Abstract: In order to provide a more accurate representation of aircraft pitch attitude for use in aircraft head up display devices, a circuit for generating a computed pitch signal responds to a longitudinal accelerometer and a vertical gyroscope within the aircraft wherein the computed pitch signal is generated by adding to the gyro pitch signal a correction factor computed by subtracting the value of the computed pitch signal from an inertial pitch signal derived from the longitudinal accelerometer. In order to compensate for the effects of aircraft acceleration on the longitudinal accelerometer signal, a computed acceleration signal derived from the difference between the longitudinal accelerometer signal and the gyro pitch signal is subtracted from the longitudinal accelerometer to generate the inertial pitch signal.

Abstract: In order to facilitate construction of a compact, lightweight servoed accelerometer with capacitive pick-off, a one-piece support frame, adapted to be inserted within a cylindrical housing, is used to support a pair of capacitor plates and a lightweight longitudinally reinforced pendulum or seismic mass having a paddle on one end. Attached to the pendulum is an axle which in turn is supported between two flexures by means of jeweled pivoted bearings. Also attached to the pendulum is a torque coil which interacts with a magnetic assembly, secured to the support frame, to restore the paddle to the midpoint between the capacitor plates when the pendulum has been subjected to an acceleration force.

Abstract: An on-axis, optical head-up display device, for use in fixed installations, vehicles or aircraft, utilizes a single block of transparent acrylic resin with the upper surface curved and coated to form a collimating mirror. The block itself is comprised of two major portions cemented together with a transparent bonding material wherein the resulting interface forms a combining surface. A generated image is transmitted from the focal plane of the collimating mirror upwardly through the combining surface; then it is reflected downwardly by the collimating mirror back to the combining surface which in turn serves to combine the generated image with a background view. The combined image is viewed by an observer through a back window of the block. Optical aberrations are reduced by extending the material of the block to the focal plane of the collimating mirror where an image generator is located.

Abstract: To eliminate the high frequency portion of an input signal while permitting low frequency and DC portions to pass, the electronic filter utilizes an n-1 order active network in combination with a capacitor to generate a shunt current, thereby providing a low pass filter having n-order operating characteristics. Included in the active network is an active element, such as an operational amplifier, which responds to an input signal by creating a voltage across the capacitor, resulting in a shunt current that in turn provides the desired filter characteristics. In certain special cases the n-order active filter can utilize a differentiating element in combination with n-2 order active network along with the capacitor to achieve n-order operating characteristics.

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: An aircraft instrument with a reflective screen on which the pilot views a collimated head up display of flight guidance information against a background of the outside world, for low altitude maneuvers. The guidance information includes a pitch stabilized reference indicia and a flight path indicia. The pitch reference and flight path indicia are positioned on the screen in accordance with aircraft operating parameters and pilot inputs to provide for a flare maneuver to touchdown or to direct the pilot in a path parallel with the surface of the ground, as for ejecting cargo.

Abstract: In a recording tape lubricating apparatus, a tape is passed through a plenum chamber having a baffling hood therein which substantially encircles a portion of the length of said tape as a mist of oil is directed toward the underside of said tape under said hood. A film of oil is deposited on the underside of said tape with the surplus mist, in part, condensing on the inside of the hood and dropping to the floor of the plenum chamber where both the condensed oil and the balance of the surplus mist is evacuated to prevent escape into the surrounding facilities.

Abstract: An aircraft instrument for warning the pilot that the aircraft is in an unsafe condition in proximity to the ground. The instrument has inputs representing aircraft configuration, flight condition with respect to the ground, and glide slope. Detector circuits process the inputs and give a warning of unsafe proximity to the ground. The boundary conditions for the warning are selected to avoid false warnings. A glide slope detector distinguishes between a valid glide slope signal and spurious signals, without need for pilot input.

Abstract: An apparatus for lapping the edges of a metal foil tape to remove burrs. A pair of coaxial counter-rotating wheels have facing annular abrasive surfaces which are spaced apart a distance less than the width of the tape. The tape is drawn between the wheels, generally along the wheel diameters, with the tape edges in engagement with the abrasive surfaces. The peripheral velocity of the wheels is substantially greater than the lineal speed of the tape so that the tape edges are polished substantially at right angles to the plane of the tape.

Abstract: A television signal distribution system for special programs in an establishment, as a motel, with plural receivers. A master antenna is connected through a cable distribution system with each of the receivers. Special program signals, as of a movie, are distributed through the cable on an unused channel. A filter at each receiver blocks the special signal from the receiver. A circuit actuated from a central control station is directed to the room over the telephone system and disables the filter enabling the occupant of the room to watch the special program.

Abstract: A collimated head up display of pitch related information for an aircraft operator. A generated pitch signal combines a gyroscope signal referenced to the airframe with an inertial signal referenced to the head up display or combiner screen. A pitch error signal representing the difference between the generated pitch signal and the inertial pitch signal is limited and integrated to develop a pitch correction signal which is added to the gyroscope signal. Reference of the inertial signal to the combiner screen of the display eliminates static alignment errors. The pitch correction signal may be selected for display during alignment of the combiner screen.

Abstract: A Super-8 mm. movie film with two amplitude modulated optical sound tracks, one in each margin of the film. A method for optically recording and reproducing audio information with high fidelity on a very narrow sound track. A scanning apparatus has lens and masks which accurately define and direct a light beam on the film sound track for high fidelity reproduction.

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: 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: For use in an aircraft warning system which measures the descent below a radio glideslope and compares it with the aircraft's altitude above ground to generate a warning when the descent below glideslope exceeds predefined limits for a particular altitude, circuitry is provided to generate an advisory warning above a predefined altitude and a hard warning, or command to take immediate action, below the predetermined altitude.

Abstract: In a system that compares the rate of descent of an aircraft with its altitude above ground and generates a warning signal when the sink rate exceeds a predetermined limit for a particular altitude, the maximum warning time is limited to a specified value in order to minimize nuisance warnings at higher altitudes. At a descent rate above a certain value, the excessive sink rate warning signal is inhibited for combinations of descent rates and aircraft altitudes which would provide a warning greater than a selected time to impact, such as 30 seconds.

Abstract: In a warning system for aircraft that generates a warning signal when the aircraft is descending during a take-off or missed approach phase of operation, the warning is inhibited for a predetermined loss of altitude in order to allow the aircraft to descend a short distance without triggering a nuisance warning. Specifically, a circuit is provided to integrate a signal representing the aircraft's rate of descent until the integrated signal is equal to a predetermined drop in altitude whereupon the warning signal is triggered.

Abstract: An aircraft instrument for warning the pilot that the aircraft is in an unsafe condition in proximity to the ground. The instrument has inputs representing aircraft configuration, flight condition with respect to the ground, and glide slope. Detector circuits process the inputs and give a warning of unsafe proximity to the ground. The boundary conditions for the warning are selected to avoid false warnings. A glide slope detector distinguishes between a valid glide slope signal and spurious signals, without need for pilot input.

Abstract: The warning system includes a function generator for generating a signal representative of a minimum altitude over terrain as a function of the aircraft's speed. This signal is combined with a signal representing the aircraft's actual altitude over the terrain and if the aircraft is below this minimum altitude a warning signal is generated. A circuit is included to inhibit the warning signal, and thereby nuisance warnings, when the aircraft overflys another aircraft. In addition, electronic circuitry is disclosed for implementing the invention that is compatible with at least two separate types of air data computers.

Abstract: An aircraft instrument for warning the pilot that the aircraft is in an unsafe condition in proximity to the ground. The instrument has inputs representing aircraft configuration, flight condition with respect to the ground, and glide slope. Detector circuits process the inputs and give a warning of unsafe proximity to the ground. The boundary conditions for the warning are selected to avoid false warnings. A glide slope detector distinguishes between a valid glide slope signal and spurious signals, without need for pilot input.