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in subjects: "Oscillations"  
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Determination of lateral-stability derivatives and transfer-function coefficients from frequency-response data for lateral motions

Description: A method is presented for determining the lateral-stability derivatives, transfer-function coefficients, and the modes for lateral motion from frequency-response data for a rigid aircraft. The method is based on the application of the vector technique to the equations of lateral motion, so that the three equations of lateral motion can be separated into six equations. The method of least squares is then applied to the data for each of these equations to yield the coefficients of the equations o… more
Date: 1955
Creator: Donegan, James J.; Robinson, Samuel W., Jr. & Gates, Ordway B., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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On the Kernel function of the integral equation relating the lift and downwash distributions of oscillating finite wings in subsonic flow

Description: This report treats the Kernel function of an integral equation that relates a known prescribed downwash distribution to an unknown lift distribution for a harmonically oscillating finite wing in compressible subsonic flow. The Kernel function is reduced to a form that can be accurately evaluated by separating the Kernel function into two parts: a part in which the singularities are isolated and analytically expressed and a nonsingular part which may be tabulated. The form of the Kernel function… more
Date: 1955
Creator: Watkins, Charles E.; Runyan, Harry L. & Woolston, Donald S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A wind-tunnel test technique for measuring the dynamic rotary stability derivatives at subsonic and supersonic speeds

Description: "A method is described for measuring the dynamic stability derivatives of a model airplane in a wind tunnel. The characteristic features of this system are that single-degree-of-freedom oscillations were used to obtain combinations of rolling, yawing and pitching motions; that the oscillations were excited and controlled by velocity feedback which permitted operation under conditions unfavorable for more conventional types of oscillatory testing; and that data processing was greatly simplified … more
Date: September 20, 1954
Creator: Beam, Benjamin H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Theoretical and experimental investigation of the effect of tunnel walls on the forces on an oscillating airfoil in two-dimensional subsonic compressible flow

Description: This report presents a theoretical and experimental investigation of the effect of wind-tunnel walls on the air forces on an oscillating wing in two-dimensional subsonic compressible flow. A method of solving an integral equation which relates the downwash on a wing to the unknown loading is given, and some comparisons are made between the theoretical results and the experimental results. A resonance condition, which was predicted by theory in a previous report (NACA report 1150), is shown expe… more
Date: 1956
Creator: Runyan, Harry L.; Woolston, Donald S. & Rainey, A. Gerald
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Theoretical Investigation of the Lateral Oscillations of an Airplane With Free Rudder With Special Reference to the Effect of Friction

Description: "Charts showing the variation in dynamic stability with the rudder hinge-moment characteristics are presented. A stabilizing rudder floating tendency combined with a high degree of aerodynamic balance is shown to lead to oscillations of increasing amplitude. This dynamic instability is increased by viscous-friction in the rudder control system" (p. 147).
Date: March 4, 1943
Creator: Greenberg, Harry & Sternfield, Leonard
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Theoretical Investigation of the Rolling Oscillations of an Airplane With Ailerons Free

Description: "An analysis is made of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. The present analysis supersedes the aileron investigation contained in NACA Technical Report no. 709. The equations of motion are first written to include yawing and sideslipping, and it is demonstrated that the principal effects of freeing the ailerons can be determined without regard to these motions" (p. 255).
Date: November 19, 1943
Creator: Cohen, Doris
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A method for studying the hunting oscillations of an airplane with a simple type of automatic control

Description: "A method is presented for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in the response of the aircraft to the controls. If the steering device is actuated by a simple right-left type of signal, the series of alternating fixed-amplified signals occurring during the hunting may ordinarily be represented by a "square wave." Formulas are given expressing the respon… more
Date: May 5, 1944
Creator: Jones, Robert T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laminar-boundary-layer oscillations and transition on a flat plate

Description: This is an account of an investigation in which oscillations were discovered in the laminar boundary layer along a flat plate. These oscillations were found during the course of an experiment in which transition from laminar to turbulent flow was being studied on the plate as the turbulence in the wind stream was being reduced to unusually low values by means of damping screens. The first part of the paper deals with experimental methods and apparatus, measurements of turbulence and sound, and … more
Date: April 1943
Creator: Schubauer, G. B. & Skramstad, H. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Aerodynamic Derivatives of a Sinusoidally Oscillating Airfoil in Two-Dimensional Flow

Description: "Experimental measurements of the aerodynamic reactions on a symmetrical airfoil oscillating harmonically in a two-dimensional flow are presented and analyzed. Harmonic motions include pure pitch and pure translation, for several amplitudes and superimposed on an initial angle of attack, as well as combined pitch and translation. The apparatus and testing program are described briefly and the necessary theoretical background is presented" (p. 1).
Date: 1952
Creator: Halfman, Robert L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Theoretical Investigation of the Rolling Oscillations of an Airplane with Ailerons Free

Description: "An analysis is made of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. The present analysis supersedes the aileron investigation contained in NACA Report No. 709. The equations of motion are first written to include yawing and sideslipping, and it is demonstrated that the principal effects of freeing the ailerons can be determined without regard to these motions" (p. 1).
Date: 1944
Creator: Cohen, Doris
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Study of the Problem of Designing Airplanes With Satisfactory Inherent Damping of the Dutch Roll Oscillation

Description: "Considerable interest has recently been shown in means of obtaining satisfactory stability of the dutch roll oscillation for modern high-performance airplanes without resort to complicated artificial stabilizing devices. One approach to this problem is to lay out the airplane in the earliest stages of design so that it will have the greatest practicable inherent stability of the lateral oscillation. The present report presents some preliminary results of a theoretical analysis to determine the… more
Date: 1954
Creator: Campbell, John P. & McKinney, Marion O., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Complete Study of Longitudinal Oscillation of a VE-7 Airplane

Description: "This investigation was carried out by the National Advisory Committee for Aeronautics at Langley Field in order to study as closely as possible the behavior of an airplane when it was making a longitudinal oscillation. The airspeed, the altitude, the angle with the horizon and the angle of attack were all recorded simultaneously and the resulting curves plotted to the same time scale. The results show that all the curves are very close to damped sine curves, with the curves for height and angl… more
Date: 1924
Creator: Norton, F. H. & Brown, W. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Study of Longitudinal Dynamic Stability in Flight

Description: "This investigation was carried out by the aerodynamic staff of the National Advisory Committee for Aeronautics for the purpose of studying experimentally the longitudinal dynamic stability of airplanes in flight. The airplanes selected for this purpose were a standard rigged VE-7 advanced-training airplane and a JN4H with special tail surfaces. The airplanes were caused to oscillate by means of the elevator, then the longitudinal control was either locked or kept free while the oscillation die… more
Date: 1924
Creator: Norton, F. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Diagrams of Airplane Stability

Description: In this report a study is made of the effect on longitudinal and lateral oscillations of an airplane of simultaneous variations in two resistance derivatives while the remainder of the derivatives are constant. The results are represented by diagrams in which the two variable resistance derivatives are used as coordinates, and curves are plotted along which the modulus of decay of a long oscillation has a constant value. The same type of analysis is also carried out for the stability of the par… more
Date: 1921
Creator: Bateman, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Single-degree-of-freedom-flutter calculations for a wing in subsonic potential flow and comparison with an experiment

Description: The effect of Mach number and structural damping on single-degree-of-freedom pitching of a wing is presented. Some experimental results are compared with theory and good agreement is found for certain ranges of an inertia parameter.
Date: 1952
Creator: Runyan, Harry L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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