Patent GB-781477-A (GB)
Title: Improvements in apparatus for controlling the centre of gravity of a system of inter-connected loads
IPC: B64D37/20
Filed: 1954-08-05
Abstract: 781,477. Electric measuring systems. MINNEAPOLIS - HONEYWELL REGULATOR CO. Aug. 5, 1954 [Aug. 10, 1953], No. 22800/54. Class 37. [Also in Group XXXV] In a system in which the discharge from aircraft fuel tanks is automatically controlled (see Group XXXV) to minimize change in the position of the centre of gravity of the aircraft as a whole, and in which allowance is made for different weights of the aircraft and/or any bombs or supplies dropped en route, meters indicate the quantity of fuel in each tank and the position of the centre of gravity of the aircraft. In Fig. 1, variable capacitance type contents gauges 15, 16, 17 are associated with fuel tanks 10, 11, 12 positioned as shown relative to horizontal axes X, X<SP>1</SP>; Y, Y' in the aircraft. Capacitance 15 applies a voltage dependent on the quantity of fuel in tank 10 from the secondary winding 23 of a transformer 21 to the input of an amplifier 34 the output of which energizes a motor 40 driving a rebalancing potentiometer 30 and a contents indicator 41. A further input to amplifier 34 through a capacitance 36 compensates for stray capacity when the tank is empty. Motor 40 also drives a potentiometer 46 so as to apply through a transformer 55 a voltage dependent on the contents of tank 10. Voltages dependent on the contents of tanks 11 and 12 are derived in a similar manner and applied through transformers 63 and 64 respectively. A further voltage dependent on the weight of the aircraft itself is produced by a manually-operated potentiometer 270. The last-mentioned voltage together with the three contents voltages are applied in the correct senses to an adding circuit 65 the resistances of which are inversely proportional to the distances of the loads from the Y-axis. A voltage dependent on the resultant moment about the Y-axis is thus applied through a transformer 76. A voltage dependent on the resultant moment about the X-axis is derived in a similar manner by an adding circuit 74 and applied through a transformer 282. The three contents voltages are also applied to an adding circuit 85 deriving a voltage representative of the total quantity of fuel. A motor 172 energized from an amplifier 161 operates a pointer 173 to indicate the distance of the centre of gravity of the whole aircraft from the Y-axis since the resultant moment about the Y-axis, represented by a voltage applied to amplifier 161 through a lead 162, is divided by the weight of the aircraft represented by the output voltage of a transformer 282. Division is effected by motor 172 operating a potentiometer 167 across the output of transformer 282 the input to which is the sum of a voltage representing the total quantity of fuel applied through a lead 283 and a voltage representing the weight of the remainder of the aircraft obtained from a manually-operated potentiometer 284. In a similar manner a dividing circuit 160 serves to indicate the distance of the centre of gravity of the whole aircraft from the X-axis. A motor 183 energized by amplifier 175 operates a pointer 192 to indicate the contents of any tank or all tanks according to the position of a selector switch 180. In a modification, Fig. 2 (not shown), voltages introduced into the system corresponding to bomb loads are automatically removed by contacts operated when the bombs are dropped.