Abstract: An electrically controlled (16) mechanical actuator (13) is driven by optically generated (23) electrical power through an optically controlled (28) switch (26) in an electrically isolated module (20). Optical transducers (54, 62, 70) and feedback (29), as well as optical inputs (40, 89, etc.) to electrical signal processing equipment (46, 47, 49) in an electrically isolated module (22) dictate the electrical control (28). A helicopter flight control system is wholly digital, with solar remote power and optical intercommunication.

Abstract: An automatic aircraft pitch axis flight stabilization system which does not require the use of a gyroscope is described. Stability signals are derived from an altitude signal responsive to atmospheric pressure. Means responsive to rate of change of altitude produces a vertical rate signal and means responsive to rate of change of vertical rate produces a vertical acceleration signal. The vertical speed signal is combined with a command signal which causes the aircraft to fly at constant altitude, at constant vertical speed, or to descend along a glide slope, and the vertical acceleration signal to produce a control signal which operates a means, such as a servomechanism for positioning the vertical control surfaces of the aircraft.

Abstract: An altimeter code converter that converts a parallel signal of a first code to a serial signal of a second code; The code converter of this invention includes a code conversion means having memory means with an addressable look-up table to convert Gray code to a binary code; a data conversion means having parallel-to-series shift registers connected in series and a flip-flop parity generator for converting the parallel signal to a serial signal; and operably connected to the above means are means for forming and outputting timing and initializing signals.

Abstract: An automatic flight control system for an aircraft having a control surface 28 and including a gyro 12 having an output applied through an attitude filter 14 to the input of a roll rate circuit 16 and a summing amplifier 18. The roll rate circuit 16 generates a rate signal that is applied to a summing amplifier 20 generating a roll rate control signal. The roll rate control signal is input to a roll servo amplifier 22. The servo amplifier 22 combines the rate control signal with a motor velocity signal from a motor velocity detector as part of a roll servomotor 26. Mechanically interconnected to the roll servomotor 26 is the control surface 28 for maneuvering an aircraft about its roll axis. Also, input to the summing amplifier 18 are aircraft command signals from a command block 10 where the authority of such signals is set by a limiter 30.

Abstract: An automatic pilot apparatus, for controlling an aircraft during the execution of a maneuver to capture a predetermined altitude, utilizes an altitude control law formula and signal which define a circular flight path intercepting the predetermined altitude and which result in a normal acceleration force on the aircraft. A signal representative of the normal acceleration force is utilized to generate a predictive pitch command signal which is combined with the control law signal to generate a pitch attitude command signal, thereby allowing the aircraft to smoothly capture the predetermined altitude.

Abstract: During a take-off or missed approach phase of operation the aircraft's maximum barometric altitude is retained in a memory element and compared to the aircraft's current altitude, and if the aircraft's current barometric altitude should be below the maximum altitude by a predetermined amount based on the aircraft's radio altitude, a voice warning is generated indicating that the aircraft is descending. Landing gear and flaps are monitored by the system and if the gear or flaps are down, an additional voice warning is generated indicating that the gear or flaps are down.

Abstract: An automatic flight control system includes an automatic emergency descent mode initiated upon cabin decompression at high altitudes. Automatic safe capture of maximum descent rate and automatic flare to a safe altitude are provided, together with an automatic turn off the course existing at mode initiation.

Abstract: A model aircraft with wireless earth-to-craft control. A device is aboard to emit signals indicating altitude change and visible by the operator on earth, this device being triggered operatively by signals produced by an air-pressure transducer of small size and having low inertia of movable parts.

Abstract: In an aircraft excessive rate of descent warning system that utilizes barometric descent rate compared with aircraft altitude above ground to generate a warning, nuisance warnings at airports having terrain that slopes generally downwardly towards the runway can be substantially reduced by modifying either the descent rate signal or the altitude above ground signal as a function of radio altitude rate thereby having the effect of increasing the descent rate required to trigger a warning when the aircraft is descending essentially parallel to the ground.

Abstract: A performance advisory system which includes a display, a control unit and an onboard computer, the computer receiving inputs from aircraft instruments and gauges and from the control unit and providing advisory output information on the display.

Abstract: A control system for a hydrofoil characterized in that a transition from the foil-borne to the hull-borne mode of operation is initiated and the craft caused to descend or land automatically due to a failure in the primary power source for the control system or some other off-normal condition. The invention constitutes an improvement in prior art systems of this type in that, should the primary power source fail, an auxiliary gyroscope automatically provides stabilization about the roll axis to the unstable craft. This causes the craft to maintain an essentially level deck attitude or, should the craft be in a turn, to roll out of an inclined deck attitude toward a level deck attitude as the craft descends to the hull-borne mode of operation subsequent to primary power source failure. In this manner, the severity of impact with the water as the craft descends during a turning maneuver is reduced.

Abstract: A control system including both a method and apparatus for use on an aircraft during flight utilizes real-time data provided by sensing equipment on the aircraft to iteratively generate values for an efficiency parameter. The aircraft controls are adjusted after each iteration, and successive values of the efficiency parameter are compared until such comparison shows that the parameter has been substantially optimized. Iterations may then continue without corresponding control adjustments until comparison indicates that a current parameter value differs by a predetermined magnitude from the previously determined optimum value, at which time control adjustments resume in order to bring the efficiency parameter to a new substantially optimum parameter value.

Abstract: Terminal guidance of vehicles is accomplished by accurately determining true position and speed of the vehicle from terrain contour measurements and updating a dead reckoning navigation system with precision to permit navigation by following a programmed flight path. A narrow beam radar altitude sensor measures vehicle clearance altitudes and a reference altitude sensor measures the vehicle clearance above a reference level. These measurements are input to a digital processor for comparison to stored digital terrain contour reference data. Recursive data matching is performed in the digital processor by a nonlinear Kalman filtering technique to provide vehicle position and vehicle velocity correction signals to a navigation controller that generates steering commands to the vehicle control system. Three vehicle position and three vehicle velocity signals are generated and updated in the nonlinear Kalman filtering technique to give near real-time three dimensional position and velocity information.

Abstract: A system for generating an optimum vertical speed command and controlling the aircraft to this command by allowing the aircraft to assume an optium trimmed condition for the thrust energy available which system utilizes the aircraft autopilot system.

Abstract: The altitude acquisition and control system cooperates in an aircraft flight controller for permitting a previously selected altitude to be quickly captured without excessive acceleration of the craft normal to the flight path, even though the human pilot may have neglected to arm the automatic capture mode of the apparatus until after the time that the automatic capture mode is normally commanded.

Abstract: Aircraft altitude is maintained through control surfaces responsive to an altitude hold control voltage varying with the output of a pressure transducer. The pressure transducer provides an output varying in a linear relationship with absolute atmospheric pressure and this output is applied to the input of a nonlinear circuit that generates a voltage varying linearly with altitude. A digital-to-analog converter generates an altitude reference voltage in response to an altitude hold engage signal and this voltage is combined in a summing amplifier with the voltage varying linearly with altitude. Also summed with the altitude reference voltage and the voltage varying linearly with altitude in the summing amplifier is a standard reference voltage. The total summation that is made in the summing amplifier produces the altitude hold control voltage as an output thereof.

Abstract: The linear signal output range of a rotary transformer type device, such as a sine/cosine synchro, is considerably extended beyond its normal 45.degree. linear range by electronic circuit means. Specifically, the electronic circuit means utilizes the sine signal, which is generally linear from 0.degree. to 45.degree., as a portion of the output signal and utilizes a resultant signal computed from the cosine signal, which is linear from 45.degree. to approximately 135.degree. for the remaining portion of the output signal.

Abstract: In one exemplar embodiment, a digital altitude encoder is provided that utilizes a conventional altimeter responsive to atmospheric pressure for rotationally driving an indicator shaft. Attached to the shaft is a disc having repetitive, alternate, regularly disposed solid portions and slots. A light source and a pair of light detectors for receiving light from the source are spaced adjacent the disc to permit one of the detectors to generate a first signal and the other detector to generate a second signal having a relative time of occurrence dependent on the direction of the rotation of the disc. A counting means that is presettable to a predetermined digital count representative of a preselected altitude function receives the first and second signals and increments or decrements the predetermined count in response to changes in altitude.

Abstract: A system for developing a warning condition output signal when a monitored input variable exceeds a warn profile defined value defined as a predetermined function of an input reference variable, in which the warning condition output signal is delayed by a time .tau. from the time that a warning condition is sensed. The profile offset thus induced is compensated for by generating an anticipated future value of the reference variable after a time .tau. from the instant value and rate of change thereof, with the anticipated future value being utilized to generate the warn profile. Lag introduced by filtering which might be employed in generating the anticipated value, as well as any lag time existing between a reference variable failure and a failure condition signal which may be used to inhibit development of a warning condition signal, are then permissible, and are compensated for without profile offset by choosing a delay time .tau.

Abstract: A throttle governor/collective pitch control apparatus for radio controlled model helicopters for proportionally controlling either the model helicopter rotor speed or the rotor collective pitch, including sensing and timing means determining the rotor speed and any changes thereof, comparison means for comparing a subsequently sensed rotor speed with a first sensed rotor speed and developing an error signal, and control means responsive to the error signal to provide a control signal proportional to any changes in the rotor speed. In the throttle governor mode any variations in rotor speed result in a proportional control signal to vary the model helicopter throttle so as to maintain constant rotor speed. In the auto-collective mode changes in rotor speed result in a proportional control signal coupled to the collective pitch servo for proportionally varying the model helicopter collective pitch.

Abstract: In an aircraft ground proximity warning system that compares the rate of descent of an aircraft with its altitude above the terrain and in response thereto generates a warning signal when the aircraft's sink rate exceeds a predetermined limit for a particular altitude, a first type of advisory voice warning is generated for combinations of lesser descent rates and greater altitudes and a second type of imperative voice warning is generated for greater sink rates at lower altitudes where the danger of the aircraft impact with the terrain is more significant. In addition, the repetition rate of the advisory warning is increased as a function of increasing descent rate and the amplitude of the advisory warning can similarly be increased as function of increasing descent rate in order to call attention to an increasing undesirable operating condition.

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 constant altitude auto pilot circuit samples an altitude electronically d produces error output voltages proportional to the changes in altitude which are used to command the control system of an aircraft. To set the device, the plane obtains the desired altitude whereafter the device is activated. A switch in parallel with an op-amp is closed to charge a capacitor to a voltage level proportional to the output of a transducer. When the switch is opened, all inputs to the op-amp become relative to the charge of the capacitor. Any variation is amplified by the op-amp. Additional inputs allow biasing the altitude signal up or down or introducing a damping signal for control loop stability.

Abstract: A system for generating an optimum vertical speed command and controlling the aircraft to this command by allowing the aircraft to assume an optimum trimmed condition for the thrust energy available which system utilizes the aircraft autopilot system.

Abstract: In a helicopter having an automatic pilot system for controlling the main rotor collective pitch, main rotor longitudinal and lateral cyclic pitch, and tail rotor collective pitch, in response to inputs provided from normal sensors, navigational instruments and controls, (which include among others as is known, doppler radar, a pilot panel, an air speed indicator, a radar altimeter, a barometric altimeter and a longitudinal accelerometer), commands to control automatic approach to a desired hover position are provided to the autopilot system in response to signals normally supplied by a TACNAV unit as well as the sensors, navigational units and controls; controls are provided for altitude and rate of descent, so as to terminate in hover at a desired altitude, as well as for turns, courses, and speed so as to approach the desired point of hover upwind and to decelerate in a controlled fashion to hover.

Abstract: By utilizing a radio altimeter in conjunction with a measure of the aircraft speed, landing gear position and flap position, an aircraft terrain warning system is made possible which provides a voice warning indicating that the aircraft is too low with respect to the terrain when the aircraft is above a predetermined speed. For aircraft speeds below the predetermined speed, a voice warning is provided when the aircraft is below a predetermined altitude with the landing gear up indicating that the aircraft is too low with the gear up and when the gear is down and the flaps are not in a landing position and the aircraft descends below a second predetermined altitude a voice warning is generated indicating that the aircraft is too low with flaps up.

Abstract: To prevent inadvertent ground contact of the tail of a helicopter during a landing operation without providing a continuous warning signal for normal landings the altitude and attitude signals are scaled such that when they are equal and opposite in voltage and phase compared to a ground contact curve the comparator will energize a relay for actuating a pilot warning signal. A rate of descent signal biases the altitude signal upward varying in proportion to rate of descent as to enable the pilot to have sufficient warning time to take corrective action.

Abstract: In the vertical path control of an area navigation system when the aircraft ascends or descends to a waypoint with an "at-or-above" or "at-or-below" altitude requirement, vertical steering is effected at a constant airspeed with regard to a reference airspeed. An alert device is included to provide a warning to the pilot when the aircraft flight path angle is less than the straight line flight path angle to the waypoint for "at-or-above" waypoints or when the flight path angle of the aircraft is greater than the straight line flight path angle to the waypoint for waypoints with an "at-or-below" altitude requirement. Altitude error is displayed on a vertical deviation indicator of an aircraft flight instrument in accordance with the difference between the actual aircraft altitude and the altitude of the next waypoint having a firm altitude requirement.

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: Apparatus for use with an area navigation system wherein the craft is maintained on a predetermined vertical flight path. Specifically, a pitch command signal for controlling the vertical flight of the craft, which is substantially free of discontinuities, is produced by summing a signal indicative of the vertical displacement of the craft from the flight path with a damping signal representative of the vertical deviation rate of the craft from the vertical velocity required to maintain the craft on the flight path. Additionally, the vertical displacement signal is limited to a maximum amplitude to compensate for discontinuities therein, with respect to passage of the craft through the vicinity of a VOR/TAC station.

Abstract: In an aircraft terrain warning system utilizing a radar altimeter wherein the rate of closure to the terrain is compared with the aircraft's altitude above the terrain to generate a warning signal when the closure rate is excessive for a particular altitude, the closure rate signal is limited and biased depending upon the aircraft's closure rate and configuration in order to significantly increase the time response of the system while at the same time reducing nuisance warnings. The amplitude limit on the closure rate signal is varied, above a predefined altitude, as a function of the closure rate signal in order to provide increased warning times at greater closure rates. Circuitry, responsive to the aircraft's flap positions, is also provided to alter the characteristics of rate limiter so as to provide warning parameters that more accurately reflect operating conditions at lower aircraft speeds.

Abstract: A pressure altitude signal actuates a servomotor coupled through a gear train to an altimeter that includes a rotational shaft for repositioning an aneroid pickoff. Mounted on the rotational shaft is an encoding disc with seven code formations supported on one face of the disc. Each code formation has a generally circular configuration with the various formations juxtapositioned. Six brush pickoffs respond to the six outermost code formations to provide pulse trains related to altitude pressure. A seventh brush pickoff provides a reference code to encoder logic that generates three additional pulse trains related to altitude pressure. The pulse trains of the outer six code formations and the pulse trains from the encoder logic uniquely identify by means of a code bit pattern an altitude.