Abstract: A method of reducing the bending moment effect of wind gust loads acting on the wing of an aircraft involves adjusting the aerodynamic configuration of the wing so as to alter the distribution of lift generated by the wing during phases of flight in which critical wind gusts are expected to occur. Particularly, during climb and descent phases of flight below cruise altitude, the lift generated by outboard portions of the wings is reduced while the lift generated by inboard portions of the wings is increased. Thereby, the 1 g basis load acting on the outboard portions of the wings is reduced, and consequently the total load applied to the outboard portions of the wings, resulting from the 1 g basis load plus the additional wind gust load, is correspondingly reduced. This leads to a reduction of the bending moments effective on the wings, and of any rolling moment effective on the aircraft.

Abstract: A flight control surface actuation system is provided in which a plurality of actuators (6-13) are connected to one another in order to synchronize their operation. Each actuator has its own gearbox such that the torque transmitted in the synchronizing element is kept low.

Abstract: A method and apparatus for reducing the unwanted sideways motion of an airplane by reducing the lateral side loads and upsets caused by atmospheric turbulence and gusts is disclosed. A rudder modification command that causes the rudder command of the airplane to be changed in a manner that relieves the net force across the vertical stabilizer of the airplane caused by atmospheric turbulence and gusts is produced. More specifically, the pressure differential across opposite sides of the vertical stabilizer is measured and used to produce a rudder deflection value that is roll rate and yaw rate compensated. The compensated deflection value is high-pass filtered with a corner frequency that is twenty-five percent (25%) of the Dutch roll frequency of the airplane. The result is a first rudder deflection value that is subtractively combined with a second rudder deflection value.

Abstract: An aircraft modal suppression system which recognizes that the frequency and phase of the body bending mode varies when the weight of the aircraft differs from the design gross weight. An active damper notch filter which is tabulated as a function of aircraft gross weight is utilized, thereby enabling not only the frequency, but also the width and depth of the notch filter to vary according to the gross weight of the aircraft.

Abstract: A controller for reducing unwanted sideways motion of an aircraft by reducing lateral side loads, resulting from air mass, turbulence and gusts. The controller functions in a manner that in the presence of higher frequency side loads, the rudder is caused to move in a relieving direction so that the net force across the vertical stabilizer is reduced. A pressure differential across opposite sides of the vertical stabilizer is measured and used to generate a first rudder deflection signal. To maintain stability of the aircraft, a beta-dot signal from the yaw damper module is gain adjusted and filtered to generate a second rudder deflection signal which is added to the first rudder deflection signal. The resulting combined signal reduces lateral side loads at higher frequencies without comprising aircraft directional stability.

Abstract: The present invention relates to a process for the automatic control of the control surfaces of an aircraft for the low speed compensation of a lateral path deviation, in which beyond a given deflection threshold (20) of the deflected rudder (17), there is a control of a deflection, proportional to the exceeding of the threshold, of the wing surfaces (13, 14) of one of the two wings (18), said wing being that on the side of the deflected rudder (17), so as to provide a drag supplement to said wing and therefore yaw on the aircraft.Application to the take-off of large civil transport aircraft.

Abstract: An autopilot system including parameter identification circuits wherein the function of the torque and the function of the translational force on a missile are unknown and varying (including approaching zero).

Abstract: A system for reducing the forces applied to the wings of an aircraft in flight includes an accelerometer for measuring the vertical acceleration of the aircraft and generators for generating signals to control the aerodynamic surfaces in the wings of the aircraft as a function of the acceleration measured by the accelerometer. The control signal generator is not activated except when the vertical acceleration exceeds a predetermined value.

Abstract: In order to realize an optimum operating condition of a leading-edge flap, a wind-direction sensor and a load sensor are provided at a leading-edge flap or at each of a plurality of parts of a leading-edge flap divided along the direction of a wing span. An operational control mechanism is also provided for calculating an optimum angle of the leading-edge flap on the basis of information supplied from the wind-direction sensor and the load sensor, and for operating an actuator for varying the angle of the leading-edge flap so as to attain the calculated optimum angle. The wind-direction sensor is preferably either a hot-wire anemometer or a pressure sensor.

Abstract: The gust alleviation system was designed to be an add-on to any existing g-command flight control system. The system assumes that there already exists, a stability augmentation system which will hold the aircraft's attitude. This system minimizes the interaction of the gust alleviation system with the existing flight control system. The gust alleviation system picks off the stick displacement signal and the aircraft normal acceleration sensor signal and processes this information. The outputs of the gust alleviation system are added back respectively to the existing flap command signal and the aircraft's original stability augmentation loop.

Abstract: An aircraft guidance system for optimizing the flight path of an aircraft in the presence of a windshear maximizes the time the aircraft remains in the air and the distance traveled regardless of the magnitude of the windshear, in the presence of horizontal or vertical windshear components, while effectively minimizing excitation of the aircraft's phugoid mode. A flight path angle is commanded sufficient to clear any obstacle that may be found in the airport vicinity. For longitudinal or horizontal shears, a slightly positive constant flight path angle which is a function of the magnitude of the vertical wind is added to the slightly positive flight path angle command to produce a modified command that compensates for the decrease in flight path angle relative to the ground caused by the vertical wind. The system inhibits exceeding stick shaker angle of attack by reducing the command signal until the actual angle of attack is equal to or less than the stick shaker angle of attack.

Abstract: The present invention constitutes a system for generating an elevator command signal for directing a pilot in guiding his aircraft along a path effective for recovering from hazardous windshear conditions. The system includes a descending mode guidance subsystem (10), an ascending mode guidance subsystem (12) and a switching mechanism (14) for shifting between the two subsystems. The descending mode subsystem includes an acceleration generator (20), a flight path command generator (22), a flight path error generator (24), a descending mode pitch error generator (26), an airspeed control device (28) and a descending mode signal controller (30). These components are connected serially together and operate to form an elevator command signal corresponding to the acceleration required to halt the descent of the aircraft by a fixed altitude level.

Abstract: This invention provides a system for enhancing the performance of an aircraft during flight. The aircraft, which includes at least two control surfaces, such as stabilon and trailing edge flaps, includes devices for: generating a signal representative of the optimum normal acceleration from signals representative of the aircraft's flight status, generating a signal representative of the aircraft's actual normal acceleration, comparing the optimum signal to the actual signal, and generating a command to alter the position of either one or both of the aircraft's control surfaces to reduce any differences between the optimum and actual normal acceleration signals.

Abstract: Strain gages embedded in an upper skin structure portion of the wing, near the centerline axis, measures centerline moment and produces a feedback signal used for adjusting the control surfaces of the wing, to produce stabilizing forces. This enables the wings to be designed primarily for strength, not stiffness.

Abstract: To reduce buffeting caused by separation on the wings of an aircraft, a parameter representing the buffeting in amplitude, frequency and phase is measured. The measuring signal is subjected to filtering intended to establish the characteristics of at least one mode of vibration of the wings and, by actuating a control surface according to a non-stationary law, in a localized region the wings, of alternate stresses are generated whose amplitude and phase are automatically determined to dampen one or several modes of vibration of the wings.

Abstract: In order to achieve fine control of the velocity of an aircraft flying a predetermined flight path at a predetermined nominal speed in the presence of such perturbations as wind gusts, a low inertia, fast acting device is extended or deployed into the aircraft dragstream and is rapidly position-modulated in response to sensed acceleration/deceleration to instantaneously slightly alter the total system drag to an amount which causes the aircraft to maintain the predetermined velocity. Among the exemplary alternative low inertia devices disclosed are: fuselage and wing mounted flaps which are rapidly more or less extended, a trailing cable which is rapidly reeled in or out, and a trailing inflatable member whose degree of inflation is rapidly changed, all in response to sensed acceleration/deceleration from an on-board system.

Abstract: A device for an automatically controllable off-loading of aircraft wings, arranged between the aircraft wing structure and the control surfaces, spoilers or flaps and is a single device or in the form of a plurality of devices respectively assigned to the control surface along the wing span and automatically reduces the additional loading at the aircraft wing generated by gust-and maneuver loads as well as increases the flutter speed by a dampening circuit in an electro-hydraulic manner.

Abstract: A windshear warning apparatus which separately compares a plurality of signals derived from horizontal and vertical inertial acceleration and air mass acceleration components to indicate incipient windshear. The compared signals are substantially equal under normal wind conditions but are significantly different under windshear conditions. A signal proportional to the product of the magnitude and rate of change of the total or resultant inertial acceleration of the aircraft is used to provide a warning of a significant windshear condition.

Abstract: On an aircraft having spoilers on the wing, the spoilers are converted, according to this invention, following the ACT philosophy, for use in countering gust effects. Accordingly, a sensor of gusts is arranged to transmit warning of the arrival of a significant gust to a spoiler operator which, taking into account airspeed, deploys the spoilers in a mode so that a phase of spoiler generated lift decrement is timed to coincide with effective arrival of the gust.

Abstract: An aircraft carries a pressure indicator well in advance, which may record barometric pressure of vertical air currents. The indicator reading is converted to electric current and averaged over a short period. The unaveraged current at a given position of the pressure indicator is recorded, delayed, read out, compared with the average current and the error current used to actuate wing flaps at the instant the wings pass over the given position, so as to adjust the wing lift for any difference in conditions as the wings move forward. Similarly the current recorded at the instant the pressure indicator was at a given point is delayed, compared with the average current at the instant the tail structure passes over the given point, and the error current is used to adjust elevators for any difference in pressure as the tail structure moves from its first position to the position of the pressure indicator at the given instant.

Abstract: A thin, high performance swept wing of the tapered type with an improved leading edge characterized by (1) camber that increases from a minimum near the wing root to a maximum near the wing tip, and (2) substantially a constant leading edge radius extending substantially across the wing span which defines a "blunt" contour. The wing in combination with a T-tail aircraft with a stick shaker/pusher activated by a rate of change of angle of attack sensor and optionally a strake between the leading edge and a wing tip tank which intrinsically combine to define a system that enhances aircraft performance by reducing minimum airspeed without impairing aircraft performance at high subsonic Mach (M) numbers.