Aviation of WWII
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Pilot`s Notes Lancaster Pilot`s Notes



Air Ministry, May 1944


75. Oil system. — A self-scaling oil tank is fitted in each nacelle; the normal capacity is 37½ gallons with 4½ gallons air space. A stack pipe in each tank retains 2-3 gallons for feathering the propeller. Normal high-pressure oil feeds the propeller constant speed unit.

Under cruising conditions, it is recommended that the oil temperature should not exceed 60°C, but up to 90°C may be used without damage to the engine. The oil consumption should be between 8 and 16 pints per hour.

76. Coolant system

A horse-shoe type header tank, filled with 30% Glycol and 70% distilled water, is mounted over the reduction gear of each engine. On the ground with engine running a small coolant discharge is normal, but not in flight. From B block on each inboard engine coolant is led to the cabin heating radiator, through which the flow of air is regulated by controls either side of the fuselage at the wireless operators station.

On later aircraft there are two radiators, one for the forward cabins regulated by a control forward of the front spar on the starboard side, and one for the rear part of the aircraft regulated by a control aft of the rear spar on the starboard side.

77. Hydraulic systems

The accumulator, supplied by two pumps, has an air charging valve and a pressure gauge which should read 220 lb./sq.in. when there is no pressure in the system.

Misleading pressure gauge readings will occur if the accumulator air pressure is incorrect. The gauge should read between 800-900 lb./sq.in. under working pressure when the cut-out operates, isolating the pumps. The accumulator then provides the initial pressure to operate the various system. When the pressure falls between 220-300 lb./sq.in. the pumps will automatically be cut in to operate the system and build up accumulator pressure again.

Fuel jettison.—When the fuel jettison control is operated an air inlet valve is opened in the top of each No. I tank, and at the same time a valve is opened at the bottom of each tank, breaking 1 small washer and releasing a spring-loaded stocking. Do not jettison below 100 gallons (set para. 60).

The valves may be closed at any point, but the stocking will not be retracted. When repacking, ensure that the stocking is dry and serviceable. Reseat the inlet and outlet valves. Before fitting one of the spare shear washers carried in the housing, the spindle must pass centrally through the jettison valve.

78. Pneumatic system

The pressure (normally 300-320 lb./sq.in.) is controlled by a pressure regulatng valve, which recommences charging when the pressure drops to 270-280 lb./sq.in. If the pressure drops to 130 lb./sq.in. or below, a pressure-maintaining valve closes, rendering the entire pneumatic system, with the exception of the brakes, out of operation. Therefore M supercharger ratio will be engaged, and the idle cut-off and radiator flaps will be in-operative. If pressure cannot bo built up to stop Merlir 28, 38 or 224 engines, throttle down to minimum r.p.m. and close the master fuel cocks. This will drain the carburettor, which should be carefully primed to expel all the air from the fuel chambers before re-startin. (see para. 42(vi)).

When Mod. 1195 - (incorporating the "Lincoln" type undercarriage) has been fitted, the air supply pressure is increased to 450 lb./sq. in., the pressure regulating valve permits re-charging when the pressure drops to 390-410 lb./sq. in., and the pressure regulating valve doses when pressure drops to 130 lb./sq. in.

79 Electrical system

Four accumulators, connected in series parallel, giving a capacity of 80 ampere hours at 24 volts, are charged by two generators. Two ammeters on the main electrical control panel indicate the total generator output to services and battery charging. On the same panel a voltmeter indicates the state of the accumulators, reading 28-29 volts in flight under normal conditions and over 24 on the ground with engines stopped. On Lancastcrs I and III, spare fuses and a fuse location table are inside the hinged door. The main generator fuses are at the top inside the main control panel. Spare fuses are carried in the lid of the fuse box.

The switches below are for ground fault tracing and must be left on and not touched in flight. On the front of the panel are two earth warning lights, a resin light switch (locked to prevent its movement) and the air bomber's station light switch of which the push button is for use on the ground in conjunction with the earth warning lights.

On Lancaster X, overload switches are fitted in the heavier circuits and flick off if the current becomes too great. Allow five or ten minutes for the service to cool down and turn the switch on.

80. Undercarriage failure

Should the red warning lights remain steady or the green lights not appear when the undercarriage is selected down, operate the warning light changeover switch. If this is ineffective select undercarriage up and return the selector down. If this is still ineffective check the accumulator pressure gauge reading. Should it be 300 lb./sq.in. there is probably no pressure in the system. Select the undercarriage up and down again. The pressure may drop between 200 and 300 lb./sq.in. then rise between 850 and 900 lb./sq.in. when the cut-out operates. If about 800 lb./sq.in. it indicated and the undercarriage appears to be down visually the indicator is probably faulty. If there is still some doubt use the emergency air pressure to make certain the undercarriage is down, turning the cock oft when the operation is complete. This conserves the air pressure for further use; if it is necessary to use the flaps emergency system the method of operation is described in para. 57.

81. Gauges. — The gauges on the engineer's panel in the Lancaster X are the four point type fitting into sockets and are therefore interchangeable.