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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

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

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 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

Wind-Tunnel Investigation of the Low-Speed Static Stability and Control Characteristics of a Model of Bell MX-776

Description: An investigation has been made in the Langley stability tunnel to determine the low-speed static stability and control characteristics of a model of the Bell MX-776. The results of the investigation indicated that the basic model configuration was longitudinally stable in the angle-of-attack range from about -16 deg. to 16 deg. but that the stability was a minimum near O deg angle of attack. The data indicated an aerodynamic-center position about 0.64 body diameters behind the center of gravity at low angles of attack. Reduction in the size of the front horizontal fins increased the longitudinal stability. With 20 percent of the span of the normal front horizontal fins cut off the aerodynamic center was about 1.04 body diameters behind the center of gravity, and with front horizontal fins having the same area as the front vertical fins, the aerodynamic center was 2.26 body diameters behind the center of gravity (at low angles of attack).
Date: July 6, 1949
Creator: Queijo, M. J. & Michael, W. H., Jr.
Partner: UNT Libraries Government Documents Department

Supersonic Wave Interference Affecting Stability

Description: Some of the significant interference fields that may affect stability of aircraft at supersonic speeds are briefly summarized. Illustrations and calculations are presented to indicate the importance of interference fields created by wings, bodies, wing-body combinations, jets, and nacelles.
Date: March 8, 1958
Creator: Love, Eugene S.
Partner: UNT Libraries Government Documents Department

Flight, analog-simulator, and analytical studies of an automatically controlled interceptor which uses a bank-angle-error computer for lateral commands

Description: Report presenting the tracking performance of an automatically controlled interceptor in which the deflection channel incorporated a bank-angle-error computer that commanded rolling velocities of the interceptor proportional to the computed bank-angle errors. Results regarding gravity terms included in bank-angle-error computation and a comparison of modified system using bank-angle-error computer with the prototype system are provided.
Date: August 11, 1958
Creator: Cheatham, Donald C. & Brissenden, Roy F.
Partner: UNT Libraries Government Documents Department

The flexible mounting of an airplane engine

Description: Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.
Date: July 1923
Creator: Kutzbach, K.
Partner: UNT Libraries Government Documents Department

Flight measurements of the dynamic longitudinal stability of several airplanes and a correlation of the measurements with pilots' observations of handling characteristics

Description: The dynamic longitudinal stability characteristics of eight airplanes as defined by the period and damping of the longitudinal oscillations were measured in flight to determine the degree of stability that may be expected in conventional airplanes. An attempt was made to correlate the measured stability with pilots' opinions of the general handling characteristics of the airplanes in order to obtain an indication of the most desirable degree of dynamic stability. The results of the measurements show that the period of oscillation increases with speed. At low speeds a range of periods from 11 to 23 seconds was recorded for the different airplanes. At high speeds the periods ranged from 23 to 64 seconds. The damping showed no definite trend with speed.
Date: July 15, 1936
Creator: Soulé, Hartley A.
Partner: UNT Libraries Government Documents Department

Flight tests of a glider model towed by twin parallel towlines

Description: From Summary: "The stability characteristics of a glider towed by twin parallel towlines have been studied in the NACA free-flight tunnel. A preliminary theoretical analysis of the stability of a glider restrained from yawing was followed by an experimental investigation of the stability of a model towed from fixed tunnel points in such a way as to simulate tow in level flight. The results of the tests confirm the theoretical analysis and indicate that a pilotless, stable, towed-glider system is possible when twin parallel towcables are used."
Date: April 1943
Creator: Pitkin, Marvin & McKinney, Marion O., Jr.
Partner: UNT Libraries Government Documents Department

Flight Measurements of the Stability Characteristics of the Bell X-5 Research Airplane in Sideslips at 59 Deg Sweepback

Description: Flight measurements of the stability characteristics of the Bell X-5 research airplane at 59 deg sweepback were made in steady sideslips at Mach numbers from 0.62 to 0.97 at altitudes ranging between 35,000 and 40,000 feet. The results showed that the apparent directional stability was positive and increased at Mach numbers above 0.90. The apparent effective dihedral was positive and high, increasing at Mach numbers above 0.75. The cross-wind force coefficient per degree of sideslip was positive and increased rapidly at Mach numbers above 0.94.
Date: February 11, 1953
Creator: Childs, Joan M
Partner: UNT Libraries Government Documents Department

Flight measurements of the velocity distribution and persistence of the trailing vortices of an airplane

Description: Report regarding the measurement of velocity distribution and persistence of the trailing vortices of a propeller-driven fighter-type airplane. Vortex strength did not decrease appreciably up to 35 seconds after the vortices had been shed. When flying in the trailing wake of another airplane, the pilot reported that it was difficult to maintain a precise course and that the disturbance was similar to severe turbulence.
Date: March 1955
Creator: Kraft, Christopher C., Jr.
Partner: UNT Libraries Government Documents Department

An investigation of a supersonic aircraft configuration having a tapered wing with circular-arc sections and 40 degree sweepback: Static longitudinal stability and control characteristics at a Mach number of 1.59

Description: Report presenting an investigation in the 4- by 4-foot supersonic tunnel to determine the static longitudinal stability and control characteristics of a supersonic aircraft configuration at a Mach number of 1.59. The model had a 40 degree sweptback tapered wing with 10-percent-thick circular-arc sections normal to the quarter-chord line.
Date: June 29, 1950
Creator: Spearman, M. Leroy & Hilton, John H., Jr.
Partner: UNT Libraries Government Documents Department

An instrument for recording the position of airplane control surfaces

Description: N.A.C.A. has developed an instrument which makes a continuous record of the angular position of the control surfaces of an airplane, not only in steady flight but during acrobatics as well. It has proven useful in researches into stability and controllability, and from records obtained from it many otherwise obscure details of piloting technique have been available for the instruction of pilots, from novices to seasoned experts.
Date: August 1923
Creator: Ronan, K. M.
Partner: UNT Libraries Government Documents Department