LANCASTER I, III & X

MAIN SERVICES

11. Hydraulic system

(i) Each turret b operated by an individual engine-driven pump.

Port outer.........Tail turret.

Starboard inner ...... Front turret.

Starboard outer ...... Mid-upper turret (except on Lancaster VII where the mid-upper turret is electrically operated.)

(ii) Two pumps (one on each inboard engine), with a hand-pump as an alternative, charge a small accumulator and operate:

Undercarriage

Flaps

Bomb doors

Carburettor air intake shutters

Fuel jettisoning

Owing to the large capacity of the flap and undercarriage jacks, it is not normally possible to operate them by the hand-pump in the time available in an emergency.

12. Pneumatic system

(i) A compressor on the starboard inner engine charges an air bottle and operates:

Wheel brakes

Radiator shutters

Supercharger rams (on all aircraft except early Lancaster I)

Idle cut-off rams (on Lancaster III and X aircraft only)

The air bottle charges to 300 lb./sq.in. except when Lincoln type undercarriage is fitted (Mod. 1195) when the bottle charges to 450 lb./sq.in.

A pressure-maintaining valve in the supply line from the air bottle only allows pressure to be applied to the radiator shutters, superchargers und idle cut-off rims, if the pressure in the air bottle exceeds 130 lb./sq.in. (160 lb./sq.in. when Mod. 1195 is fitted). This is to ensure sufficient pressure for the brakes, which operate at 80 lb./sq.in. (125 lb./sq.in. when Mod. 1195 is fitted). It is necessary therefore to check on the triple pressure gauge that pressure is sufficient before 5 ratio is engaged, or radiator override switches or idle cut-off controls are operated.

(ii) A vacuum pump is fitted on each inboard engine, one for operating the instruments on the instrument flying panel, and the other for operating me gyros of the Mark XIV bombsight; the change-over cock (17) is on the right of the instrument panel beside ihc suction gauge (23), and in the event of failure of the vacuum pump supplying the flying instruments the changeover cock can be used to connect the serviceable pump with the flying instruments and cut out the bombsight. It is not possible to operate flying instruments and bombsight on one vacuum pump.

(iii) A compressor fitted on the por inboard engine operates the Mark IV or Mark VIII Automate Pilot, and the computer unit of the Mark XIV bombsight. For operation of the Mark XIV bombsight, the automatic pilot control cock must be set to OUT except on those aircraft in which Mod. 1161 ii incorporated.

13. Electrical system. — Two 1.500 w. generators are fitted on all aircraft except Lancaster VII which have two 3,000 w. generators. The generators are fitted one on each inboard engine and connected in parallel, charge the aircraft butteries (24 volt) and supply the usual lighting and other services including

Propeller feathering pumps

Flaps and undercarriage indicators

Pressure head heating

Fuel booster pumps

Radio equipment

Landing lamps

Engine starting and booster coils

Dinghy inflation

Controls for radiator shutter and supercharger gear-change rams

Controls for idle cut-off rams (on Lancaster III and X aircraft).

Mid-upper turret (on Lancaster VII aircraft).

Bomb gear and bombsight

Fire-extinguishers

Fuel contents gauges

Fuel preasure warning lights or gauges

Camera

Heated clothing

DR compass

An alternator may be fitted to each outboard engine, to supply any special radio equipment.

A ground/flight switch on the starboard side of the fuselage, immediately aft of the front spar, isolates the aircraft batteries when the aircraft is parked or when using a ground starter battery. Two generator switches are provided on the electrical control panel.

AIRCRAFT CONTROLS

14. Trimming tabs. — The elevator (62), rudder (63) and aileron (61) tab controls (on the right of the pilot's seat) all operate in the natural sense and each has an indicator.

14A. Automatic pilot. — On early aircraft the Mark IV Automatic Pilot, and on later aircraft the Mark VIII Automatic Pilot,is fitted, driven by a compressor on the port inboard engine. See A.P. 2095 for operation, which is normal except on some aircraft in which Mod. 1161 is incorporated, when a stop is provided to prevent the control cock from being moved from the SPIN to the OUT position.

15. Undercarriage control. — The undercarriage lever (64) is locked in the DOWN position by a safety bolt (65) which has to be held aside in order to raise the lever. The bolt engages automatically when the lever is set down. The undercarriage may be lowered in on emergency by compressed air (see Part IV, para. 56).

Warning — There is no automatic lock to prevent the undercarriage being raised by mistake when the aircraft is on the ground.

16. Undercarriage indicator (39).— On Lancaster I and III the indicators show as follows:

Undercarriage locked down: Two green lights

Undercarriage unlocked: Two red lights

Undercarriage locked up: No lights

The indicator switch (4) is interlocked so that it must be on when the port engine ignition switches are on. An auxiliary set of green lights can be brought into operation by pressing the central knob if failure of the main set is suspected. The red lamps are duplicated so that failure of one lamp does not affect the indication of undercarriage unlocked. The lights can be dimmed by turning the central knob. On Lancaster X a pictorial type of indicator is fitted. When the indicator switch is on and electrical power is available, the pictorial indicator shows the position of the undercarriage vheels and wing flaps at all times. The disappearance of small red flags shows when the wheels are locked up or down.

17. Undercarriage warning born. - The horn sounds if cither inboard throttle is closed when the undercarriage is not locked down. The outboard throttles do not operate the horn. A testing pushbutton and lamp are behind the pilot's seat, on the cockpit port rail.

18. Flaps control. — If the flaps have been selected partly down, and it it desired to lower them fully, it may be found that the flaps will not lower further for some considerable time. This is due to the pressure in the accumulator having fallen below the pressure required to operate the flaps, bat not sufliciently to cause the hydraulic pumps to cut in. To overcome this, move the flaps selector (60) to UP, and then immediately put it fully DOWN; this causes the hydraulic pumps to cut in. After the flaps have been selected fully down for landirg, the flaps selector (60) should be left DOWN until landing a complete, to avoid any possibility of the flaps creeping up.

On Lancasters I and III the flaps position indicator (26) is switched on by a separate switch (27).

In an emergency the flaps may be lowered by compressed air after lowering the undercarriage (see para. 57).

19. Bomb doors. — The control (43) has two positions only. The bomb release system is rendered operative soon after the doors begin to open and before they are fully open. The position of the doors must therefore be checked visually before releasing bombs. If the bomb doors open only part way and then stop, it is probably due to icing around the hinges and joints, which raises the hydraulic pressure sufficiently to bring the cut-out into operation, which stops any further movement of the doors. If the bomb doors selector is moved to SHUT and then immediately to OPEN, the doors will usually open further; it may be necessary to repeat this several times to get the doors fully open.

As strenuous pumping for 15 minutes is reouired to open the doors with engines stopped, they should be opened before stopping engines if the aircraft is to be bombed up before the next flight.

For emergency operation of bomb doors by compressed air, see Part IV, para. 58.

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