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Considerations of the Total Drag of Supersonic Airfoil Sections
The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.
Date:
July 1947
Creator:
Ivey, H. Reese & Klunker, E. Bernard
System:
The UNT Digital Library
Aerodynamic Investigation of a Cup Anemometer
Results of an investigation wherein the change of the normal force coefficient with Reynolds Number was obtained statically for a 15.5-centimeter hemispherical cup.
Date:
July 1934
Creator:
Hubbard, John D. & Brescoll, George P.
System:
The UNT Digital Library
Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Oxygen-Nitrogen System at Temperatures From 2000° to 5000° Degrees K
Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.
Date:
July 1948
Creator:
Huff, Vearl N. & Calvert, Clyde S.
System:
The UNT Digital Library
Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel
"The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces" (p. 1).
Date:
July 1941
Creator:
Greenberg, Harry
System:
The UNT Digital Library
Principal Effects of Axial Load on Moment-Distribution Analysis of Rigid Structures
"This thesis presents the method of moment distribution modified to include the effect of axial load upon the bending moments. This modification makes it possible to analyze accurately complex structures, such as rigid fuselage trusses, that heretofore had to be analyzed by approximate formulas and empirical rules. The method is simple enough to be practicable even for complex structures, and it gives a means of analysis for continuous beams that is simpler than the extended three-moment equation now in common use" (p. 1).
Date:
July 1935
Creator:
James, Benjamin Wylie
System:
The UNT Digital Library
Low tip Mach number stall characteristics and high tip Mach number compressibility effects on a helicopter rotor having an NACA 0009 tip airfoil section
Report presenting an investigation conducted on the helicopter test tower to determine experimentally the low tip Mach number stall and high tip Mach number drag divergence characteristics of a helicopter rotor with an NACA 0009 tip airfoil section. Results regarding rotor hovering performance, rotor-blade pitching moments, rotor profile-drag torque, and a comparison with two-dimensional drag-divergence data are provided.
Date:
July 1958
Creator:
Powell, Robert D., Jr. & Carpenter, Paul J.
System:
The UNT Digital Library
Wind-tunnel investigation of the high-subsonic static longitudinal stability characteristics of several wing-body configurations designed for high lift-drag ratios at a Mach number of 1.4
Report presenting testing in the high-speed 7- by 10-foot tunnel to investigate the high-subsonic static longitudinal stability characteristics and lift-drag ratios of several wing-body models designed to provide high lift-drag ratios at Mach number 1.4. The basic configuration had a thin highly swept wing of aspect ratio 2.91 with NACA 65-A series airfoil sections. Results regarding longitudinal stability, lift, drag, and lift-drag ratio are provided.
Date:
July 1958
Creator:
Fournier, Paul G.
System:
The UNT Digital Library
Effects of Thermal Relaxation and Specific-Heat Changes on Measurements With a Pneumatic-Probe Pyrometer
"Equations are derived which evaluate the effects of thermal vibrational relaxation and specific-heat changes on pneumatic-probe pyrometer measurements in the region 1000 to 3000 degrees K and Mach numbers between 0.3 and 2.0. Examples are given for typical probes in two combustion mixtures" (p. 1).
Date:
July 1957
Creator:
Kuhns, P. W.
System:
The UNT Digital Library
Low-speed experimental determination of the effects of leading-edge radius and profile thickness on static and oscillatory lateral stability derivatives for a delta wing with 60 degrees of leading-edge sweep
Report presenting an investigation to determine the effects of leading-edge radius and profile thickness on the oscillatory lateral stability derivatives for a series of delta wings with 60 degrees of leading-edge sweep. The wings were oscillated in yaw about their vertical axes. Results indicated that there were noticeable decreases in all the derivatives due to increase in leading-edge radius at angles of attack above approximately 12 degrees.
Date:
July 1958
Creator:
Fletcher, Herman S.
System:
The UNT Digital Library
Wind-tunnel investigation at low speeds of flight characteristics of a sweptback-wing jet-transport airplane model equipped with an external-flow jet-augmented slotted flap
Report presenting a wind-tunnel investigation at low speeds to determine the flight characteristics of a model of a sweptback-wing jet-transport airplane equipped with an external-flow jet-augmented slotted flap. Results regarding the longitudinal stability characteristics, longitudinal control characteristics, lateral stability characteristics, and lateral control characteristics are provided.
Date:
July 1958
Creator:
Johnson, Joseph L., Jr.
System:
The UNT Digital Library
Preliminary investigation of propane combustion in a 3-inch-diameter duct of inlet-air temperatures of 1400 to 1600 F
Report presenting a determination of ignition delays and combustion efficiencies for propane injected into a heated airstream. Two types of flames were observed for multipoint fuel injectors: a diffusion flame that stabilized at the injector orifices and an ignition-stabilized flame that formed a flame front downstream of the fuel injector. Results regarding combustion of injector-stabilized flames and combustion of ignition-stabilized flames are provided.
Date:
July 1957
Creator:
Lezberg, Erwin A.
System:
The UNT Digital Library
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" (p. 1).
Date:
July 1942
Creator:
Levy, Samuel & Greenman, Samuel
System:
The UNT Digital Library
Effects of airplane flexibility on wing bending strains in rough air
"Some results on the effects of wing flexibility on wing bending strains as determined from flight tests of a Boeing B-29 and a Boeing B-47A airplane in rough air are presented. Results from an analytical study of the flexibility effects on the B-29 wing strains are compared with the experimental results. Both the experimental and calculated results are presented as frequency-response functions of the bending strains at various spanwise wing stations to gust disturbances. In addition, some indirect evidence of the effect of spanwise variations in turbulence on the response of the B-47A airplane is presented" (p. 1).
Date:
July 1957
Creator:
Coleman, Thomas L.; Press, Harry & Shufflebarger, C. C.
System:
The UNT Digital Library
Some Investigations of the General Instability of Stiffened Metal Cylinders 1: Review of Theory and Bibliography
This is the first of a series of reports covering an investigation of the general instability problem. This report consists of earlier reports along with the results of the current studies in the form of a series of reports covering the entire investigation.
Date:
July 1943
Creator:
unknown
System:
The UNT Digital Library
Vibration survey of four representative types of air-cooled turbine blades
Report presenting an investigation conducted in a turbojet engine mounted in a sea-level test stand to determine the vibrational characteristics of four representative types of air-cooled turbine blades.Two were standard-span blades and two were long-span blades for high mass-flow turbines. Results regarding the coolant-flow rate, vibratory stresses, vibrational characteristics, and failures are provided.
Date:
July 1958
Creator:
Calvert, Howard F. & Smith, Gordon T.
System:
The UNT Digital Library
Studies of structural failure due to acoustic loading
A discussion of the acoustic fatigue problem of aircraft structures along with data pertaining to the acoustic inputs from some power plants in common use. Comparisons are given for results of fatigue tests of flat panels and cantilever beams exposed to random- and discrete-type inputs. Both the stress level of the test and type of model are significant, so no generalizations can be made at this time.
Date:
July 1957
Creator:
Hess, Robert W.; Fralich, Robert W. & Hubbard, Harvey H.
System:
The UNT Digital Library
Ground Effects on the Longitudinal Characteristics of Two Models With Wings Having Low Aspect Ratio and Pointed Tips
Wind-tunnel tests were conducted to determine the ground effects on a tailless model with a wing of aspect ratio 2 and infinite taper, and on a tailed model with a triangular wing of aspect ratio 3, with flaps. Control-surface hinge moments were measured on the tailless model. The results are compared with the predictions of the theory of Tani, et al.
Date:
July 1957
Creator:
Buell, Donald A. & Tinling, Bruce E.
System:
The UNT Digital Library
Propellant vaporization as a criterion for rocket engine design; Calculations of chamber length to vaporize a single n-heptane drop
Report presenting an analysis based on droplet-evaporation theory, which shows that for a given combustor length, the percent of fuel mass vaporized can be increased by decreasing the fuel-drop size and initial drop velocity, or by increasing chamber pressure, final gas velocity, and initial fuel temperature. The results were correlated to give a single curve of percent of fuel evaporated as a function of the chamber length and the factors involving the parameters.
Date:
July 1957
Creator:
Priem, Richard J.
System:
The UNT Digital Library
Internal characteristics and performance of an aerodynamically controlled, variable-discharge convergent nozzle
Report presenting a study in which the effective flow area of a convergent exhaust nozzle was reduced by injecting a high-pressure secondary jet into the nozzle near the exit. Analytical expressions relating the performance with significant design and operating variables were developed. Some of the configurations, altered to operate as jet deflectors, produced significant values of side force but also operated at reduced effective flow area.
Date:
July 1958
Creator:
McArdle, Jack G.
System:
The UNT Digital Library
Effect of favorable pressure gradients on transition for several bodies of revolution at Mach 3.12
Report presenting experimental results relating to the effect of pressure gradient on the location of transition for several constant-pressure-gradient models an two power-profile models. Results regarding the local flow conditions, recovery-factor distributions, effect of unit Reynolds number, and effect of pressure gradient are provided.
Date:
July 1958
Creator:
Jack, John R.
System:
The UNT Digital Library
Experimental Investigation of Attenuation of Strong Shock Waves in a Shock Tube With Hydrogen and Helium as Driver Gases
Note presenting an experimental investigation of the attenuation of strong shock waves in air in a shock tube. Time-history measurements were made of the static pressure at several stations in the wall of the tube. Hydrogen and helium were used as driver gases. A helium-driven shock wave was found to decay only about one-half as rapidly as a hydrogen-driven shock wave.
Date:
July 1957
Creator:
Jones, Jim J.
System:
The UNT Digital Library
Dynamic stability of vehicles traversing ascending or descending paths through the atmosphere
From Summary: "An analysis is given of the oscillatory motions of vehicles which traverse ascending and descending paths through the atmosphere at high speed. The specific case of a skip path is examined in detail, and this leads to a form of solution for the oscillatory motion which should recur over any trajectory. The distinguishing feature of this form is the appearance of the Bessel rather than the trigonometric function as the characteristic mode of oscillation."
Date:
July 1958
Creator:
Tobak, Murray & Allen, H. Julian
System:
The UNT Digital Library
An evaluation of the effects of flexibility on wing strains in rough air for a large swept-wing airplane by means of experimentally determined frequency-response functions with an assessment of random-process techniques employed
Report presenting power spectral methods of analysis as applied to flight test measurements of the strain responses of a large swept-wing bomber airplane in rough air in order to determine the effects of airplane in rough air in order to determine the effects of airplane structural dynamics on the strain responses.
Date:
July 1958
Creator:
Coleman, Thomas L.; Press, Harry & Meadows, May T.
System:
The UNT Digital Library
Local Instability of the Elements of a Truss-Core Sandwich Plate
The charts presented give the compressive buckling coefficients for a single-truss-core and a double-truss-core sandwich plate. These charts cover a wide range of sandwich proportions and may be used for sandwiches with unequal faces. They apply to inplane compressive loads acting parallel or perpendicular to the core direction or for various combinations of these loads. (author).
Date:
July 1958
Creator:
Anderson, Melvin S.
System:
The UNT Digital Library