and to the effect of slightly rounding the wing tips. The results apply to level flight with the wing chord set at an angle of attack of +4 degrees and to conditions of zero pitch, zero yaw, and zero roll of the airplane. It is planned later to extend the investigation to other attitudes for monoplane and biplane combinations. The work was conducted in the 10 foot wind tunnel of the Bureau of Standards on models of 60-inch span and 10-inch chord. (author).
Date: July 10, 1928
Creator: Heald, R. H. & Strother, D. H.
Partner: UNT Libraries Government Documents Department
open access

Full-scale wind-tunnel tests of a propeller with the diameter changed by cutting off the blade tips

Description: Tests were conducted in order to determine how the characteristics of a propeller are affected by cutting off the tips. The diameter of a standard 10-foot metal propeller was changed successively to 9 feet 6 inches, 9 feet 0 inches, 8 feet 6 inches, and 8 feet 0 inches. Each propeller thus formed was tested at four pitch settings using an open cockpit fuselage and a D-12 engine. A small loss in propulsive efficiency is indicated. Examples are given showing the application of the results to practical problems.
Date: December 10, 1929
Creator: Wood, Donald H.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Research Comparing Lateral Control Devices, Particularly at High Angles of Attack 1: Ordinary Ailerons on Rectangular Wings

Description: "This report is the first in a series in which it is intended to compare the relative merits of all ordinary and some special forms of ailerons and other lateral control devices in regard to their effect on lateral controllability, lateral stability, and airplane performance. The comparisons are based on wind-tunnel test data, all the control devices being fitted to model wings having the same span, area, and airfoil section, and being subjected to the same series of force and rotation tests. The results are given for five different aileron movements: one with equal up-and-down deflection, one with average and one with extreme differential motion, one with upward deflection only, and one with the ailerons arranged to float with respect to the wing" (p. 357).
Date: December 10, 1931
Creator: Weick, Fred E. & Wenzinger, Carl J.
Partner: UNT Libraries Government Documents Department
open access

Increasing the air charge and scavenging the clearance volume of a compression-ignition engine

Description: The object of the investigation presented in this report was to determine the effects of increasing the air charge and scavenging the clearance volume of a 4-stroke-cycle compression-ignition engine having a vertical-disk form combustion chamber. Boosting the inlet-air pressure with normal valve timing increased the indicated engine power in proportion to the additional air inducted and resulted in smoother engine operation with less combustion shock. Scavenging the clearance volume by using a valve overlap of 145 degrees and an inlet-air boost pressure of approximately 2 1/2 inches of mercury produced a net increase in performance for clear exhaust operation of 33 percent over that obtained with normal valve timing and the same boost pressure. The improved combustion characteristics result in lower specific fuel consumption, and a clearer exhaust.
Date: June 10, 1933
Creator: Spanogle, J. A.; Hicks, C. W. & Foster, H. H.
Partner: UNT Libraries Government Documents Department
open access

Strength Tests of Thin-Walled Duralumin Cylinders in Compression

Description: "This report is the second of a series presenting the results of strength tests of thin-walled duralumin cylinders and truncated cones of circular and elliptic section. It contains the results obtained from compression tests on 45 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. In addition to the tests on duralumin cylinders, there are included the results of numerous tests on rubber, celluloid, steel, and brass cylinders obtained from various sources" (p. 585).
Date: June 10, 1933
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Tests on Combinations of a Wing With Fixed Auxiliary Airfoils Having Various Chords and Profiles

Description: This report presents the results of wind tunnel tests on various auxiliary airfoils having three different airfoil sections and several different chord lengths in combination with a Clark Y model wing in a sufficient number of relative positions to determine the optimum with regard to certain criterions of aerodynamic performance. The airfoil sections included a symmetrical profile, one of medium camber, and a highly cambered one. The chord sizes of the auxiliary airfoils ranged from 7.5 to 25 percent of the chord of the main wing, and the span was equal to that of the main wing.
Date: June 10, 1933
Creator: Weick, Fred E. & Sanders, Robert
Partner: UNT Libraries Government Documents Department
open access

A Flight Investigation of the Effect of Mass Distribution and Control Setting on the Spinning of the XN2Y-1 Airplane

Description: "The investigation of the effect of mass distribution on the spinning of airplanes initiated with tests on the NY-1 airplane has been continued by tests on another airplane in order to increase the scope of the information and to observe particularly the behavior of an airplane that shows considerable change in sideslip angle for its various conditions of spinning. The XN2Y-1 naval training biplane was used for the present tests in which changes of ballast along the longitudinal and lateral axes and changes of aileron, stabilizer, and elevator settings were made. The effects of these changes on the steady spin were measured in flight' (p. 185).
Date: January 10, 1934
Creator: Scudder, N. F.
Partner: UNT Libraries Government Documents Department
open access

Analysis of 2-Spar Cantilever Wings With Special Reference to Torsion and Load Transference

Description: "This paper deals with the analysis of 2-spar cantilever wings in torsion, taking cognizance of the fact that the spars are not independent, but are interconnected by ribs and other structural members. The principles of interaction are briefly explained, showing that the mutual relief action occurring depends on the "pure torsional stiffness" of the wing cross section. Various practical methods of analysis are outlined" (p. 45).
Date: April 10, 1934
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department
open access

Vibration response of airplane structures

Description: This report presents test results of experiments on the vibration-response characteristics of airplane structures on the ground and in flight. It also gives details regarding the construction and operation of vibration instruments developed by the National Advisory Committee for Aeronautics.
Date: May 10, 1934
Creator: Theodorsen, Theodore & Gelalles, A. G.
Partner: UNT Libraries Government Documents Department
open access

General equations for the stress analysis of rings

Description: In this report it is shown that the shear, axial force, and moment at one point in a simple ring subjected to any loading condition can be given by three independent equations involving certain integrals that must be evaluated regardless of the method of analysis used. It is also shown how symmetry of the ring alone or of the ring and the loading about 1 or 2 axes makes it possible to simplify the three equations and greatly reduces the number of integrals that must be evaluated. Application of the general equations presented in this report to practical problems in the stress analysis of rings makes it possible to shorten, simplify, and systematize the calculations for both simple and braced rings. Three illustrative problems are included to demonstrate the application of the general equations to a simple ring with different loadings.
Date: August 10, 1934
Creator: Lundquist, Eugene E. & Burke, Walter F.
Partner: UNT Libraries Government Documents Department
open access

Experimental investigation of the Robinson-type cup anemometer

Description: This report presents the results of wind tunnel tests on a Robinson-type anemometer. The investigation covered force measurements on individual cups, as well as static and dynamic torque measurements and calibrations on complete cup wheels. In the tests on individual cups 5 cup forms were used and in the measurements on complete cup wheels 4 cup wheels with 3 arm lengths for each cup wheel were tested. All the results are presented in graphical form.
Date: October 10, 1934
Creator: Brevoort, M. J. & Joyner, U. T.
Partner: UNT Libraries Government Documents Department
open access

The Effect of Water Vapor on Flame Velocity in Equivalent Carbon Monoxide and Oxygen Mixtures

Description: This report presents the results of an investigation to study the effect of water vapor upon the spatial speed of flame in equivalent mixtures of carbon monoxide and oxygen at various total pressures from 100 to 780 mm.hg. These results show that, within this pressure range, an increase in flame speed is produced by increasing the mole fraction of water vapor at least as far as saturation at 25 degrees c., and that the rate of this increase is greater the higher the pressure. It is evident that water vapor plays an important part in the explosive oxidation of carbon monoxide; the need for further experimental evidence as to the nature of its action is indicated.
Date: January 10, 1935
Creator: Fiock, Ernest F. & King, H. Kendall
Partner: UNT Libraries Government Documents Department
open access

The Soap-Bubble Method of Studying the Combustion of Mixtures of Carbon Monoxide and Oxygen

Description: This investigation is a detailed description of the soap-bubble, or constant-pressure, method as applied to the explosive oxidation of carbon monoxide. A series of values of the speed of flame in space in various mixtures of CO and O2 containing a constant percentage of water vapor was obtained by the constant-volume method. These results served as a guide in the perfection of the soap-bubble method.
Date: January 10, 1935
Creator: Fiock, Ernest F. & Roeder, Carl H.
Partner: UNT Libraries Government Documents Department
open access

Investigation of Full-Scale Split Trailing-Edge Wing Flaps With Various Chords and Hinge Locations

Description: This report gives the results of an investigation conducted in the NACA full-scale wind tunnel on a small parasol monoplane equipped with three different split trailing-edge wing flaps. The object of the investigation was to determine and correlate data on the characteristics of the airplane and flaps as affected by variation in flap chord, flap deflection, and flap location along the wing chord. The results give the lift, the drag, and the pitching moment characteristics of the airplane, and the flap forces and moments, the pressure distribution over the flaps and wing at one section, and the downwash characteristics of the flap and wing combinations.
Date: May 10, 1935
Creator: Wallace, Rudolf
Partner: UNT Libraries Government Documents Department
open access

A study of the torque equilibrium of an autogiro rotor

Description: From Summary: "Two improvements have been made in the method developed in NACA Reports nos. 487 and 591 for the estimation of the inflow velocity required to overcome a given decelerating torque in an autogiro rotor. At low tip-speed ratios, where the assumptions necessary for the analytical integrations of the earlier papers are valid, the expressions therein derived are greatly simplified by combining and eliminating terms with a view of minimizing the numerical computations required. At high tip-speed ratios, by means of charts based on graphical integrations, errors inherent in the assumptions associated with the analytical method are largely eliminated."
Date: January 10, 1938
Creator: Bailey, F. J., Jr.
Partner: UNT Libraries Government Documents Department
open access

The influence of directed air flow on combustion in spark-ignition engine

Description: "The air movement within the cylinder of the NACA combustion apparatus was regulated by using shrouded inlet valves and by fairing the inlet passage. Rates of combustion were determined at different inlet-air velocities with the engine speed maintained constant and at different engine speeds with the inlet-air velocity maintained approximately constant. The rate of combustion increased when the engine speed was doubled without changing the inlet-air velocity; the observed increase was about the same as the increase in the rate of combustion obtained by doubling the inlet-air velocity without changing the engine speed" (p. 313).
Date: October 10, 1938
Creator: Rothrock, A. M. & Spencer, R. C.
Partner: UNT Libraries Government Documents Department
open access

Preliminary wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of venetian-blind flaps

Description: Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of a large-chord NACA 23012 airfoil with several arrangements of venetian-blind flaps to determine the aerodynamic section characteristics as affected by the over-all flap chord, the chords of the slats used to form the flap, the slat spacing, the number of slats and the position of the flap with respect to the wing. Complete section data are given in the form of graphs for all the combinations tested.
Date: January 10, 1939
Creator: Wenzinger, Carl J. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of NACA 23012, 23021, and 23030 airfoils with various sizes of split flap

Description: Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of large-chord NACA and 23021, and 23030 airfoils with split flaps 10, 20, 30, and 40 percent of the wing chord to determine the section aerodynamic characteristics of the airfoils as affected by airfoil thickness, flap chord, and flap deflection. The complete section aerodynamic characteristics of all the combinations tested are given in the form of graphs of lift, drag, and pitching-moment coefficients, and certain applications to aerodynamic design are discussed.
Date: March 10, 1939
Creator: Wenzinger, Carl J. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
open access

Normal-pressure tests of circular plates with clamped edges

Description: A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness form 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of the permanent set as a function of the dimensions of the plate and the tensile properties of the material.
Date: October 10, 1941
Creator: McPherson, Albert E.; Ramberg, Walter & Levy, Samuel
Partner: UNT Libraries Government Documents Department
open access

Effective Temperature of Neutrons in a Lattice

Description: The average energies of neutrons emitted from a graphite column at 22 degrees C were compared by measurement of the cross section of boron for neutrons which are stopped by cadmium. At a distance from the neutron source great enough to insure that the neutrons were in thermal equilibrium the average energies of the emerging neutrons were found to be proportional to the temperature within the limits of the experimental error. A measurement made with boron absorbers which had been thus standardized in the graphite column indicated neutrons emerging from the chain reacting pile to have an average temperature approximate 60 +- 50 degrees above that of thermal neutrons emerging from the graphite column at 22 degrees C. Such a measurement made inside the chain reacting pile indicated the average temperature of neutrons therein to be about 65 degrees +- 15 degrees above the average temperature of neutrons in the graphite column.
Date: February 10, 1943
Creator: Woods, L.
Partner: UNT Libraries Government Documents Department
open access

Temperature Coefficient of the Reproduction Factor for Different Lattice Arrangements

Description: The temperature coefficient is calculated for various lattice arrangements, taking into account the variation of [formula], suggested by Fermi. Four contributions are included: leakage, levelling of the dip in thermal neutron density in the lump, resonance absorption, and hardening of the neutrons as they penetrate a metal lump. The departure of neutron temperature from lattice temperature decreases the total coefficient. Values are given for 3 typical piles; in general, the larger the uranium elements, the less stable the pile. A rod lattice tends to be more stable. A pile with metal lumps over 50 lbs. will be unstable.
Date: February 10, 1943
Creator: Morrison, P.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen