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The Unsteady Lift of a Finite Wing
Note discussing the lift of a finite wing including the calculations and constants for each step of the lift. This information is compared against the lift of an infinite wing. From Summary: "Unsteady lift function for wings of finite aspect ratio have been calculated by approximate methods involving corrections of the aerodynamic inertia and of the angle of the infinite wing. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the final lift may be considerably less. The calculations indicate that the distribution of lift near the start is similar to the final distribution."
Date:
January 1939
Creator:
Jones, Robert T.
System:
The UNT Digital Library
Column and Plate Compressive Strengths of Aircraft Structural Materials: Extruded 0-1HTA Magnesium Alloy
Column and plate compressive strengths of extruded 0-1HTA magnesium alloy were determined both within and beyond the elastic range from tests of flat end H-section columns and from local instability tests of H-, Z-, and channel section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.
Date:
January 1947
Creator:
Heimerl, George J. & Niles, Donald E.
System:
The UNT Digital Library
Corrosion tests of a heated wing utilizing an exhaust-gas-air mixture for ice prevention
Report presenting an investigation of the exhaust of corrosive attack in an aluminum alloy wing employing an exhaust-gas-air mixture as a heating medium for ice prevention. There were no cases of structurally serious corrosion on either painted or plain specimens removed from the wing for detailed microscopic and metallurgic examination.
Date:
January 1949
Creator:
Holdaway, George H.
System:
The UNT Digital Library
Study by the Prandtl-Glauert method of compressibility effects and critical Mach number for ellipsoids of various aspect ratios and thickness ratios
From Summary: "By the use of a form of the Prandtl-Glauert method that is valid for three-dimensional flow problems, the value of the maximum incremental velocity for compressible flow about thin ellipsoids at zero angle of attack is calculated as a function of the Mach number for various aspect ratios and thickness ratios. The critical Mach numbers (within the accuracy of the Prandtl-Glauert method) of the various ellipsoids are also determined. The results indicate an increase in critical Mach number with decrease in aspect ratio which is large enough to explain experimental results on low-aspect-ratio wings at zero lift."
Date:
January 1949
Creator:
Hess, Robert V. & Gardner, Clifford S.
System:
The UNT Digital Library
Investigation of Meteorological Conditions Associated with Aircraft Icing in Layer-Type Clouds for 1947-48 Winter
Rotating-cylinder measurements of the icing conditions encountered in flight during the winter of 1947-48 are presented. Liquid water content, drop size, and temperature data are shown to be consistent with previously measured conditions and with proposed maximum icing conditions in supercooled layer-type clouds. Cumulative frequency graphs of meteorological parameters indicate the frequency with which various icing conditions have been encountered in the Great Lakes area and surrounding states.
Date:
January 1949
Creator:
Kline, Dwight B.
System:
The UNT Digital Library
Gust-tunnel investigation of a wing model with semichord line swept back 30 degrees
Report presenting tests in the gust tunnel of the 30 degree sweptback wing model to provide information on some of the problems encountered in the prediction of gust loads for airplanes incorporating swept wings. The results indicate that within the scope of the data and the values of gradient distance investigated, the maximum acceleration increment depends on the slope of the lift curve of an equivalent straight wing multiplied by the cosine of the angle of sweep and on the effect of gradual penetration of the sweptback wing into the gust.
Date:
January 1949
Creator:
Reisert, Thomas D.
System:
The UNT Digital Library
The Synthesis and Purification of Aromatic Hydrocarbons 1: Butylbenzene
"A 13-gallon quantity of butylbenzene was synthesized and purified by large-scale preparation of 4-phenyl-1-butene from benzyl-magnesium chloride and allyl chloride with subsequent hydrogenation of the olefin. The physical constants for pure samples of 4-phenyl-1-butene and butylbenzene were determined and the position of the double bond in the olefin was established" (p. 1).
Date:
January 1946
Creator:
Karabinos, Joseph V. & Lamberti, Joseph M.
System:
The UNT Digital Library
Application of Radial-Equilibrium Condition to Axial-Flow Compressor and Turbine Design
Note presenting some of the basic general equations governing the three-dimensional compressible flow of gas through a compressor or a turbine in terms of velocity components, total enthalpy, and entropy. The equations are applied to investigate the maximum compatible number of the radial variations of the gas properties between successive blade rows that a designer is free to specify.
Date:
January 1949
Creator:
Wu, Chung-Hua & Wolfenstein, Lincoln
System:
The UNT Digital Library
Effect of hull length-beam ratio on the hydrodynamic characteristics of flying boats in waves
Report presenting an investigation of the take-off and landing behavior in waves of models of a hypothetical flying boat with hull length-beam ratios of 6 and 15. The flying boat had a design gross weight of 75,000 pounds, a wing loading of 41.1 pounds per square foot, and a power loading of 11.5 pounds per brake horsepower for take-off. Results regarding the landing behavior, spray characteristics, and taxiing and take-off behavior are provided.
Date:
January 1949
Creator:
Carter, Arthur W.
System:
The UNT Digital Library
Flight Investigation in Climb and at High Speed of a Two-Blade and a Three-Blade Propeller
Note presenting an investigation of a two-blade and a three-blade propeller on a slender-nose fighter airplane in climb and at high speed.
Date:
January 1949
Creator:
Hammack, Jerome B.
System:
The UNT Digital Library
Comparison of the structural efficiency of panels having straight-web and curved-web Y-section stiffeners
Report presenting comparisons of the structural efficiency of panels with straight-web and curved-web Y-section stiffeners. In the high-stress region in which failure is at least in part associated with local buckling, panels with curved-web Y-section stiffeners have higher structural efficiencies than panels with straight-web Y-section stiffeners, which is evidenced by higher average stresses at failure, smaller stiffener heights, or wider average spacing of rivet lines.
Date:
January 1949
Creator:
Dow, Norris F. & Hickman, William A.
System:
The UNT Digital Library
Tentative Tables for the Properties of the Upper Atmosphere
Note presenting three temperature-height relationships and one composition-height relationship developed by the NACA and tables based on them for pertinent properties of the upper atmosphere. Two sets of tables based on the adopted tentative standard specifications for the upper atmosphere are presented.
Date:
January 1947
Creator:
Warfield, Calvin N.
System:
The UNT Digital Library
The Synthesis and Purification of Aromatic Hydrocarbons 2: 1, 2, 4-Trimethylbenzene
Note presenting a new method for the synthesis and purification of a 14-gallon quantity of 1,2,4-trimethylbenzene. The method consists in the chloromethylation of m- and p-xylenes, subsequent formation of ethyl dimethylbenzyl ethers, and hydrogenolysis of the ethers to yield the hydrocarbon. Results regarding chloromethylation of xylene, conversion of dimethylbenzyl chlorides to ethyl dimethylbenzyl ethers, hydrogenolysis of the ethyl dimethylbenzyl ethers, and identification of biproducts are provided.
Date:
January 1946
Creator:
Ebersole, Earl R.
System:
The UNT Digital Library
Effect of brake forming in various tempers on the strength of Alclad 75S-T aluminum-alloy sheet
Results are presented of tests to determine the effect of brake forming in various tempers on the strength of Alclad 75S-T aluminum alloy sheet in the direction parallel to the brake. The tensile and compressive strengths of Alclad 75S-T sheet, formed in the O and W tempers, were either increased or little affected compared with those of similarly treated unformed material. When Alclad 75S-T sheet 'as received' was formed, however, the tensile yield stress was reduced about 7 percent for the with-grain direction and 1 percent for the cross-grain direction, whereas the tensile ultimate and compressive yield stresses were increased somewhat. The elongation was always slightly reduced as a result of forming.
Date:
January 1947
Creator:
Woods, Walter & Heimerl, George J.
System:
The UNT Digital Library
A Method for Studying the Transient Blade-Flapping Behavior of Lifting Rotors at Extreme Operating Conditions
Note presenting a method for studying the transient behavior of the flapping motion, as well as for calculating the steady-state flapping amplitudes, of free-to-cone and seesaw rotors operating at extreme flight conditions. The method is general and can be applied to blades of any airfoil section, mass distribution, twist, plan-form taper, root cutout, and flapping-hinge geometry.
Date:
January 1955
Creator:
Gessow, Alfred & Crim, Almer D.
System:
The UNT Digital Library
A General Theory of Three-Dimensional Flow in Subsonic and Supersonic Turbomachines of Axial-, Radial-, and Mixed-Flow Types
Note presenting a general theory of steady three-dimensional flow of a nonviscous fluid in subsonic and supersonic turbomachines with arbitrary hub and casing shapes and a finite number of blades. The equations obtained to describe the fluid flow on these stream surfaces show clearly the several approximations involved in ordinary two-dimensional treatments.
Date:
January 1952
Creator:
Wu, Chung-Hua
System:
The UNT Digital Library
Calculations on the forces and moments for an oscillating wing-aileron combination in two-dimensional potential flow at sonic speed
Report presenting the use of linearized theory for compressible unsteady flow to obtain the velocity potential and lift and moment for a thin, harmonically oscillating, two-dimensional wing-aileron combination moving at sonic speed.
Date:
January 1952
Creator:
Nelson, Herbert C. & Berman, Julian H.
System:
The UNT Digital Library
The effects of Reynolds number on the application of NACA 16-series airfoil characteristics to propeller design
Report presenting an analysis of airfoil data from several NACA 16-series propeller airfoils from tests of 5-inch chord models in the 24-inch high-speed tunnel and 12-inch-chord models in the 8-foot high-speed tunnel. Results indicated that differences of less than 1 percent in propeller efficiency at or near the design condition will be involved in applying data from 5-inch-chord and 12-inch-chord airfoil tests to full-scale propeller design.
Date:
January 1952
Creator:
Cleary, Harold E.
System:
The UNT Digital Library
Orientation of orifices on bodies of revolution for determination of stream static pressure at supersonic speeds
Report presenting experimental data obtained in the 4- by 4-foot supersonic tunnel for a parabolic body of revolution of large fineness ratio at mach number 1.59, which are analyzed in order to locate positions at which static-pressure orifices will indicate a constant static pressure independent of the pitch-yaw attitude of the body.
Date:
January 1952
Creator:
Cooper, Morton & Hamilton, Clyde V.
System:
The UNT Digital Library
Design of two-dimensional channels with prescribed velocity distribution along the channel walls 1: relaxation solutions
Report presenting a general method of design is developed for two-dimensional unbranched channels with prescribed velocities as a function of arc length along the channel walls. The method is developed for both incompressible and compressible, irrational, nonviscous flow. Five numerical examples are given including three elbow designs with the same prescribed velocity as a function of arc length along the channel walls but with incompressible, linearized compressible, and compressible flow.
Date:
January 1952
Creator:
Stanitz, John D.
System:
The UNT Digital Library
An Impulse-Momentum Method for Calculating Landing-Gear Contact Conditions in Eccentric Landings
"An impulse-momentum method for determining impact conditions for landing gears in eccentric landings is presented. The analysis is primarily concerned with the determination of contact velocities for impacts subsequent to initial touchdown in eccentric landings and with the determination of the effective mass acting on each landing gear. These parameters determine the energy-absorption requirements for the landing gear and, in conjunction with the particular characteristics of the landing gear, govern the magnitude of the ground loads" (p. 1).
Date:
January 1952
Creator:
Yntema, Robert T. & Milwitzky, Benjamin
System:
The UNT Digital Library
Investigation of Laminar Boundary Layer in Compressible Fluids Using the Crocco Method
Note presenting the use of the Crocco method to solve the simultaneous differential equations of momentum and energy involved in the flow of air in a thin laminar boundary layer on a flat plate. The Crocco method was used because it gave accurate results for arbitrary Prandtl number near unity. Variations of shear, velocity, temperature, and Mach number across the boundary layer are included.
Date:
January 1952
Creator:
Van Driest, E. R.
System:
The UNT Digital Library
Compressive buckling of simply supported curved plates and cylinders of sandwich construction
From Summary: "Theoretical solutions are presented for the buckling in uniform axial compression of two types of simply supported curved sandwich plates: the corrugated-core type and the isotropic-core type. The solutions are obtained from a theory for orthotropic curved plates in which deflections due to shear are taken into account. Results are given in the form of equations and curves."
Date:
January 1952
Creator:
Stein, Manuel & Mayers, J.
System:
The UNT Digital Library
Aerodynamic Characteristics of a Circular Cylinder at Mach Number 6.86 and Angles of Attack Up to 90 Degrees
"Pressure-distribution and force tests of a circular cylinder have been made in the Langley 11-inch hypersonic tunnel at a Mach number of 6.88, a Reynolds number of 129,000, and angles of attack up to 90 degrees. The results are compared with the hypersonic approximation of Grimminger, Williams, and Young and a simple modification of the Newtonian flow theory. An evaluation of the crossflow theory is made through comparison of present results with available crossflow Mach number drag coefficients" (p. 1).
Date:
January 1957
Creator:
Penland, Jim A.
System:
The UNT Digital Library