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At least 91 records · Page 5

Lateral Stability and Control Characteristics of a Four-Propeller Deflected-Slipstream VTOL Model Including the Effects of Ground Proximity

The investigation of the lateral-directional stability and control characteristics of a four-propeller deflected-slipstream VTOL model in the transition speed range was conducted in the 17-foot test section of the Langley 300-MPH 7- by 10-foot tunnel. A large fairing on top of the rear fuselage was needed to eliminate directional instability in the power-off flaps-retracted condition. Even with this fairing some instability at small sideslip angles remained for power-on conditions with low flap deflections. The configuration exhibited a high level of dihedral effect which, coupled with the directional instability, will probably produce an undesirable Dutch roll oscillation.

Kuhn, Richard E.↗

Space shuttle: Directional and lateral stability and interference effects of cruise engine location on a 0.015 scale space shuttle

The results are presented that were obtained from a wind tunnel tests to improve space shuttle booster baseline lateral-directional stability, control characteristics, and cruise engine location optimization. Tests were conducted in a 7 x 10-foot transonic wind tunnel. The model employed was a 0.015-scale replica of a space shuttle booster. The three major objectives of this test were to determine the following: (1) force, static stability, and control effectiveness characteristics for varying angles of positive and negative wing dihedral and various combinations of wing tip and centerline dorsal fins; (2) force and static stability characteristics of cruise engines location on the body below the high aerodynamic canard; and (3) control effectiveness for the low-mounted wing configuration. The wing dihedral study was conducted at a cruise Mach number of 0.40 and simulated altitude of 10,000 feet. Portions of the test were conducted to determine the control surfaces stability and control characteristics over the Mach number range of 0.4 to 1.2. The aerodynamic characteristics determined are based on a unit Reynolds number of approximately 2 million per foot. Boundary layer trip strips were employed to induce boundary layer transition.

Buchholz, R. E.↗

Lateral stability and control derivatives extracted from space shuttle Challenger flight data

Flight data taken from six flights of the Space Transportation System shuttle Challenger (STS-6, 7, 8, 11, 13 and 17) during atmospheric entry are analyzed to determine the shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The vehicle stability and control surface effectiveness are compared across the flights and to preflight predicted values.

Schiess, James R.↗

Lateral stability and control derivatives extracted from five early flights of the space shuttle Columbia

Flight data taken from the first five flights (STS-2, 3, 4, 5 and 9) of the Space Transportation System Shuttle Columbia during entry are analyzed to determine the Shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The estimated parameters are compared across the five flights and to preflight predicted values.

Schiess, J. R.↗

The influence of lateral stability on disturbed motions of an airplane with special reference to the motions produced by gusts

Disturbed lateral motions have been calculated for a hypothetical small airplane with various modifications of fin area and dihedral setting. The modifications of the airplane include changes of dihedral and changes of weathercock stability. Fin area and wing dihedral were found to be of primary importance in side gusts. It was found that the rolling action of the wing with as much as 5 deg dihedral was distinctly unfavorable, especially when the weathercock stability was small. It is pointed out that the greatest susceptibility to lateral disturbances lies in the inherent damping and coupling moments developed by the wing.

Jones, R. T.↗

Longitudinal and Lateral Stability Characteristics of a 0.04-Scale Model of the Lockheed F-104A Airplane at Mach Numbers of 1.82 and 2.01. Coord. No. AF-245

An investigation has been made in the Langley 4 by 4-foot supersonic pressure tunnel at Mach numbers of 1.82 and 2.01 to determine the longitudinal and lateral static-stability characteristics of a 0.04-scale model of the Lockheed F-104A airplane. The effects of a modified vertical tail, several ventral-fin arrangements, and several external store arrangements were also determined. The tests were made at Reynolds numbers of 1.02 (exp 6) and 1.382 (exp 6), respectively, based on the wing mean geometric chord. The tests were made of combined angles of attack and sideslip that varied from about -4 deg. to about 20 deg.

Spearman, M. Leroy↗

Lateral stability and control derivatives of a jet fighter airplane extracted from flight test data by utilizing maximum likelihood estimation

A method of parameter extraction for stability and control derivatives of aircraft from flight test data, implementing maximum likelihood estimation, has been developed and successfully applied to actual lateral flight test data from a modern sophisticated jet fighter. This application demonstrates the important role played by the analyst in combining engineering judgment and estimator statistics to yield meaningful results. During the analysis, the problems of uniqueness of the extracted set of parameters and of longitudinal coupling effects were encountered and resolved. The results for all flight runs are presented in tabular form and as time history comparisons between the estimated states and the actual flight test data.

Parrish, R. V.↗

Longitudinal and Lateral Stability and Control Characteristics of Various Combinations of the Component Parts of Two Canard Airplane Configurations at Mach Numbers of 1.41 and 2.01

An investigation has been conducted in the Langley 4- by 4-foot supersonic pressure tunnel to determine the aerodynamic characteristics in pitch and sideslip of a generalized canard airplane model. Two wings of equal area but differing in plan form were investigated. The model was equipped with a trapezoidal canard surface with an area 12 percent of the wing area, a low-aspect-ratio vertical tail, and twin ventral fins. The interference effects of the canard wake on the wing result in little or no gain in the total lift at a Mach number of 1.41 but at a Mach number of 2.01 a substantial portion of the canard lift is retained with a resultant increase in total lift. Because these interference effects of the canard wake appear to be concentrated near the leading edge of the wing, the proper location of the wing leading edge with respect to the center of moments may result in a substantial increase in the moment increment provided by a canard surface even though the total lift provided by the canard is small. For these configurations the trapezoidal wing retained the most lift and had the largest favorable moment increment produced by the canards. The canard configurations have the same characteristic decrease in directional-stability with angle of attack as most conventional high-fineness-ratio supersonic configurations. Although the presence of the canard surface caused a small increase in the directional stability at a Mach number of 1.41 for the delta-wing configuration, the presence of the canards resulted in small decreases in the directional-stability level at a Mach number of 2.01 for both wing configurations. A canard deflection of 15 deg provides an increase in the positive effective dihedral approximately as large as that provided by the presence of the vertical tail. This effect of canard deflection might complicate the lateral-control problem in the case of a rolling pull-up maneuver.

Driver, Cornelius↗