Patent GB-817442-A (GB)
Title: Improvements in and relating to flight simulating training apparatus
IPC: G09B9/18
Filed: 1955-07-05
Abstract: 817,442. Aircraft simulators. CURTIS-WRIGHT CORPORATION. July 5, 1955 [July 22, 1954], No. 19449/55. Class 4. Apparatus for simulating the propeller synchronizing system in a multi-engined aircraft comprises a master control lever 24 for controlling the speed of all engines simultaneously, a toggle switch for each engine for controlling same individually (shown in Fig. 1 as 33 for engine No. 3), a synchronizing switch 40 for turning a synchronizing system on or off and for selecting a master engine with which the other engines are synchronized as slave engines and a re-synchronizing button 69, Fig. 2 (not shown), whereby individual engines that have run out of synchronization may be brought back to a correct speed. The speed of all engines may be changed simultaneously by master control lever 24 providing the synchronizing system is turned on at the simulated switch 40 and the various engines may be controlled individually by the respective simulated toggle switches, such as switch 33 for engine No. 3, without affecting the speed of the other engines providing the synchronizing system is turned off at switch 40. A servo system 1 which simulates the operation of governor means in the simulated aircraft for the master engine (selected as engine No. 3) comprises an amplifier 2 and a motor 3 which operates the slider contacts 11, 12 and 601 of potentiometers 4, 5 and 6 respectively. Master speed control lever 24 is first operated to move a slider contact 26 on a card 27 to supply a voltage over line 28 and amplifier 29 to the primary winding of a transformer 23. The secondary winding of the transformer supplies a voltage representing a selected r.p.m. for the master engine over line 22, contact 21b and line 20 to amplifier 2 of servo 1. A toggle switch 33 for controlling engine No: 3 operates contact arms 32, 34 and 35, contact arm 32 in the neutral position of switch 33 connecting a positive voltage +E (d.c.) with a relay coil 21<SP>1</SP>, associated with master lever 24, over line 30<SP>1</SP>, the coil, line 30 and contacts a and b of arm 42 operated by a switch 40 which is operated to effect synchronization of all engines. The arm 35 is connected to either a+E or -E voltage by movement of arm 33 and the resulting signal is fed on line 36 to amplifier 2 to represent increase or decrease in the speed of No. 3 engine. Slider 11 of card 4 supplies an answer voltage to amplifier 2 through line 109, contact 108b and line 107 when a relay 21<SP>1</SP> (to be referred to) is energized. Another input to amplifier 2 is picked off card 105 by a slider 104 operated by the motor of a servo 106 controlled by toggle switch 33, the circuit to the amplifier 2 being completed over line 103, contact 102b and line 101 when the relay 21<SP>1</SP> is energised. A further input to amplifier 2 is picked off card 50 by a slider 49 operated by what is referred to as a band-limiting servo 51. Operation of switch 40 to left or right as seen in Fig. 1 completes an engine synchronizing circuit on either engine 2 or 3 respectively to operate a relay 79 associated with servo 106 through contacts 31, 42a or 42b, and 80b, line 81, the relay, line 81<SP>1</SP>, contact 78a, line 82 and camoperated contact 84a and line 87 to a voltage supply +E (d.c.). The cam 85 operating arm 84 is controlled by the r.p.m. servo 86 to close the arm on contact 84a when master control lever 24 selects an engine speed in excess of 400 r.p.m. Below this speed the simulated engine cannot operate so that the circuit remains open on contact 84b. Slider 12 of card 5 operated by servo 1 picks up a signal which is fed over line 600 and contact 601a of a relay 602 to the amplifier of a servo 86 which operates an r.p.m. indicator 603 for engine No. 3. The relay 602 is operated by an instructor to open contacts 601 and 605 to simulate an engine siezure. Card 6 of servo 1 connects at its ends 606 and 607 only with an indicator lamp 609 and slider 601 connects with a +E (d.c.) voltage whereby the lamp gives a trainee an indication of a maximum or minimum governor setting. Between these limits the lamp is not illuminated. A master engine relay 44 is associated with switch 40 so that movement of the switch to the engine No. 2 position energises the relay from a +E (d.c.) source through the relay and line 45 and contacts 43b and 31b to earth. Movement of arms 55 and 56 of the relay complete holding circuits for either servo 1 for engine No. 3 or a similar servo (not shown) for engine No. 2 depending on which servo is selected by switch 40 as the master engine. Relay 92 is referred to as a calibrate relay and relay 93 as a calibrate locking relay switch which is energised when servo 1 corresponds to a maximum governor setting and servo 106 is at zero. Other description and Figures give details of the circuitry for servos 106 and 51 and for a servo for follower engine No. 4 which is similar to the circuitry of servo 1 except that there is no equivalent of master engine relay 44.