Patent GB-659791-A (GB)
Title: Improvements in automatic pilots for aircraft
IPC: G05D1/08
Filed: 1944-04-26
Abstract: 659,791. Automatic control systems for aircraft. SPERRY GYROSCOPE CO., Inc. April 26, 1944, No. 7845. Convention date, April 26, 1943. [Class 38 (iv)] [Also in Group XXIX] Attitude : steering.-In an automatic piloting system for aircraft, right and left control surfaces on the wings are moved in the same direction in response to pitch and in opposite directions in response to roll and/or change in heading of the craft. The systems described are for the automatic piloting of an aircraft of the flying wing type having a single control surface on each wing, and may be separated into two main types, viz.: those in which the outputs of separate signal-producing pickoffs, associated with suitable standards of position and detecting pitch and roll respectively, are combined in two different manners to control each of the control surfaces, and those in which separate pick-offs detect tilt of the aircraft about each of two axes perpendicular to lines joining the centroid of each control surface to the point of intersection of the pitch and roll axes and, in consequence, give two outputs, each responsive to both pitch and roll, to separately control each of the control surfaces. 1st type, Fig. 2. Pitching and rolling of the craft are detected by pick-offs 31 and 32 respectively, associated with standards of position, e.g. gyros 33, 34 and the signals combined in two different manners in a stage 30 to give two outputs operating, through servomotors 28 and 29, right and left control surfaces 24 and 25 on the respective wings to maintain the craft in a predetermined attitude with respect to the pitch and roll axes. Change in heading of the craft is detected by a pickoff 102 associated with an azimuth standard of position 101, this signal being added to or taking the place of the roll signal to maintain a predetermined course, since banking effects turning in azimuth. The pick-offs, which may be electromagnetic or pneumatic, Figs. 4 and 5 (not shown), are manually adjustable by knobs 200, 201, 202 to facilitate course and attitude setting. Manual switches 120, 121 permit disconnection of the azimuth or roll pick-off, such disconnection serving to prevent interference between turn and roll signals while setting controls 200, 202 to effect a banked turn. The following alternative forms of stage 30 are described : (a) Figs. 3, 3A (not shown). Two thermionic-valve controlled electromagnetic torque motors operating hydraulic servomotors in response to pick-off signals as described with reference to Fig. 2 in Specification 612,804, constitute the connecting links between the pitch and roll pickoffs and the control surfaces, mixing being effected by the provision of auxiliary windings on each torque motor connected in series with the main winding of the other torque motor in such a manner that a pitch signal results in movement of the control surfaces in the same direction while a roll or turn signal results in their movement in opposite directions. In the case of combined pitching and rolling one torque motor is responsive to half the sum of the pitch and roll signals and the other to half the difference; (b), Fig. 8 (not shown). Two thermionic-valve controlled, generator-field-controlled, Ward-Leonard-controlled dynamo-electric servomotors constitute the connecting links between the pitch and roll pick-offs and the control surfaces, mixing being effected by the provision of auxiliary thermionic-valve stages intercoupling the main thermionic valve circuits in the appropriate phase to cause operation of the control surfaces as at (a) above. 2nd type, Figs. 9-12 (not shown). Two pick-offs associated with a single standard of position located where the pitch and roll axes meet or one associated with each of two standards located elsewhere, are arranged to give outputs responsive to tilt (combined pitch and roll) about axes perpendicular to lines joining the centroid of the control surface to the point of intersection of the pitch and roll axes, these outputs controlling separately, through suitable servo means, the two control surfaces. For the case in which two standards of position are employed suitable gearing is described to enable single knobs to set manually, the angle of elevation and bank respectively.