GB637188A - Automatic control apparatus for aircraft - Google Patents

Abstract

637,188. Automatic attitude and steering control systems for aircraft. SMITH & SONS (ENGLAND), Ltd., S., and MEREDITH, F. W. April 28, 1947, No. 11351. [Class 38 (iv)] In aircraft control equipment comprising means for banking the aircraft about a selected angle relative to a roll datum and applying a corresponding rate of turn in azimuth, means including a side-slip detector is provided correcting both the angle of bank and the roll datum upon side-slip occurring due to wander of the roll datum. In Fig. 1, the aircraft is banked about a roll axis 14 by rotating a normally horizontal platform 11 to generate from a roll gyroscope 5 an A.C. voltage proportional to the rate of turning of the platform, this being applied to an aileron servomotor 19 through a high gain amplifier 21 in series with an opposing feedback voltage reducing the input substantially to zero from a generator 22 driven by the motor so that the aircraft rolls at a rate and by an amount to maintain the platform horizontal. At the same time a tangent potentiometer 24 applies a signal through a similar system to the rudder, servomotor causing the aircraft to turn under the applied bank at a rate such that the voltage' from a rate-of-yaw gyroscope 1 cancels that of the potentiometer and at normal cruising speed no side slip occurs. At angles of bank above 3 degrees a battery connected wiper arm 54 on the platform gimbal 13 moves from an insulated insert 56 to energize through a contact 55 a relay 51 and operate to dotted position switches 52, 53 so that a pendulum side-slip detector 25 output in series with the yaw gyroscope 1 monitors the rate of turn. Below 3 degrees, however, the insert 56 insulates the arm 54 so that the relay 51 and switches are de-energized and the side slip voltage, if any, is applied in series with the roll circuit to correct the angle of bank. Side-slip due to wander of the bank datum level is therefore prevented. In a modification, the side-slip detector output is applied to the roll control circuit whatever the angle of bank and correction made in the yaw control circuit for varying speeds of the aircraft by varying the output of the tangent potentiometer by a further potentiometer operated by a pitot pressure tube. The generator 22 and electric motor 19 may be of the two-phase hysteresis type described in Specifications 576,248, 576,249 and 576,351 respectively. Specifications 611,037 and 617,240 also are referred to.