application of control wheel force. A force transducer, located in the aileron control quadrant, supplies an output signal proportional to the force applied to the control wheel. The force, applied to the control wheel in excess of detent level, will cause the roll computer to command a rate of change of bank angle proportional to the applied force. When operating CWS, the resolver (RS) feedback is removed by action of switch RS-2 allowing the roll computer to function as an integrator. The roll computer then produces a roll rate command proportional to control wheel force above the detent level.
(b)
The output signal from the CWS force transducer is applied to deadzone amplifier as shown in figure 6. The function of the deadzone amplifier is to produce zero output (deadzone level) for applied forces ranging between approximately 0 and 4 pounds. Above this detent level, the output of the deadzone amplifier is proportional to the force applied to the control wheel. An output of the deadzone amplifier is applied to the CWS detent sensor in the deadzone amplifier. The function of the detent sensor is to detect control wheel force transducer output levels corresponding to those which are above the deadzone level and to activate interlock circuits accordingly. Switch RS-16 increases the threshold detection level of the detent sensor during the on-course phase of lateral radio beam operation and during the heading select mode to prevent nuisance disconnects of these modes. The other output of the deadzone amplifier is applied to a low-pass filter. The function of the low-pass filter is to filter and attenuate control system resonances. Switch RS-17 is paralleled to RS-16 and prevents CWS signals from affecting the autopilot when in on-course or heading select modes. The output of the low-pass filter is applied to summing point 7 and to an amplifier which provides an input to summing point 9.
(c)
The signal at summing point 7 is applied to the bank rate limiter. The bank rate output drives the roll computer up to its maximum rate of 13 degrees per second through the motor amplifier. Bank angle command is limited to 32 degrees by the bank angle stops in the roll computer. When the roll
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computer is driven by the CWS signal, the roll computer CT develops an error signal. This error signal results in aileron displacement as described in roll attitude hold mode. The CWS signal which is amplified and fed directly to summing point 9 provides compensation for velocity error between actual and commanded bank angles. This signal path is blocked by RS-18 when the lateral beam sensor is pulled in. The CWS signal gain and the roll resolver feedback into summing point 7 are switched (RS-8 and RS-2) as a function of LBS dropout, thereby enabling those airplanes with a supervisory override option to use CWS inputs into the roll computer when the airplane is on course.
(4)
Heading Select Mode
(a)
The heading select mode of operation can be selected any time after roll axis engagement except during the CWS mode or after lateral radio beam engagement. The heading select mode is obtained by placing the control panel heading switch to applied to logic OR gate 2. This logic level is applied to AND gate 3 (Fig. 8). An additional power input (28 volts dc from the engage interlock circuit) and a logic input (lateral beam sensor (LBS) not dropped out and control wheel steering not out of detent) operate AND gates G4 and G3 to hold the heading select switch engaged. The normally closed set of contacts of the heading switch open to remove power from a heading select NOT logic circuit and heading computer motor clamp circuit in the roll channel.
(b)
Heading error signals from the heading select synchro in the course deviation indicator (CDI) are applied past de-energized switch RS-5 through a bus synchronizer to summing point 1 of Fig. 6. The bus synchronizer consists of a demodulator-modulator which performs a quadrature rejection function (rejection of extraneous 90-degree components of inphase or out-of-phase signals) and synchronizes the signal with the autopilot reference signal. Heading error signals at summing point 1 are amplified, fed through the heading Q-potentiometer, and then applied to summing point 2. The output signal from the heading Q-potentiometer does not drive the lagged roll integrator since the lagged roll integrator is in a reset condition. The heading error signal at summing point 2 is applied to summing point 7 through the bank angle limiter. The bank angle limiter provides a bank angle command limit of 25 degrees. The limited heading signal is summed with the
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