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Experiments With an Airfoil Model on Which the Boundary Layers Are Controlled Without the Use of Supplementary Equipment
This report describes test made in the Variable Density Wind Tunnel of the NACA to determine the possibility of controlling the boundary layer on the upper surface of an airfoil by use of the low pressure existing near the leading edge. The low pressure was used to induce flow through slots in the upper surface of the wing. The tests showed that the angle of attack for maximum lift was increased at the expense of a reduction in the maximum lift coefficient and an increase in the drag coefficient.
Date:
April 1931
Creator:
Abbott, Ira H.
System:
The UNT Digital Library
Determination of vortex paths by series expansion technique with application to cruciform wings
Report presenting a series method of determining two-dimensional vortex paths is considered and applied to the computation of vortex positions behind a slender equal-span cruciform wing at any angle of bank as a function of the distance behind the trailing edge.
Date:
April 1956
Creator:
Alksne, Alberta Y.
System:
The UNT Digital Library
Turbulent Shearing Stress in the Boundary Layer of Yawed Flat Plates
Note presenting hot-wire anemometer measurements of the turbulent shearing stress in a turbulent boundary layer on a yawed flat plate. The measured velocity profiles are used to calculate the shear distribution and the result is compared with the result of experimental shear measurements.
Date:
April 1958
Creator:
Ashkenas, Harry
System:
The UNT Digital Library
Investigation of the Turbulent Boundary Layer on a Yawed Flat Plate
Note presenting the problem of the effect of yaw on the turbulent boundary layer and skin friction of infinite cylinders, which is reviewed and compared with the case of laminar flow. The conclusion indicates that present understanding of the mechanism of turbulent shear does not permit exhaustion of two-dimensional data even to this elementary case of three-dimensional flow. Results regarding pressure distributions, two-dimensionality and flow direction, velocity profiles, virtual origin, virtual origin for yawed plates, boundary-layer growth, and the results obtained by Young and Booth are provided.
Date:
April 1955
Creator:
Ashkenas, Harry & Riddell, Frederick R.
System:
The UNT Digital Library
Coefficient of friction and damage to contact area during the early stages of fretting 2: steel, iron, iron oxide, and glass combinations
Report presenting experiments to study the start of fretting and cause of damage during the early stages of fretting of steel-steel combinations at a frequency 5 cycles per minute, an amplitude of 0.006 inch, a load of 150 grams, in air with relative humidity of less than 10 percent. Pure iron, glass, and iron oxide powder compacts were used in supplementary experiments.
Date:
April 1954
Creator:
Bailey, John M. & Godfrey, Douglas
System:
The UNT Digital Library
Spinning Characteristics of Wings 2: Rectangular Clark Y Biplane Cellule: 25 Percent Stagger; 0 Degree Decalage; Gap/Chord 1.0
General methods of theoretical analysis of airplane spinning characteristics have been available for some time. Some of these methods of analysis might be used by designers to predict the spinning characteristics of proposed airplane designs if the necessary aerodynamic data were known. The present investigation, to determine the spinning characteristics of wings, is planned to include variations in airfoil sections, plan forms, and tip shapes of monoplane wings and variations in stagger, gap, and decalage for biplane cellules.
Date:
April 1935
Creator:
Bamber, M. J.
System:
The UNT Digital Library
Wind-Tunnel Tests of Several Forms of Fixed Wing Slot in Combination With a Slotted Flap on an N.A.C.A. 23012 Airfoil
Note presenting tests of several forms of fixed wing slot in a large-chord NACA 23012 airfoil in the closed-throat 7- by 10-foot wind tunnel. The airfoil extended completely across the test section so that two-dimensional flow was approximated. The data are presented in the form of tables of important aerodynamic characteristics for each slot tested and as curves of section lift, profile-drag, and pitching-moment coefficients.
Date:
April 1939
Creator:
Bamber, M. J.
System:
The UNT Digital Library
Wind-tunnel investigation of effect of yaw on lateral-stability characteristics 1: four N.A.C.A. 23012 wings of various plan forms with and without dihedral
Four N.A.C.A. 23012 wings were tested at several angles of yaw in the N.A.C.A. 7- by 10-foot wind tunnel. All the wings have rounded tips and, in plan form, one is rectangular and the others are tapered 3:1 with various amounts of sweep. Each wing was tested with two amounts of dihedral and with partial-span split flaps. The coefficients of lift, drag, and pitching moment are given for all the models at zero yaw. The coefficients of rolling moment, yawing moment, and side force are given for the rectangular wing at all values of yaw tested. The rate of change in the coefficients with angle of yaw is given in convenient form for stability calculations.
Date:
April 1939
Creator:
Bamber, M. J. & House, R. O.
System:
The UNT Digital Library
Effect of an Interface on Transient Temperature Distribution in Composite Aircraft Joints
Note presenting testing of geometrically related structural joints representing typical skin-stringer cross sections under radiant heating to simulate the effects of aerodynamic heating. The presence of an interface was found to have a significant effect on the temperature distribution in all geometries tested and thus must be considered in temperature calculations. Interface conductance values were computed for each of the 15 fabricated specimens.
Date:
April 1957
Creator:
Barzelay, Martin E. & Holloway, George F.
System:
The UNT Digital Library
A Mathematical Theory of Plasticity Based on the Concept of Slip
Note presenting a theory of plasticity based on the concept of slip as proposed for the relationship between stress and strain for initially isotropic materials in the strain-hardening range. The theory is an extension to polyaxial stress conditions of the conventional uniaxial stress-strain relation, and time-dependent effects, such as creep and stress relaxation, are not considered.
Date:
April 1949
Creator:
Batdorf, S. B. & Budiansky, Bernard
System:
The UNT Digital Library
Variation of Hydrodynamic Impact Loads With Flight-Path Angle for a Prismatic Float at 0 and -3 Degree Trim and With a 22 1/2 Degree Angle of Dead Rise
Report presenting testing on a prismatic float model to determine the relationship between the vertical landing acceleration and flight-path angle for seaplanes landing in smooth water. Results regarding the maximum load factor, maximum impact normal acceleration, pressures, and stability of landings are provided.
Date:
April 1947
Creator:
Batterson, Sidney A.
System:
The UNT Digital Library
Determination of the Value of Wood for Structural Purposes
Note presenting an investigation of the value of wood for structural parts subject to stress. An exploration of several different types of wood is provided, including the coefficeint of elongation in bending, tensile strength, compression strength, and energy required for fracture is provided.
Date:
April 1923
Creator:
Baumann, Richard
System:
The UNT Digital Library
Structural hinge-moment increments caused by hinge-axis distortion
Report presenting an investigation of elevators with three hinges to evaluate the structural hinge-moment increments resulting from changing the elevator angle when the hinge axis is distorted under load. The analytical results are compared to test data obtained for a full-scale semispan fighter-type horizontal tail surface in the 16-foot high-speed tunnel.
Date:
April 1946
Creator:
Becker, John V. & Cooper, Morton
System:
The UNT Digital Library
Effect of Partial Wing Lift in Seaplane Landing Impact
Note presenting a solution for the motion of a prismatic float of infinite length that is dropped vertically into the water at zero trim. A lift force, simulating seaplane wing lift, is assumed to act on the float and to remain constant during the impact period.
Date:
April 1948
Creator:
Benscoter, Stanley U.
System:
The UNT Digital Library
Charts for the Rapid Calculation of the Work Required to Compress Dry Air
Report presenting a study of accurate values of the specific heat for dry air applied to the calculation of work required to compress dry air. Two charts are provided that allow the work of compression to be determined from the initial temperature, overall pressure ratio, and either the compression exponent or adiabatic efficiency of the compressor.
Date:
April 1946
Creator:
Benser, William A.; Wilcox, Ward W. & Voit, Charles H.
System:
The UNT Digital Library
Effects of leading-edge radius and maximum thickness-chord ratio on the variation with Mach number of the aerodynamic characteristics of several thin NACA airfoil sections
Report presenting a wind-tunnel investigation to determine the effects of leading-edge radius and maximum thickness-chord ratio on the variation with Mach number of the aerodynamic characteristics of several thin symmetrical NACA 4-digit-series airfoil sections. The variations with Mach number of the lift, drag, and pitching moment for a 4-percent-chord-thick airfoil section are not significantly affected by a change of leading-edge radius from 0.18 to 0.53 percent of the chord.
Date:
April 14, 1954
Creator:
Berggren, Robert E. & Graham, Donald J.
System:
The UNT Digital Library
On the Continuation of a Potential Gas Flow Across the Sonic Line
"Simple, sufficient conditions are given under which a two-dimensional steady compressible flow can be continued across the line of Mach number 1 as a continuous supersonic flow. Methods for the actual computation of the flow are described. The problem is of importance in the theory of transonic flows past airfoils" (p. 1).
Date:
April 1950
Creator:
Bers, Lipman
System:
The UNT Digital Library
Velocity Distribution on Wing Sections of Arbitrary Shape in Compressible Potential Flow 1: Circulatory Flows Obeying the Simplified Density-Speed Relation
"As a first step toward the computation of the velocity distribution along a wing profile of arbitrary shape in a compressible fluid, the circulation-free flow around a symmetrical profile is treated under the assumption of the simplified density-speed relation due to Tchaplygin, Karman, and Tsien. The velocity distribution problem is reduced to a non-linear integral equation which is solved by a fairly rapidly convergent iteration method. Numerical examples are given" (p. 1).
Date:
April 1946
Creator:
Bers, Lipman
System:
The UNT Digital Library
Analysis of an induction blowdown supersonic tunnel
From Introduction: "In the present paper, general ejector equations (see reference 4 or 5) and certain assumptions with regard to flow conditions and pressure losses have been utilized to calculate the running times of induction blowdown supersonic tunnels operating in the mentioned Mach number range."
Date:
April 1950
Creator:
Bidwell, Jerold M.
System:
The UNT Digital Library
An Experimental Investigation at Low Speeds of the Effects of Lip Shape on the Drag and Pressure Recovery of a Nose Inlet in a Body of Revolution
Report presenting wind-tunnel tests of a body of revolution with a circular nose inlet conducted at low speeds to ascertain some of the effects of inlet lip bluntness and profile on diffuser performance and body drag. Testing occurred at free-stream Mach numbers up to 0.330 with inlet flows from zero to choking and a steady 0 degree angle of attack and angle of yaw. Results regarding the internal-flow studies with the strut-mounted model and drag and surface-pressure studies with the sting-supported model are provided.
Date:
April 1954
Creator:
Blackaby, James R. & Watson, Earl C.
System:
The UNT Digital Library
An Application of Statistical Data in the Development of Gust-Load Criterions
"In conjunction with assumptions concerning the proportion of time spent at various speeds, statistical gust data were used to determine gust load factors that could be exceeded a given number of times during the operational life of an airplane. The results indicated that present gust load factors might be considerably lowered in certain cases with a consequent decrease in structural weight. Modification of the present criterion, however, must await the accumulation of data not presently available" (p. 1).
Date:
April 1947
Creator:
Bland, Reginald B. & Reisert, T. D.
System:
The UNT Digital Library
Axial-flow fan and compressor blade design data on 52.5 degrees stagger and further verification of cascade data by rotor tests
From Summary: "Previous tests of blower-blade sections have been extended by a series of tests at 52.5 degrees stagger. The results of these tests have been combined with the earlier test results and are presented in new blade design charts which supersede those previously presented. An investigation in a test blower over a range of stagger from 44 degrees to 65 degrees has shown that for blades at a solidity of 1.0, the two-dimensional cascade data predict the turning angle to within 1/2 degrees."
Date:
April 1947
Creator:
Bogdonoff, Seymour M. & Hess, Eugene E.
System:
The UNT Digital Library
Optimum controllers for linear closed-loop systems
Report presenting an analysis for optimum controllers of general, linear, time-invariant multiloop systems. General representations of controller characteristics, stable process characteristics, and error relations are used. General solutions are presented for four special cases.
Date:
April 1953
Creator:
Boksenbom, Aaron S.; Novik, David & Heppler, Herbert
System:
The UNT Digital Library
A numerical approach to the instability problem of monocoque cylinders
Report presenting two closely related methods which employ operations tables that have been developed and used in the calculation of buckling load of a monocoque cylinder subjected to pure bending. The buckling loads of three cylinders with very different characteristics were calculated using the methods.
Date:
April 1951
Creator:
Boley, Bruno A.; Kempner, Joseph & Mayers, J.
System:
The UNT Digital Library