GB1156017A - Improvements in or relating to Control Systems. - Google Patents

Abstract

1,156,017. Controlling aircraft; aircraft warning indicators. TEDDINGTON AIRCRAFT CONTROLS Ltd. 8 Dec., 1966 [8 Dec., 1965], No. 52034/65. Headings B7G and B7W. [Also in Divisions F2 and G3] A butterfly valve 1 controlling the supply of air from the engine compressor of a VTOL aircraft to stabilizer nozzles is actuated in response to movement of the main thrust nozzle. As shown, the valve 1 is positioned by a doubleacting piston 6 via link 5 and crank 4. The piston chambers 8, 9 are supplied from the duct 2 upstream of valve 1 via filter 18, solenoidoperated valve 20 and lines 11, 12, permanent bleeds 13, 14 being provided for each chamber. Valve 20 includes an armature disc 28 and coils 31-34 arranged in pairs one within another on opposite sides of the armature. Inner coils 32, 34 are connected via switches 46, 47 to terminals 44, 45 of switch 41. The latter is controlled by cam 42 in response to movement of the main thrust nozzle. As shown, the latter would be positioned for normal flight so that switches 41, 47 connect the supply to light lamp 52 to indicate that valve 1 is closed. Air supplied to chamber 8 via port 25 of valve 20 maintains valve 1 closed. When the main nozzle is rotated through 5 to 15 degrees, switch 41 connects the supply to coil 32 via switch 46 and the armature moves to connect the air supply to chamber 9 to open the valve 1. Rotation of spindle 3 causes cam 48 to operate switch 46 to light lamp 51 to indicate valve 1 is open. At the same time, switch 47 connects coil 34 to terminal 45 in preparation for the reverse sequence, i.e. return of the main nozzle to the horizontal. A switch 49 operated by cam 48 lights lamp 50 during movement of valve 1 from one position to another, such movement occurring within an arc of 96 degrees. If the inner coils should fail, a manual switch 53 is used to energize outer coils 31, 33 via switches 55, 56 operated by cam 54 driven by valve 1. The sequence of operations is identical to that described above except that switch 53 is operative instead of switch 41. A pressure switch 19 prevents operation of the valve 20 when the engine speed is below a certain value. In an alternative embodiment (Fig. 2, not shown), the coils and lamps are connected to a negative line instead of being earthed, and switch (19) is connected between the voltage source and switch (53). The coils and lamps are also connected to switch (53) through a rectifier (60). Failure of switch (19) is compensated by operating switch (62). In Fig. 3 (not shown), two pressure switches (71, 72) replace switch 19. Double wound coils may replace the separate coils of each pair and a spring may bias armature 28 to a position causing opening or closure of valve 1.