Propeller Owner's Manual
115N
DESCRIPTION AND OPERATION
61-00-15
Page 2-31
Rev. 24 Dec/20
5. Aerobatic Accumulator
(Rev. 1)
CAUTION:
THE EFFECTIVENESS OF THE
ACCUMULATOR SYSTEM CANNOT
BE ACCURATELY SPECIFIED DUE
TO VARIABLES IN THE ENGINE AND
GOVERNOR INTERNAL LEAKAGE RATES,
AS WELL AS THE EXTENT AND DURATION
OF OIL STARVATION. THE SYSTEM
CANNOT ENSURE 100% PROTECTION
FROM OVERSPEED IN ALL OPERATING
CONDITIONS.
A. System Overview - Refer to Figure 2-10
(1) The fundamental purpose of the accumulator is to supply
oil to the governor during brief circumstances of engine
oil starvation, not prolonged periods of this condition.
The accumulator's oil supply helps to avoid loss of
propeller control and overspeed.
(2) The accumulator has a one (1) quart capacity for the oil
and the volume required for an air charge. A piston or
diaphragm separates the oil and air.
(3) When the engine is operating, the engine oil system
supplies oil to the input side of the governor gear pump.
The oil supply also charges the accumulator at any
time the engine oil system is developing a pressure
greater than the accumulator air charge pressure. The
accumulator is filled with oil until the air charge pressure
of the compressed air volume is equal to the engine oil
pressure.
(4) In the event that the engine oil pressure drops below the
accumulator air pressure, the oil in the accumulator is
discharged to supply the governor gear pump. A check
valve in an adapter located between the engine and
governor will prevent the accumulator from discharging
oil into the engine. The loss of propeller control and
overspeed are avoided while an oil supply to the
governor is maintained.
