Abstract: A helicopter stabilator, combining the functions of tail stabilizer and aircraft elevator, has its angle of incidence with respect to the helicopter controlled by means of a pair of reversible actuators acting in series, controlled in a closed-loop fashion by electronic hardware, the controls being disconnected when the actuators fail to track within a threshold disparity of either position or rate of change of position of each other. A test switch introduces an imbalance to test the fault circuitry. The stabilator is biased to assume a maximum incidence position at low speeds, including hover; and inputs from airspeed and collective pitch position cause it to assume a substantially level position at higher, cruise speeds. A pitch rate gyro input controls the stabilator for stable flight against pitch-inducing flight commands and external effects, such as gusts.

Abstract: An aircraft instrument comprising equipment for providing a first signal which is a function of airspeed and suitable for use in controlling an aircraft by variation of the airspeed to a predetermined value, an apparatus for providing a second signal which is a function of lift and suitable for use in controlling the aircraft by variation of the airspeed to adjust the lift to a predetermined value, and a selecting apparatus arranged to apply the second signal to a signal utilization mechanism for controlling the aircraft in accordance with said second signal except when said second signal falls below a predetermined datum level, which represents a safe margin above stall, whereupon the first signal is applied to the signal utilization mechanism, the selecting apparatus being arranged to provide a transition between control by the first signal and control by the second signal which is shorter than a transition between control by the second signal and control by the first signal.

Abstract: This invention relates to a process for preventing undesired contact with land or water by low-flying aircraft which are assigned a minimum altitude and which are provided with instruments for measuring altitude, airspeed, angle of path, and transverse acceleration,Comprising measuring the rate of descent (H),transverse acceleration (b.sub.Q), when gravitational acceleration is eliminated,And altitude (H) to thereby ascertain whether the aircraft is above a given limiting altitude (H.sub.limit) determined from its ability for transverse acceleration and its flight data,And correcting the aircraft by the maximum feasible transverse acceleration (b.sub.Q max) when for a given measured value of altitude (H), the altitude is below the limiting altitude (H.sub.limit).

Abstract: A system for displaying to the pilot an indication to enable him to fly to a desired air speed and angle of attack, especially on takeoff. An artificial angle of attack error signal is generated from actual and desired air speeds and corrected by adding to it a differentiated pitch signal. The resultant calculated angle of attack error is displayed to the pilot unless flying to that indication would result in exceeding the actual maximum or minimum angle of attack limits, in which case an indication based on the actual exceeded limit is displayed.

Abstract: A speed control device for moving objects which can quickly change the speed of said object from one speed to another selected speed without overshooting comprising means for generating a signal representing the difference between the actual speed and the desired speed and adding a constant bias to said difference signal if said signal exceeds a predetermined value so that said biased difference signal will actuate an actuating means to move the object more quickly toward the desired set speed and to use and integrate the unbiased difference signal when said difference signal is below said predetermined value, which integration can be used to send smaller signals to the actuating means as the moving object approaches the desired set speed so as to prevent overshooting.

Abstract: The inventive system requires that normal approach indicated airspeed and a predetermined approach groundspeed be used as the approach criteria, whichever is the least, compared to its own predetermined index value. These two values are the commanding functions fed to a fast/slow indicator and to any auto-throttle device on the approach, along with a "caution tailwind" warning device to warn the pilot whenever the groundspeed exceeds true airspeed by 5 knots or more, for example. If this warning activates, he should consider cancelling the approach and choose an approach from a different direction, determined by surface wind and his drift at the time of cancellation. This condition is caused by a tailwind component at altitude, the value of which the pilot can determine from his airspeed and groundspeed indications.

Abstract: A pilot guidance system that computes and displays pitch and speed steering commands is automatically operated during the post-takeoff climb (at specified times clocked from the start of the takeoff run), to present commands that assist the pilot in cutting (and later in restoring) thrust for a predetermined interval to reduce engine noise, and in guiding the aircraft in a safe, gentle climb over the proximate community. The specified times (unique for each model of aircraft, airport, runway and departure flight path), synchronize the thrust cutback interval with the boundaries of the community in line with chosen departure path.

Abstract: An interconnect system between an off-center-line gun of an aircraft and the aircraft rudder control. When the off-center gun is fired, the trigger actuation creates a signal modified by dynamic compressible pressure Q.sub.c to cause the interconnect system to automatically deflect the rudder an amount to cancel the yaw moment produced by the gun firing. Circuitry is also disclosed to additionally compensate for any yaw moment which may arise from an extendable gun gas deflector door. The full specification must be consulted for an understanding of the invention.

Abstract: An automatic flight control apparatus for a rotary wing aircraft for controlling the flight condition by utilizing a signal representing the air speed of the aircraft which is added to a bias signal corresponding to the attitude of the aircraft in hovering condition, which added signal is used as a "trim value" signal representing the attitude of the aircraft in a balanced relation to air speed at every instance. A signal representing the difference between said trim value signal and the attitude signal is used as an attitude/speed error signal and is added with the signal representing the difference between the ground speed and the set speed for performing control of the aircraft condition.

Abstract: An automatic flight controller for rotary wing aircraft having a setting apparatus for setting the device for the distance from a starting distance signal, a speed signal, and a remaining distance signal corresponding to the remaining distance from the starting spot to the hovering spot whereby the flight of the aircraft can be controlled in accordance with the remaining distance signal. A ground speed signal from a ground speed detecting device is integrated to obtain a signal corresponding to the flight distance from the starting spot and a remaining distance signal is then produced which is equal to the difference between the starting distance signal and the flight distance signal, and, through a function amplifier, a reference speed signal is obtained which corresponds to the remaining distance to be flown at every instance. This reference speed signal is compared with the actual ground speed to provide a speed difference signal which is used as a control signal for controlling the speed of the aircraft.

Abstract: Signals representative of the acceleration of an aircraft due to the change in flight path angle are coupled through a high pass filter (washout circuit) to obtain a short term compensation signal (V.sub.comp) which signal is further coupled to a low pass filter which provides short term integration to obtain the compansation signal (.DELTA. V.sub.comp) representative of change in speed in response to change in flight path angle. These compensation signals (V.sub.comp) and (.DELTA. V.sub.comp) are summed respectively with signals representative of longitudinal acceleration (or thrust control damping) and air speed error (or thrust control reference) to inhibit short term thrust control of the aircraft due to small flight path angle perturbations thereby improving the manual path control handling quality and the stability of the aircraft by the automatic control system. A modification of the system is disclosed for avoiding sensor noise developed by the .alpha.

Abstract: A voltage controlled oscillator provides a pulse signal which, when frequency scaled, is representative of aircraft velocity. Pulses representative of passage of the aircraft over distance intervals are coupled to one input of a comparator-integrator, and the VCO output pulses are further divided and coupled to the other input terminal of the comparator-integrator. The integration voltage controls the VCO. The VCO signal is frequency scaled and fed to a counter, the output count of which is strobed periodically and decoded to yield velocity.

Abstract: An automatic throttle system operable during all flight regimes includes automatic gain control apparatus for minimizing changes in engine thrust during the cruise mode caused by air mass turbulence and provides desirable response to commanded changes in air speed or flight path while maintaining desirable response to large magnitude wind shears. The gain of the air speed error signal is controlled as a function of Mach or true air speed and the gain of the throttle rate command signal normally controlling the engine throttle servo motor is controlled as a function of the commanded change in air speed, the air speed error, the aircraft's Mach or true air speed, and altitude rate by a real time logical control system.

Abstract: A vertical navigation steering control for aircraft for providing vertical steering of an aircraft along flight paths defined by waypoints which recognizes the problems introduced by lateral steering and accounts for shortening of horizontal distance between waypoints due to lateral path changes. Further features include means for capturing a NAV path, following a path between waypoints, transitioning from one path to another at a waypoint, and means for protection against excessive climb rates.

Abstract: A gravity survey and aircraft guidance system comprises a pendulum clock mounted in an aircraft in level flight, having a pendulum bob with a signal sender mounted thereon. A signal receiver mounted in proxmity to the pendulum bob generates an electrical pulse at each pendulum swing. The pendulum swings in a plane having a component parallel to the east-west direction of spin of the Earth. The pendulum has a nominal oscillation frequency at a first aircraft speed with respect to the Earth's surface. The pendulum will have a second oscillation frequency at a second aircraft speed with respect to the Earth's surface due to the change in the Earth's spin-induced centrifugal force on the pendulum. Alternately, the pendulum will have a second oscillation frequency when the aircraft flies over a mass anomaly in the Earth's surface. A frequency discriminator connected to the signal receiver, generates a correction signal in response to changes in the oscillation frequency of the pendulum.

Abstract: By using air speed as an input to a ground proximity warning system that includes: a signal representative of the time rate of change of the aircraft altitude with respect to ground; circuitry for limiting the amplitude of this signal; a signal that represents a time rate of change of the aircraft's barometric altitude; and circuitry for combining the amplitude limited signal, representing the time rate of change of the aircraft with respect to ground, with a signal that represents the aircraft's altitude over ground; the effective warning time is extended by increasing the allowable amplitude, of the signal representing rate of change of the aircraft with respect to the ground, in response to the speed of the aircraft.

Abstract: A system for processing signals representative of airspeed error and inertial longitudinal acceleration of an aircraft to provide an output signal representative of windshear induced acceleration which is filtered to remove the high frequency components and which may be utilized to indicate the presence of windshear to a pilot who can then respond by resetting the thrust to maintain airspeed, or alternatively the output signal is utilized to correct the inertial damping signal of an airspeed control system under windshear conditions.