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: A horizontal situation indicator having a heading card direct-driven by a directional gyro is provided. Relative positioning of the heading card and one or more navigation indicators is determined by sensing an electrical differential between a transducer associated with a heading card and a transducer associated with each navigation indicator. Spring-loaded clutch mechanisms are provided to allow adjustment of the navigation indicators without applying a torque to the heading card and gyro.

Abstract: A signal varying over a wide dynamic range from a source (10) is input to a summing amplifier (12) along with the output of an adjustable reference generator (14). An error signal output of the summing amplifier (12), a subtraction of the output of the reference generator (14) from the input signal source (10), is applied to a rate network consisting of a capacitor (16) and a resistor (18), with the latter in a feedback loop for an amplifier (20). The output of the reference generator (14) is adjusted to maintain the error signal within the operating limits of the summing amplifier (12) by monitoring the output of the amplifier. During the time interval when the adjustment of the generator (14) is made, a compensating network (24) maintains the output of the amplifier (20) at the level previous to the adjustment interval. This provides a continuous output voltage at a terminal (22) that varies over an expanded range with reference to the input signal.

Abstract: A pressure responsive system includes a piezoresistive transducer (10) mounted in a housing (20) with the temperature of the housing and the transducer maintained by heater (22). Operating characteristics of the transducer (10) are normalized by a normalization circuit (18) that interconnects the output of the transducer to a heater control (24). The heater control (24) generates a control signal to the heater (22). A signal varying with pressure is output from the normalization circuit (18) and applied to a DC stabilized gain stage (26) that is corrected for zero signal error and produces an amplification of the transducer output for application to a function generator (12). The function generator (12) converts an absolute pressure signal from the transducer (10) into a signal varying with pressure altitude for utilization in an autopilot system.

Abstract: An automatic pitch trim system responds to the output of a torque detector (34) to provide an input signal to a gain normalization circuit (36). A limiter (38) responds to the gain normalization circuit (36) to produce a limited authority trim signal to a summing amplifier (48). Also connected to the normalization circuit (36) is a window generator (42) that responds to the input signal to activate a time delay (46). The time delay (46) generates a control signal to a signal gate (40) having an input connected to the normalization circuit (36). Under the control of the time delay (46), the output of the mormalization circuit (36) is gated through to the summing amplifier (48) to be combined with the output of the limiter (38) into a signal that is applied to a trim servo amplifier (50). The servo amplifier (50) generates an energizing voltage for driving a trim servo motor (44) coupled to trim tabs (52).

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: Aircraft altitude is visually displayed at a front panel of a flight instrument in analog form by a rotating pointer and in digital form by means of a rotary drum digital indicator. Barometric pressure is converted into rectilinear motion to drive a mechanical-to-electrical transducer providing a signal to a servo amplifier having an output coupled to a servomotor. The servomotor drives both the rotating pointer and the rotary drum digital indicator. Also coupled to the mechanical-to-electrical transducer is a manually adjustable set input signal to correct for atmospheric pressure along a given flight path with respect to sea level. Temperature and altitude error corrections are also coupled to the transducer to correct the servomotor drive signal to give a true indicated altitude display. Also driven by the servomotor is a pressure altitude encoder for providing absolute altitude digital signals for transmission to a ground station.

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.

Abstract: Aircraft altitude is visually displayed at a front panel of a flight instrument in analog form by a rotating pointer and in digital form by means of a rotary drum digital indicator. Barometric pressure is converted into rectilinear motion to drive a mechanical-to-electrical transducer providing a signal to a servo amplifier having an output coupled to a servomotor. The servomotor drives both the rotating pointer and the rotary drum digital indicator. Also coupled to the mechanical-to-electrical transducer is a manually adjustable set input signal to correct for atmospheric pressure along a given flight path with respect to sea level. Temperature and altitude error corrections are also coupled to the transducer to correct the servomotor drive signal to give a true indicated altitude display. Also driven by the servomotor is a pressure altitude encoder for providing absolute altitude digital signals for transmission to a ground station.

Abstract: A system for electrically actuating the pitch trim of an aircraft in both autopilot and manual modes includes a primary pitch servomotor coupled to a primary control surface and a pitch trim servomotor for actuating a trim control surface. In the autopilot mode, an electrical signal applied to the primary pitch servomotor by the autopilot is also applied to two channels of a trim controller providing complementary output signals applied to the pitch trim servomotor. Each channel of the trim controller includes a voltage translator for providing a single ended voltage applied to an integrator that generates an output varying with the time average of the electrical signal applied to the primary pitch servomotor. This time average signal as generated in each channel is chopped into an alternating current signal for driving an output stage. The chopping duty cycle of each channel is varied in accordance with the absolute value of a time average of the electrical signal applied to the primary pitch servomotor.