Search Results

open access

An analysis of the stability and ultimate compressive strength of short sheet-stringer panels with special reference to the influence of the riveted connection between sheet and stringer

Description: A method of strength analysis of short sheet-stringer panels subjected to compression is presented which takes into account the effect that the riveted attachments between the plate and the stiffeners have on the strength of panels. An analysis of experimental data shows that panel strength is highly influenced by rivet pitch, diameter, and location and that the degree of influence for a given riveting depends on the panel configuration and panel material.
Date: 1956
Creator: Semonian, Joseph W. & Peterson, James P.
open access

Average Properties of Compressible Laminar Boundary Layer on Flat Plate With Unsteady Flight Velocity

Description: The time-average characteristics of boundary layers over a flat plate in nearly quasi-steady flow are determined. The plate may be either insulated or isothermal. The time averages are found without specifying the plate velocity explicitly except that it is positive and has an average value.
Date: September 5, 1956
Creator: Moore, Franklin K. & Ostrach, Simon
open access

Comparison of several methods for obtaining the time response of linear systems to either a unit impulse or arbitrary input from frequency-response data

Description: From Summary: "Several methods of obtaining the time response of Linear systems to either a unit impulse or an arbitrary input from frequency-response data are described and compared. Comparisons indicate that all the methods give good accuracy when applied to a second-order system; the main difference is the required computing time. The methods generally classified as inverse Laplace transform methods were found to be most effective in determining the response to a unit impulse from frequency-… more
Date: March 16, 1956
Creator: Donegan, James J. & Huss, Carl R.
open access

Correlation, Evaluation, and Extension of Linearized Theories for Tire Motion and Wheel Shimmy

Description: "An evaluation is made of the existing theories of a linearized tire motion and wheel shimmy. It is demonstrated that most of the previously published theories represent varying degrees of approximation to a summary theory developed in this report which is a minor modification of the basic theory of Von Schlippe and Dietrich. In most cases where strong differences exist between the previously published theories and summary theory, the previously published theories are shown to possess certain d… more
Date: January 13, 1956
Creator: Smiley, Robert F.
open access

Determination of vortex paths by series expansion technique with application to cruciform wings

Description: 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. Calculated paths are shown for four bank angles. For a bank angle of 45 degrees comparison is made with the results of a closed expression given in NACA-TN-2605. For other bank angles water-tank experiments provide qualitative comparison. Satisfactory ag… more
Date: February 8, 1956
Creator: Alksne, Alberta Y.
open access

Ditching investigations of dynamic models and effects of design parameters on ditching characteristics

Description: From Summary: "Data from ditching investigations conducted at the Langley Aeronautical Laboratory with dynamic scale models of various airplanes are presented in the form of tables. The effects of design parameters on the ditching characteristics of airplanes, based on scale-model investigations and on reports of full-scale ditchings, are discussed. Various ditching aids are also discussed as a means of improving ditching behavior."
Date: November 16, 1956
Creator: Fisher, Lloyd J. & Hoffman, Edward L.
open access

Effect of chord size on weight and cooling characteristics of air-cooled turbine blades

Description: An analysis has been made to determine the effect of chord size on the weight and cooling characteristics of shell-supported, air-cooled gas-turbine blades. In uncooled turbines with solid blades, the general practice has been to design turbines with high aspect ratio (small blade chord) to achieve substantial turbine weight reduction. With air-cooled blades, this study shows that turbine blade weight is affected to a much smaller degree by the size of the blade chord.
Date: November 13, 1956
Creator: Esgar, Jack B.; Schum, Eugene F. & Curren, Arthur N.
open access

An evaluation of four experimental methods for measuring mean properties of a supersonic turbulent boundary layer

Description: From Summary: "Surveys were made through a turbulent boundary layer on a flat plate by means of a pitot probe, an x-ray densitometer, and hot-wire and cold-wire probes. Results from these surveys were analyzed to determine (a) the reliability of the basic data and hence the methods by which they were obtained, and (b) how well the actual distributions of properties in the boundary layer compare with those commonly assumed in semiempirical and theoretical analyses. All surveys were made at the s… more
Date: April 19, 1956
Creator: Nothwang, George J.
open access

Experimental determination of effects of frequency and amplitude on the lateral stability derivatives for a delta, a swept, and unswept wing oscillating in yaw

Description: "Three wing models were oscillated in yaw about their vertical axes to determine the effects of systematic variations of frequency and amplitude of oscillation on the in-phase and out-of-phase combination lateral stability derivatives resulting from this motion. The tests were made at low speeds for a 60 degree delta wing, a 45 degree swept wing, and an unswept wing; the swept and unswept wings had aspect ratios of 4. The results indicate that large changes in the magnitude of the stability der… more
Date: January 6, 1956
Creator: Fisher, Lewis R.
open access

An experimental investigation of sting-support effects on drag and a comparison with jet effects at transonic speeds

Description: Various dummy stings were tested on the rear of a related series of afterbody shapes for Mach numbers from 0.80 to 1.10 and Reynolds numbers based on body length from 15.0 x 16 to the 6th power to 17.4 x 10 to the 6th power. A method is presented whereby approximate sting interference corrections can be made to models having afterbody shapes and sting supports similar to those of these tests if the Reynolds numbers are of the same order of magnitude and a turbulent boundary layer exists at the … more
Date: June 4, 1956
Creator: Cahn, Maurice S.
open access

Exploratory investigation of boundary-layer transition on a hollow cylinder at a Mach number of 6.9

Description: Report presenting an investigation of the Reynolds number for transition on the outside of a hollow cylinder with heat transfer from the boundary layer to the wall at Mach number 6.9. At a given Mach number, it appears that the Reynolds number based on leading-edge thickness is an important parameter in comparisons of flat-plate transition data from various installations.
Date: February 9, 1956
Creator: Bertram, Mitchel H.
open access

Flight investigation of the effectiveness of an automatic aileron trim control device for personal airplanes

Description: "A flight investigation to determine the effectiveness of an automatic aileron trim control device installed in a personal airplane to augment the apparent spiral stability has been conducted. The device utilizes a rate-gyro sensing element in order to switch an on-off type of control that operates the ailerons at a fixed rate through control centering springs. An analytical study using phase-plane and analog-computer methods has been carried out to determine a desirable method of operation for… more
Date: January 4, 1956
Creator: Phillips, William H.; Kuehnel, Helmut A. & Whitten, James B.
open access

Induced Velocities Near a Lifting Rotor With Nonuniform Disk Loading

Description: A method is given for converting known uniformly loaded rotor induced velocities to correspond with arbitrary axisymmetric nonuniform disk load distributions. Numerical results for two specific distributions are given in chart form. Symmetry relations and relations between radial disk loading and wake velocities are developed. Experimental flow measurements are presented and compared with theory. Reasonable agreement is shown in the forward part of the flow when nonuniform loading is assumed, b… more
Date: April 1956
Creator: Heyson, Harry H. & Katzoff, S.
open access

Intensity, scale, and spectra of turbulence in mixing region of free subsonic jet

Description: Report presents the results of the measurements of intensity of turbulence, the longitudinal and lateral correlation coefficients, and the spectra of turbulence in a 3.5-inch-diameter free jet measured with hot-wire anemometers at exit Mach numbers from 0.2 to 0.7 and Reynolds numbers from 192,000 to 725,000.
Date: April 24, 1956
Creator: Laurence, James C.
open access

Investigation of separated flows in supersonic and subsonic streams with emphasis on the effect of transition

Description: Report presents the results of experimental and theoretical research conducted on flow separation associated with steps, bases, compression corners, curved surfaces, shock-wave boundary-layer reflections, and configurations producing leading-edge separation. Results were obtained from pressure-distribution measurements, shadowgraph observations, high-speed motion pictures, and oil-film studies. The maximum scope of measurement encompassed Mach numbers between 0.4 and 3.6, and length Reynolds nu… more
Date: November 29, 1956
Creator: Chapman, Dean R.; Kuehn, Donald M. & Larson, Howard K.
open access

Investigation of the aerodynamic characteristics of a model wing-propeller combination and of the wing and propeller separately at angles of attack up to 90 degrees

Description: This report presents the results of an investigation conducted in the Langley 300 mph 7- by 10-foot wind tunnel for the purpose of determining the aerodynamic characteristics of a model wing-propeller combination, and of the wing and propeller separately at angles of attack up to 90 degrees. The tests covered thrust coefficients corresponding to free-stream velocities from zero forward speed to the normal range of cruising speeds. The results indicate that increasing the thrust coefficient incr… more
Date: 1956
Creator: Kuhn, Richard E. & Draper, John W.
open access

Investigation of the Laminar Aerodynamic Heat-Transfer Characteristics of a Hemisphere-Cylinder in the Langley 11-inch Hypersonic Tunnel at a Mach Number of 6.8

Description: "A program to investigate the aerodynamic heat transfer of a nonisothermal hemisphere-cylinder has been conducted in the Langley 11-inch hypersonic tunnel at a Mach number of 6.8 and a Reynolds number from approximately 0.14 x 10(6) to 1.06 x 10(6) based on diameter and free-stream conditions. The experimental heat-transfer coefficients were slightly less over the whole body than those predicted by the theory of Stine and Wanlass (NACA technical note 3344) for an isothermal surface. For station… more
Date: March 21, 1956
Creator: Crawford, Davis H. & McCauley, William D.
open access

A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition

Description: From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer located at various chordwise stations for each position of the roughness. These observations indicated that when the roughness is sufficiently submerged in the boundary layer to provide a substantially linear variation of boundary-layer … more
Date: August 15, 1956
Creator: von Doenhoff, Albert E. & Horton, Elmer A.
open access

Measurement of aerodynamic forces for various mean angles of attack on an airfoil oscillating in pitch and on two finite-span wings oscillating in bending with emphasis on damping in the stall

Description: "The oscillating air forces on a two-dimensional wing oscillating in pitch about the midchord have been measured at various mean angles of attack and at Mach numbers of 0.35 and 0.7. The magnitudes of normal-force and pitching-moment coefficients were much higher at high angles of attack than at low angles of attack for some conditions. Large regions of negative damping in pitch were found, and it was shown that the effect of increasing the Mach number 0.35 to 0.7 was to decrease the initial an… more
Date: January 21, 1956
Creator: Rainey, A. Gerald
open access

Measurement of Static Pressure on Aircraft

Description: "Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented" (p. 645).
Date: December 17, 1956
Creator: Gracey, William
open access

Method for calculating the aerodynamic loading on an oscillating finite wing in subsonic and sonic flow

Description: A method is presented for calculating the loading on a finite wing oscillating in subsonic or sonic flow. The method is applicable to any plan form and may be used for determining the loading on deformed wings. The procedure is approximate and requires numerical integration over the wing surface.
Date: March 14, 1956
Creator: Runyan, Harry L. & Woolston, Donald S.
open access

Methods for obtaining desired helicopter stability characteristics and procedures for stability predictions

Description: Part I of this report presents a brief review of methods available to the helicopter designer for obtaining desired stability characteristics by modifications to the airframe design. The discussion is based on modifications made during the establishment of flying-qualities criteria and includes sample results of theoretical studies of additional methods. The conclusion is reached that it is now feasible to utilize combinations of methods whereby stability-parameter values are realized which in … more
Date: November 30, 1956
Creator: Gustafson, F. B. & Tapscott, Robert J.
open access

Minimum wave drag for arbitrary arrangements of wings and bodies

Description: "Studies of various arrangements of wings and bodies designed to provide favorable wave interference at supersonic speeds lead to the problem of determining the minimum possible valve of the wave resistance obtainable by any disposition of the elements of an aircraft within a definitely prescribed region. Under the assumptions that the total lift and the total volume of the aircraft are given, conditions that must be satisfied if the drag is to be a minimum are found. The report concludes with … more
Date: February 1956
Creator: Jones, Robert T.
open access

On Panel Flutter and Divergence of Infinitely Long Unstiffened and Ring-Stiffened Thin-Walled Circular Cylinders

Description: "A preliminary theoretical investigation of the panel flutter and divergence of infinitely long, unstiffened and ring-stiffened thin-walled circular cylinders is described. Linearized unsteady potential-flow theory is utilized in conjunction with Donnell's cylinder theory to obtain equilibrium equations for panel flutter. Where necessary, a simplified version of Flugge's cylinder theory is used to obtain greater accuracy. By applying Nyquist diagram techniques, analytical criteria for the locat… more
Date: January 11, 1956
Creator: Leonard, Robert W. & Hedgepeth, John M.
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