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Low-Speed Measurements of Rolling and Yawing Stability Derivatives of a 60 Degree Delta-Wing Model

Description: Memorandum presenting an investigation in the free-flight tunnel to determine the low-speed rolling and yawing stability derivatives of a 60 degree delta-wing model from 0 to 30 degrees angle of attack. The derivatives were measured by the free-to-damp oscillation technique and by the steady-roll technique.
Date: December 27, 1954
Creator: Johnson, Joseph L., Jr.
Partner: UNT Libraries Government Documents Department

Generalized Analysis of Experimental Observations in Problems of Elastic Stability

Description: "A generalized method of analyzing experimental observations in problems of elastic stability is presented in which the initial readings of load and deflection may be taken at any load less the critical load. The analysis is an extension of a method published by Southwell in 1932, in which it was assumed that the initial readings are taken at zero load" (p. 1).
Date: July 1938
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department

Some Effects of Nonlinear Variation in the Directional-Stability and Damping-in-Yawing Derivatives on the Lateral Stability of an Airplane

Description: Note presenting a theoretical investigation made to determine the effect of nonlinear stability derivatives on the lateral stability of the airplane. The results indicated that under certain conditions, a motion is obtained which has different rates of damping for the large and small amplitudes of motion, with very little damping at the small amplitudes.
Date: November 1950
Creator: Sternfield, Leonard
Partner: UNT Libraries Government Documents Department

Some Effects of Nonlinear Variation in the Directional-Stability and Damping-in-Yawing Derivatives on the Lateral Stability of an Airplane

Description: "A theoretical investigation has been made to determine the effect of nonlinear stability derivatives on the lateral stability of an airplane. Motions were calculated on the assumption that the directional-stability and the damping-in-yawing derivatives are functions of the angle of sideslip. The application of the Laplace transform to the calculation of an airplane motion when certain types of nonlinear derivatives are present is described in detail" (p. 1009).
Date: September 19, 1950
Creator: Sternfield, Leonard
Partner: UNT Libraries Government Documents Department

Approximate Calculation of the Static Longitudinal Stability of Airplanes

Description: It seems desirable to have some simple method for calculating quickly and with sufficient accuracy: 1) the correct position of the center of gravity; 2) the requisite tail-group dimensions; 3) and the course of the wing and tail-group moments. In out deductions, we will first replace the biplane (disregarding the effect of stagger, decalage and induced drag) by an equivalent monoplane, whose dimensions and position in space can be approximately determined in a simple manner.
Date: November 1926
Creator: Bienen, Theodor
Partner: UNT Libraries Government Documents Department

Calculation of the Lateral-Dynamic Stability of Aircraft

Description: "Graphs and formulas are given with the aid of which all the aerodynamic coefficients required for computing the lateral dynamic stability can be determined. A number of numerical examples are given for obtaining the stability derivatives and solving the characteristic-stability equation. Approximate formulas are derived with the aid of which rapid preliminary computations may be made and the stability coefficients corrected for certain modifications of the airplane" (p. 1).
Date: February 1952
Creator: Raikh, A.
Partner: UNT Libraries Government Documents Department

Supplemental Data and Calculations of the Lateral Stability of Airplanes

Description: In connection with the DVL Report 272 on the theory of the lateral stability of airplanes, the formal results are here amplified in some respects and their technical significance again briefly explained. Three numerical examples show how model tests for checking the lateral stability are to be evaluated and supplemented, if necessary, and how the stability limits depend on the design of the airplane and on the conditions of flight.
Date: April 1934
Creator: Mathias, Gotthold
Partner: UNT Libraries Government Documents Department

Investigation of Effect of Sideslip on Lateral Stability Characteristics 3: Rectangular Low Wing on Circular Fuselage With Variations in Vertical-Tail Area and Fuselage Length With and Without Horizontal Tail Surface

Description: Report presenting power-off tests made in the 6- by 6-foot test section of the stability tunnel to determine the variation of the static lateral stability characteristics with vertical-tail area, fuselage length, and wing dihedral. The results are presented as curves showing the variation of the static-lateral-stability slopes with angle of attack, and the rolling-moment, yawing-moment, and lateral-force coefficients with angle of yaw.
Date: August 1945
Creator: Hollingworth, Thomas A.
Partner: UNT Libraries Government Documents Department

A Survey of Methods for Determining Stability Parameters of an Airplane From Dynamic Flight Measurements

Description: Note presenting a discussion of various methods of reducing to stability parameter form the response to sinusoidal and transient disturbances, using the simplified longitudinal motion of an idealized airplane as an illustrative example. Most of this report is concerned with methods of determining transfer-function coefficients rather than stability derivatives. Examples are provided for a simplified case of longitudinal motion, but the methods presented are applicable to other, more complicated types of motion.
Date: April 1951
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department

Application of the Laplace Transformation to the Solution of the Lateral and Longitudinal Stability Equations

Description: Note presenting the application of the Laplace transformation to the solution of the lateral and longitudinal stability equations. The expressions for the time history of the motion in response to a sinusoidal control motion are derived for the general case in which all initial measurements are assumed different from zero.
Date: January 1950
Creator: Mokrzycki, G. A.
Partner: UNT Libraries Government Documents Department

The Stability Derivatives of Low-Aspect-Ratio Triangular Wings at Subsonic and Supersonic SPeeds

Description: "Low-aspect-ratio wings having triangular plan forms are treated on the assumption that the flow potentials in planes at right angles to the long axis of the airfoils are similar to the corresponding two-dimensional potentials. Pressure distributions caused by downward acceleration, pitching, rolling, sideslipping, and yawing are obtained for wings with and without dihedral. The stability derivatives calculated from these distributions are expected to apply at both subsonic and supersonic speeds, with the exception of the transonic region, up to a limiting speed at which the triangle is no longer narrow compared with the Mach cone from its vertex" (p. 1).
Date: September 1948
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department

Investigation at low speeds of the effect of aspect ratio and sweep on rolling stability derivatives of untapered wings

Description: A low-scale wind-tunnel investigation was conducted in rolling flow to determine the effects of aspect ratio and sweep (when varied independently) on the rolling stability derivatives for a series of untapered wings. The rolling-flow equipment of the Langley stability tunnel was used for the tests. The data of the investigation have been used to develop a method of accounting for the effects of the drag on the yawing moment due to rolling throughout the lift range.
Date: January 19, 1949
Creator: Goodman, Alex & Fisher, Lewis R.
Partner: UNT Libraries Government Documents Department

Damping in a roll of a missile configuration with a modified triangular wing and a cruciform tail at a Mach number of 1.52

Description: Report presenting the damping-in-roll stability derivatives of a missile configuration and its components as determined experimentally and theoretically. The experimental damping derivative of the wing-body combination was found to be 67 percent of its theoretical value. Results are given for the wing-body combination, the tail-body combination, and the wing-tail-body combination.
Date: March 6, 1951
Creator: Scherrer, Richard & Dennis, David H.
Partner: UNT Libraries Government Documents Department

The effects on dynamic lateral stability and control of large artificial variations in the rotary stability derivatives

Description: This report presents the results of an investigation conducted in the Langley free-flight tunnel to determine the effects of large artificial variations of several rotary lateral-stability derivatives on the dynamic lateral stability and control characteristics of a 45 degree sweptback-wing airplane model. Calculations of the period and damping of the lateral motions and of the response to roll and yaw disturbances were made for correlation with the experimental results. The calculated results were in qualitative agreement with the experimental results in predicting the general trends in flight characteristics produced by large changes in the stability derivatives, but in some cases the theory with the assumption of zero lag was not in good quantitative agreement with the experimental results.
Date: June 20, 1952
Creator: Schade, Robert O. & Hassell, James L., Jr.
Partner: UNT Libraries Government Documents Department

A Preliminary Study of the Problem of Designing High-Speed Airplanes With Satisfactory Inherent Damping of the Dutch Roll Oscillation

Description: Report presenting an investigation to create a design for fighter airplanes to have better inherent stability than most current designs. The main purpose of this design change is to obtain satisfactory stability of the Dutch roll oscillation without complicated artificial stabilizing devices. Results regarding the causes of inadequate dutch roll stability, means of improving dutch roll stability, and application of experimental design results to actual airplanes are provided.
Date: October 1953
Creator: Campbell, John P. & McKinney, Marion O., Jr.
Partner: UNT Libraries Government Documents Department

A Study to Determine the Relationship Between Emotional Stability and Academic Accomplishment

Description: This study is concerned with the determination of the relationship that exists between levels of emotional stability and academic accomplishment among students of Business Administration at North Texas State College. It is the hypothesis of this study that a positive relationship exists between levels of emotional stability and academic achievement among students of Business Administration at North Texas State College and that the degree of this relationship can be determined.
Date: June 1961
Creator: Latham, William Robert
Partner: UNT Libraries

A Study on the Stability of Self-concept

Description: There are two major purposes of this study. First, it will attempt to ascertain whether self-concept, as measured by a self-concept scale, will fluctuate significantly due to a recent ego inflating or deflating experience, and if so, how lasting and in what areas are the effects. Secondly, it will note whether or not the low self-concept individual is more susceptible to changes in self-concept due to these environmental changes than the high self-concept individual.
Date: January 1964
Creator: Collman, Robert Bernard
Partner: UNT Libraries

Airplane Stability in Taxying

Description: The stability analysis of an airplane while rolling is much more simplified to the extent that it can be obtained for numerical data which can be put to practical use in the design of landing gear dimensions. Every landing gear type attains to a critical ground friction coefficient that decides the beginning of instability, i.e., nosing over. This study has, in addition, a certain interest for the use of wheel brakes.
Date: September 1932
Creator: Anderlik, E.
Partner: UNT Libraries Government Documents Department

Airplane Stability Calculations and Their Verification by Flight Tests

Description: For some time, the designers of airplanes have begun to occupy themselves with the question of longitudinal stability. In their quest to simplify calculation and data collection, the designers have attached the greatest importance to the coefficient of initial longitudinal stability. In this study a diagram was constructed from the data of the tunnel tests, which depends neither on the position of the center of gravity nor of the angle of deflection of the elevators. This diagram is constructed by means of straight lines drawn through the metacenters of the complete airplane, in a direction parallel to the tangents to the polar of the airplane relative to a system of axes fixed with reference to the airplane.
Date: July 1922
Creator: Rota, Augusto
Partner: UNT Libraries Government Documents Department

Airplane Balance

Description: The authors argue that the center of gravity has a preponderating influence on the longitudinal stability of an airplane in flight, but that manufacturers, although aware of this influence, are still content to apply empirical rules to the balancing of their airplanes instead of conducting wind tunnel tests. The author examines the following points: 1) longitudinal stability, in flight, of a glider with coinciding centers; 2) the influence exercised on the stability of flight by the position of the axis of thrust with respect to the center of gravity and the whole of the glider; 3) the stability on the ground before taking off, and the influence of the position of the landing gear. 4) the influence of the elements of the glider on the balance, the possibility of sometimes correcting defective balance, and the valuable information given on this point by wind tunnel tests; 5) and a brief examination of the equilibrium of power in horizontal flight, where the conditions of stability peculiar to this kind of flight are added to previously existing conditions of the stability of the glider, and interfere in fixing the safety limits of certain evolutions.
Date: June 1921
Creator: Huguet, L.
Partner: UNT Libraries Government Documents Department

Airplane Strength Calculations and Static Tests in Russia: An Attempt at Standardization

Description: We are here giving a summary of the rules established by the Theoretical Section of the Central Aerodynamic Institute of Moscow for the different calculation cases of an airplane. It appears the engineers of the Aerodynamic Institute considered only thick or medium profiles. For these profiles they have attempted to increase the safety when the center of pressure moves appreciably toward the trailing edge.
Date: September 1928
Partner: UNT Libraries Government Documents Department

Aerodynamic Characteristics at Supersonic Speeds of a Series of Wing-Body Combinations Having Cambered Wings With an Aspect Ratio of 3.5 and a Taper Ratio of 0.2: Effect at M = 2.01 of Nacelle Shape and Position on the Aerodynamic Characteristics in Pitch of Two Wing-Body Combinations with 47 Degree Sweptback Wings

Description: Memorandum presenting an investigation at M = 2.01 in the 4- by 4-foot supersonic pressure tunnel to determine the effect of a series of nacelles on the longitudinal stability characteristics of a sweptback wing-body combination. Nacelle shape and position were varied on a configuration with a 6-percent-thick wing with an aspect ratio of 3.5, a taper ratio of 0.2, and 47 degrees of sweep at the quarter chord.
Date: July 25, 1952
Creator: Driver, Cornelius
Partner: UNT Libraries Government Documents Department

Statical Longitudinal Stability of Airplanes

Description: This report, which is a continuation of the "Preliminary report on free flight testing" (report no. NACA-TR-70), presents a detailed theoretical analysis of statical stability with free and locked controls and also the results of many free flight test on several types of airplanes. In developing the theory of stability with locked controls an expression for pitching moment is derived in simple terms by considering the total moment as the sum of the moments due to wings and tail surface. This expression, when differentiated with respect to angle of incidence, enables an analysis to be made of the factors contributing to the pitching moment.
Date: 1921
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department