| 摘要 |
1,102,781. Measuring electrically. SMITHS INDUSTRIES Ltd. Jan. 14, 1966 [Jan. 20, 1965], No.2464/65. Heading G1N. An aircraft instrument derives a signal representative of the difference between a predetermined value a and the value of the function (α + b#) # being the pitch attitude and α the angle of incidence of the aircraft, and b being a positive constant. This signal is used to indicate how an acceptable flight path can be achieved, for example during an overshoot manoevre. It is stated that the maintenance of a predetermined value a for the quantity α + b# ensures an acceptable flight path. The difference a - (α + b#) may be indicated directly and reduced to zero by alteration of the pitch angle, or may be used to represent a desired rate of change of pitch, (D#) d . The signal (D#) d is passed through a limiter to a summing amplifier where the actual rate of change of pitch is subtracted therefrom, to give an indication of the rate of change of pitch required to achieve the correct flight path, of gradient Y. Alternatively the demanded and actual pitch rates may be separately indicated on an indicator with two moving indices and the aircraft controlled to bring the indices together. In a modified arrangement, in which a - (α + b#) is indicated directly, the indication is provided only when required, by means of a switch, and an arrangement is provided whereby, when the switch is closed, the indication is registered gradually. This system includes a summing amplifier fed directly by the difference signal and also by the voltage on a capacitor charged by the same signal while the switch is open. When the switch is closed the output of the amplifier is zero but rises slowly to the full value of the difference as the capacitor discharges through a resistor. The switch may be actuated automatically in response to a sudden opening of the engine throttles. The value of constant a may be varied in both embodiments in accordance with the setting of the flaps of the aircraft. The value of the pitch-up demand signal (D #) may be increased at the beginning of an overshoot manoevre by injecting a transient signal to boost the value of a and then reducing this signal exponentially to zero. The device may be used to control the aircraft automatically. |
