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Gust loads and operating airspeeds of one type of four-engine transport airplane on three routes from 1949 to 1953
Report presenting about 50,000 hours of V-G data obtained from one type of four-engine civil transport airplane operated over three different commercial airline routes of the United States from 1949 to 1953, which were analyzed to determine the magnitude and frequency of occurrence of gust loads and gusts. The frequency of occurrence of the gust loads and the gusts for the present operations is in general agreement with those from similar operations of other civil transports recently investigated.
Date:
November 1953
Creator:
Walker, Walter G.
System:
The UNT Digital Library
The Effect of Vertical Chine Strips on the Planing Characteristics of V-Shaped Prismatic Surfaces Having Angles of Dead Rise of 20 Degrees and 40 Degrees
Report presenting an investigation of the effect of vertical chine strips on the planing characteristics of two prismatic surfaces having angles of dead rise of 20 degrees and 40 degrees. Wetted lengths, resistance, and center-of-pressure location were determined at speed coefficients up to 25.0, load coefficients up to approximately 80.0, and trims up to 30 degrees.
Date:
November 1953
Creator:
Kapryan, Walter J. & Boyd, George M., Jr.
System:
The UNT Digital Library
Wind-tunnel investigation of six shielded total-pressure tubes at high angles of attack: Subsonic speeds
Report presenting a study of the effect of inclination of the air stream on the measured pressures of six shielded total-pressure tubes for a range of angles of attack. The tests were conducted over a range of Mach numbers. Results indicated that the shape of the venturi entry has a pronounced effect on the range of angles of attack over which the tubes remain insensitive to inclination of the air stream.
Date:
November 1951
Creator:
Russell, Walter R.; Gracey, William; Letko, William & Fournier, Paul G.
System:
The UNT Digital Library
An analysis of the errors in curve-fitting problems with an application to the calculation of stability parameters from flight data
From Introduction: "It is shown in the body of this report that the solution to the error problem depends upon a more or less arbitrary definition, the only criterion as to the choice of the definition being the usefulness of the solution to which it leads. In this respect, it may be said of the method derived herein that it is not difficult to apply and appears to lead reasonable values of the errors."
Date:
November 1952
Creator:
Shinbrot, Marvin
System:
The UNT Digital Library
Torsion tests of aluminum-alloy stiffened circular cylinders
Second report in a series presenting torsion testing on aluminum-alloy stiffened circular cylinders. The cylinders were similar to those from the first test with the exception of the wall thickness. Results regarding the action before buckling, buckling of curved panels, tension-field action, and ultimate torsional strengths are provided.
Date:
November 1952
Creator:
Clark, J. W. & Moore, R. L.
System:
The UNT Digital Library
Effect of a Rapid Blade-Pitch Increase on the Thrust and Induced-Velocity Response of a Full-Scale Helicopter Rotor
From Summary: "A method has been proposed for predicting the effect of a rapid blade-pitch increase on the thrust and induced-velocity response of a helicopter rotor. General equations have been derived for the ensuing motion of the helicopter. These equations yield time histories of thrust, induced velocity, and helicopter vertical velocity for given rates of blade-pitch-angle changes and given rotor-angular-velocity time histories. The results of the method have been compared with experimental results obtained with a rotor mounted on the Langley helicopter test tower."
Date:
November 1953
Creator:
Carpenter, Paul J. & Fridovich, Bernard
System:
The UNT Digital Library
Theoretical calculations of the effects of finite sideslip at supersonic speeds on the span loading and rolling moment for families of thin sweptback tapered wings at an angle of attack
Report presenting some results obtained from a general investigation of the effects of sideslip on the aerodynamic characteristics of thin sweptback tapered wings with side edges parallel to the axis of wing symmetry. Span load distributions have been calculated for several families of wings sideslipping at an angle of attack.
Date:
November 1953
Creator:
Sherman, Windsor L. & Margolis, Kenneth
System:
The UNT Digital Library
Experimental Investigation of the Effects of Cooling on Friction and on Boundary-Layer Transition for Low-Speed Gas Flow at the Entry of a Tube
Note presenting an investigation of the effect of cooling on boundary-layer transition in the steady flow of air in the entrance of a smooth round tube. The primary purpose was to investigate the practical possibilities of delaying the transition point, and thus increasing the transition Reynolds number, by cooling the laminar boundary layer in a gas. The results indicate that the effect of cooling on transition is not likely to be significant in any normal internal flow.
Date:
November 1953
Creator:
Kline, Stephen J. & Shapiro, Ascher H.
System:
The UNT Digital Library
Low-speed drag of cylinders of various shapes
Report presenting an investigation to find the approximate variation of the drag coefficient with Reynolds number of several cylinders with different cross-sectional shapes. Data were obtained for circular cylinders, elliptical cylinders of two fineness ratios, rectangular and diamond cylinders of three fineness ratios, and two isosceles triangular cylinders.
Date:
November 1953
Creator:
Delany, Noel K. & Sorensen, Norman E.
System:
The UNT Digital Library
Experimental stress analysis of stiffened cylinders with cutouts: Pure torsion
Torsion tests were made on a cylindrical semimonocoque shell of circular cross section. The cylinder was first tested without a cutout, and then with a rectangular cutout which was successively enlarged through six sizes varying from 30 degrees to 130 degrees in circumference and from 1 to 2 bays in length. Strain measurements were made with resistance-type wire strain gages near the cutout on the stringers, the skin, and the rings for each size of cutout, and the stresses obtained are presented in tables. (author).
Date:
November 1953
Creator:
Schlechte, Floyd R. & Rosecrans, Richard
System:
The UNT Digital Library
Use of two-dimensional data in estimating loads on a 45 degree sweptback wing with slats and partial-span flaps
Report presenting a study of the application of two-dimensional data and span-loading theory for estimating the local loading characteristics on a swept wing with flaps. Estimated results are compared with results measured at large scale on a 45 degree sweptback wing of aspect ratio 6 with a 0.4-span double-slotted flap. Results regarding chordwise loading, spanwise loading, and local lift curves are provided.
Date:
November 1953
Creator:
Hunton, Lynn W. & James, Harry A.
System:
The UNT Digital Library
Summary of revised gust-velocity data obtained from V-G records taken on civil transport airplanes from 1933 to 1950
Report presenting gust-velocity data obtained by reevaluating the normal accelerations and airspeeds from V-G records taken on civil transport airplanes from 1933 to 1950. The reevaluation was made on the basis of a derived gust velocity, which is related to the effective gust velocity by a conversion factor that is a function of the type of airplane and operating altitude.
Date:
November 1953
Creator:
Walker, Walter G.
System:
The UNT Digital Library
High-Frequency Pressure Indicators for Aerodynamic Problems
Note presenting three different types of pressure indicators developed at the Massachusetts Institute of Technology. Each has a unique feature, but all are designed with an attempt to combine both high-frequency response and high resolving power into one instrument. Five different types of pressure receivers were tested, including the cylinder, flat-diaphragm, spherical-diaphragm, catenary-diaphragm, and stretched-diaphragm, or membrane types. The pressure indicators are dynamically calibrated by means of a shock tube.
Date:
November 1953
Creator:
Li, Y. T.
System:
The UNT Digital Library
Application of Silver Chloride in Investigations of Elasto-Plastic States of Stress
Note presenting a description of the use of silver chloride as a material for photoelastic stress analysis, which offers the possibilities of studying both elastic and plastic states of stress in a crystalline metallike material on either a microscale or macroscale. In order to use it, however, it is necessary to relate the stress state quantitatively with the observed relative retardation and extinction angle.
Date:
November 1953
Creator:
Goodman, L. E. & Sutherland, J. G.
System:
The UNT Digital Library
Evaluation of High-Angle Attack Aerodynamic-Derivative Data and Stall-Flutter Prediction Techniques
Note presenting two approaches to the problem of stall flutter. First, the aerodynamic reactions on wings oscillating harmonically in pitch and translation in the stall range have been measured, evaluated, and correlated where possible with available published data, with the purpose of providing empirical information where no aerodynamic theory exists. Second, the results of numerous experimental observations of stall flutter have been reviewed and the various known attempts at its prediction have been examined, compared, and extended.
Date:
November 1951
Creator:
Halfman, Robert L.; Johnson, H. C. & Haley, S. M.
System:
The UNT Digital Library
Experimental Investigation of the Low-Speed Static and Yawing Stability Characteristics of a 45 Degrees Sweptback High-Wing Configuration with Various Twin Vertical Wing Fins
Note presenting an investigation to determine the low-speed static stability and yawing stability characteristics of a 45 degree sweptback high-wing, low-horizontal-tail configuration with various twin vertical wing fins. Generally, the static longitudinal stability characteristics were not affected by either upper-surface or lower-surface wing fins. Results regarding presentation of the data and general remarks, static stability characteristics, and yawing stability characteristics are provided.
Date:
November 1951
Creator:
Goodman, Alex & Wolhart, Walter D.
System:
The UNT Digital Library
An Analysis of Normal Accelerations and Airspeeds of One Type of Twin-Engine Transport Airplane in Commercial Operations Over a Northern Transcontinental Route
Note presenting normal-acceleration and airspeed data obtained for one type of twin-engine transport airplane in commercial operations in order to determine the gust and gust-load experiences of the airplane. Results regarding acceleration experience, gust experience, seasonal effects, and effect of special operating restriction are provided.
Date:
November 1952
Creator:
Steiner, Roy
System:
The UNT Digital Library
Flow surfaces in rotating axial-flow passages
Report presenting an investigation of three-dimensional, incompressible, nonviscous, absolute irrotational fluid motion is determined for flow through rotating axial-flow passages bounded by straight blades of finite spacing and infinite axial length lying on meridional planes. Solutions are obtained for five passages with varying blade spacing and hub-tip ratio. The results are presented in such a manner as to apply for all ratios of axial velocity to passage tip speed.
Date:
November 1952
Creator:
Stanitz, John D. & Ellis, Gaylord O.
System:
The UNT Digital Library
The Application of Planing Characteristics to the Calculation of the Water-Landing Loads and Motions of Seaplanes of Arbitrary Constant Cross Section
Note presenting the general equations governing the fixed-trim water landing of a straight-keel seaplane with a hull of arbitrary constant cross section in such a form that the landing motions and loads are expressed in terms of the steady planing characteristics of the seaplane.
Date:
November 1952
Creator:
Smiley, Robert F.
System:
The UNT Digital Library
Buckling of Low Arches or Curved Beams of Small Curvature
A general solution, based on the classical buckling criterion, is given for the problem of buckling of low arches under a lateral loading acting toward the center of curvature. For a sinusoidal arch under sinusoidal loading, the critical load can be expressed exactly as a simple function of the beam dimension parameters. For other arch shapes and load distributions, approximate values of the critical load can be obtained by summing a few terms of a rapidly converging Fourier series.
Date:
November 1952
Creator:
Fung, Y. C. & Kaplan, A.
System:
The UNT Digital Library
Experimental Investigation of Eccentricity Ratio, Friction, and Oil Flow of Short Journal Bearings
An experimental investigation was conducted to obtain performance data on bearings of length-diameter ratios of 1, 1/2, and 1/4 for comparison with theoretical curves. A 1.375-inch-diameter bearing was tested at speeds up to 6000 rpm and with unit loads from 0 to 900 pounds per square inch. Experimental data for eccentricity ratio and friction followed single lines when plotted against a theoretically derived capacity number, which is equal to Sommerfeld number times the square of the length-diameter ratio.
Date:
November 1952
Creator:
DuBois, G. B. & Ocvirk, F. W.
System:
The UNT Digital Library
Corrections for Drag, Lift, and Moment of an Axially Symmetrical Body Placed in a Supersonic Tunnel Having a Two-Dimensional Pressure Gradient
Note presenting corrections for drag, lift, and moment that are derived for an axially symmetrical body placed in the test section of a supersonic tunnel on the assumption that the test section is characterized by a two-dimensional pressure field originating from construction flaws. Assuming irrotational conditions, the velocity potential of the flow around the body is expanded in a threefold manner: in powers of the thickness parameter of the body, in powers of a parameter characterized the inhomogeneity of the basic flow field, and as a Fourier series in the azimuth around the body axis.
Date:
November 1952
Creator:
Kolodner, I. J.; Reiche, F. & Ludloff, H. F.
System:
The UNT Digital Library
Acoustic analysis of ram-jet buzz
From Introduction: "The surging of a system containing a centrifugal- or axial-flow compressor (e.g., refs. 1 to 4) is an example of self-sustained oscillation. Inlets designed for supersonic jet engines also have been observed to induce oscillations (e.g., refs. 5 to 11) which are usually referred to as "buzz." The origin of buzz in ram-jet engines is the subject of the present report."
Date:
November 1955
Creator:
Mirels, Harold
System:
The UNT Digital Library
Experimental investigation of blade flutter in an annular cascade
Report presenting an investigation of the stall operation of an annular cascade under varied conditions of geometry and air flow. Controlled variables included angle of attack, blade chord and spacing, number of blades in the cascade, and air velocity. Results regarding stalling flutter, vibratory stress, aerodynamic damping characteristics, nature of vibrations, and presence of rotating stall are provided.
Date:
November 1955
Creator:
Rowe, J. R. & Mendelson, A.
System:
The UNT Digital Library