Patent GB-841566-A (GB)
Title: Equipment for planning the loading of cargo aircraft
IPC: G06G7/70
Filed: 1956-07-25
Abstract: 841,566. Computer for planning loading of aircraft. CONTINENTAL ELECTROLOG CORPORATION. July 25, 1956 [July 25,1955], No. 23034/56. Class 37. The invention comprises means for determining the distribution of cargo into a number of compartments of an aircraft so that the centre of gravity will be in a desired position, such means including an adjustable unit set in accordance with the weight of cargo to be loaded, a second adjustable unit set in accordance with the moment of this cargo, a plurality of units related to a given weight and corresponding moment for each of a sequence of regions of the aircraft, and means controlled by the settings of these units for determining the portion of the cargo to be loaded into the first region of such sequence. Summary. The equipment is basically in three parts :-(1) Manually controlled variable resistors for entering the information, each with associated indicator, (2) automatically balanced Wheatstone bridges for calculating further quantities, some of which are displayed on indicators and obtained as printed records, (3) a timing circuit for connecting the various circuits in the correct sequence and indicator lamps to show the instantaneous state ; this circuit is controlled by manual switches (or automatically in a modification, see below). The information to be entered comprises the following weights and corresponding centre of Gravity positions relative to a datum (e.g. the nose of the craft) :- Basic (aircraft, crew and equipment) ; Fuel ; Cargo to be carried ; Pre-load (already in position before cargo to be planned) ; Planned cargo for each compartment. Since it is uneconomic to load a very small amount into any one compartment provision is made for leaving empty the first and last compartments if necessary. The particular example described is for an aircraft having compartments B to N, of which B, C, D, G and H are available for use. Computing circuits. Fifteen bridges are provided, which perform the following calculations:- B1, predetermined gross moment = (total weight)/(desired C.G. position) ; B2, basic moment = (basic weight) x (basic C.G.) ; B3, fuel moment = (fuel weight) x (fuel C.G.) ; B4, remaining moment = (predetermined gross moment) - (basic moment) - (fuel moment) - (preload moment) - (moments of compartments already planned) ; B5, remaining weight = (total cargo weight) - (preload weight) - (weights of compartments already planned); B6, instantaneous true weight = (basic weight) + (fuel weight) + (preload weight) + (weights of compartments already planned) ; B7, individual compartment weights = (planned weight) x (predetermined C.G.) ; B8, instantaneous C.G. = quotient of sum of moments and sum of weights, the quantities summed referring to basic, fuel, preload and compartments already planned ; B9, "load slope" (SL) = (remaining moment)/ (remaining weight); )B10, (S (#-SL); B11, computed load for next compartment (CL) = (remaining weight) x (S #-SL)/(S #-SC); B12, (S #-SC), where SC = C.G. position for next compartment ; B13, S # = (moments of remaining compartments except the last) / (weights planned for remaining compartments except the last) ; B14, "discriminator", to indicate which of two given quantities is the greater (or also to detect equality, see modification below) ; B15, "load director", which indicates value of CL from B11. These bridges are shown in Figs. 1, 2, 3, 4 and 5, the last two figures being separated since these bridges are connected sequentially into different parts of the circuit, see below. Each bridge has a relay contact between its output and rebalancing motor so that it is not rebalanced until the correct point in the sequence, see below. The "basic", "fuel", and desired take-off weights and C.G. positions are entered by the knobs at the top of Fig. 1, and the estimated weight and known C.G. for each compartment B-N by the knobs in Fig. 2. The knobs X and Y relate to pre-load cargo. Each of the controls in Fig. 2 adds resistance'to bridges B4, B5, B6 and B8 of Fig. 1 and also, when pressed in, operates a switch to connect further resistors to bridge B7 (Fig. 4). A few resistors forming part of bridges B12-B15 are included in the timing circuit diagram described below. Additional controls are (1) a gauged switch 416, 461, 462, 494, 503 (Figs. 6-8) which connects preset resistors representing planned weight and C.G. for each compartment for two different kinds of aircraft, and (2) push buttons B-N (Figs. 6-7) for eliminating particular compartments from the computation if they are not available for loading. Operation. The gauged switch 416 just referred to is set in its appropriate position and the correct values set on the knobs at the top of Fig. 1. Switch S3 (Fig. 10) is put in the "Check" position when voltage is applied from the slider 514 to terminal 516 which energizes the relays of bridges B1-3, and also via the inner ring contact of the switch to contact 256 (Fig. 1) and thence to energize the relay of B6. These bridges are now balanced by their servo motors and their "output" resistors 79, 98, 99, 119, 121 and 208 now represent the corresponding computed values. The manually-set resistors of Fig. 2 which are included in B6 are all at zero at this point so that dial 219 shows the sum of the basic and fuel weights. Switch 584 (Fig. 1) is now closed to energize relay 171 to cut out B6 and energize B8 which then is rebalanced to display the C.G. position on its dial 318. In this particular example of the operation of the equipment it is assumed that compartments B, C, D, G, and H are available for loading, E and F have a pre-load and M and N do not exist. The .last fact is allowed for by the switch 416 (Fig. 7) which energizes relays RL-12 and RL-13 to short-out the corresponding resistors which relate to weight and moment for these compartments. Push-buttons E, F, I, J, K, L are pressed to energize relays RL-4, RL-5 and RL-8 to RL-11 which perform a similar function for compartments E, F, I-L which are not to be loaded. Switch S3 (Fig. 10) is now turned to the "Pre-load" position and the weight and C.G. values of the pre-load cargo set up on knobs X and X<SP>1</SP> in Fig. 2. Pressing of the knob X will connect the appropriate resistors into B7 and effect balance, and consequently B6 will be rebalanced with the extra values of weight ; this will occur throughout the following procedure when values are set up on the knobs B, C, D, G and H. The C.G. bridge B8 is rebalanced later in the sequence, see below. Switch S3 (Fig. 10) is now turned to "B" position ; this energizes relay 541 and starts the timer motor M which rotates the conducting shaft 511 and associated conducting cams C-1 to C-15. Wiper C1 energizes relay 546 and lights "Computing" lamp 572. Relay 546 energizes relay 547, deenergizes 541 but holds the potential on motor M. Relay 547 holds itself on and de-energizes 541. Wiper C2 energizes the relays' of B4 and B5 which are then rebalanced in accordance with remaining moment and remaining weight respectively. Wiper C2 is then disengaged and B 4 and B5 remain in their set positions. The load distribution pattern and corresponding moments for the various compartments are predetermined by the resistors 466 (Figs. 6 and 7), and the resistors corresponding to those compartments whose relays have not been energized, viz : RL-1, RL-2, RL-3, RL-6 and RL-7, will be connected in circuit to terminals T1 and T2 respectively. Wiper C3 now engages and energizes relay 574, completing a circuit from wiper C15 to relays 608 and 610. Wiper C4 completes a circuit via contacts of relays 644, 693, 692 and 691 to energize relay 646 of bridge B14 (Fig. 1). Wiper C5 energizes relay 575 to actuate relay 614 from wiper C15 and apply a potential to terminal T10 which is attached to the discriminator switch contact 639 (Fig. 1). The discriminator bridge B14 is now constituted by four arms:- moment resistor 139 of B4, weight resistor 189 of B5, sum of moment resistors 466 via T1, and sum of weight resistors 466 via T2. The bridge B14 compares the ratio of remaining moment to weight with the ratio of (sum of compartment moments) to (sum of compartment weights). It is here assumed that the former ratio is greater, so that the arm 642 is rotated clockwise and closes the contacts momentarily. A potential is then applied to relay 691 which is energized and lights the "Switch to Next Compartment" lamp 725. Relay 691 holds on, energizes relay 618 and breaks the lead from C4 to the B14 relay, thus stopping the rotation of the servo motor, and rendering ineffective the engagement of wipers C6-C12. Relay 618 connects resistors 698 and 699 to bridge B15, whose relay is energized by relay 583 when wiper C13 engages. B15 is then brought to balance with zero reading on its dial. Wiper C13 is then disengaged and relay 583 falls off. Half-way through the cycle wiper C14 energizes relay 171 (Fig. 1) so that the C.G. bridge is rebalanced for the preload values set by X <SP>1</SP> in the same way as was the weight bridge B6. Wiper C1 is now disengaged, cutting off relay 546, motor M and "Computing" lamp 572. Wiper C15 still however keeps relay 691 energized and "Shift to Next Compartment" lamp 725 on. Switch S3 is therefore turned to position C, and ganged with this are S2 (Fig. 9) on position C, and S1 (Fig. 7) one step behind on position B. Motor M now starts again, C15 de-energizes 691 and lamp 725 goes out. Cl holds the motor circuit, C2 energizes B4 and B5 (which are already balanced), and C3 joins the sum of moment and weight resistors to B14 as before. Contact B on Sl now energizes relay RL-1 so that the resistors corresponding to compartment B are shortcircuited and B14 performs the comparison as before, but for compartments C, D, G, H only. It is now assumed that the ratio of remaining moment to weight is less than the ratio of the sums of the compartment moments and weights. B14 servo moto