Two generators drive the 28v electrical system on the number 2 and 3 engines. This system operates the lights, internal and external, instruments, radios, intercom and navigation aids. It is backed up by four 24v batteries located behind the front spar.
Two hydraulic pumps fitted to the inboard engines operate the hydraulic system. Pipework from the two pumps runs to the hydraulic reservoir situated to the rear of the front spar, to an accumulator and an automatic cut-out valve which regulates the hydraulic pressure to around 850psi. This system operates the undercarriage, the bomb doors and the flaps.
A selector valve on the right-hand side of the pilot's seat operates the undercarriage system. This selector is always in either the UP or DOWN position. When a selection is made fluid is delivered under pressure through the selector to the undercarriage jacks.
The bomb doors are controlled by a similar selector valve positioned on the left-hand side of the pilot's seat. When the lever is pushed down the doors open and when it is pulled up they close. The doors are operated by four hydraulic jacks, one at the front and one at the rear of each door.
A single-cylinder jack, mounted in the fuselage behind the rear spar, operates the flaps. The piston rod of this jack extends outwards through both end covers; these are then connected by universal jointed links to push-pull tubes, sliding in bushes, in the trailing edge of the mainplane. A series of short links then connects the flaps to the push-pull tubes. A handle to the right of the pilot's seat, and a control valve mounted below the pilot's floor, govern the raising and lowering of the flaps. This unit has a neutral position, at which the handle is normally set. When the handle is moved to the down position oil is supplied to the downside of the jack so the flaps go down. After reaching the required position the handle is returned to neutral, thereby stopping the flow of oil.
The pneumatic system is operated by two Heyward compressors, which are fitted to the inboard engines. These supply pressure through a pressure-regulating valve, set at 450psi, to an air bottle situated behind the nose turret. This system operates the brakes and the radiator flaps.
A lever on the pilot and co-pilot's control column operates the brakes. This lever is cable-linked to the brake control valve and, when applied, air from the brake control valve inflates the brake bags to 120psi.
The pilot and the co-pilot operate all the flying controls. These include: ailerons, elevators, rudders, aileron trim, elevator trim, rudder trim and flaps. The ailerons are operated by a series of cable, chains, tie-rods and control tubes. The system runs along the port side of the fuselage and at the rear wing centre section it enters the port and starboard mainplanes, where it connects to the aileron outer wing bell crank. From there it travels to the aileron input rod and onto the aileron, which is a metal framework covered with Irish linen.
The elevator and rudder are operated by control rods that run down the port side of the fuselage to the tailplane where they connect to the controls, which are of metal construction.
All the trim systems are cable-operated (5cwt) to a screw jack, which then connects via an operating rod to the trim tabs.
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