Hartzell HC-E4 3 Series Owner's Manual page 68

Propeller Owner's Manual
147
When the propeller reaches the desired reverse position,
movement of the beta ring and beta feedback block
assembly initiated by the propeller piston, causes the beta
valve to shut off the flow of oil to the propeller. Any additional
unwanted movement of the propeller toward reverse, or any
movement of the manually positioned beta valve control
toward high pitch position will cause the beta valve to drain
oil from the propeller to increase pitch.
For installations with electronic beta sensors, the propeller
is reversed by manually repositioning the cockpit-control
to cause the PCU to supply oil from the PCU pump to the
propeller. The electronic beta sensor reads the position of
the specially designed beta ring and communicates propeller
blade angle position to the FADEC.
When the propeller reaches the desired reverse position,
the electronic beta sensor determines the movement of the
specially designed beta ring, initiated by propeller piston,
and the FADEC tells the PCU to stop the flow of the oil to
the propeller. Any additional unwanted movement of the
propeller toward reverse, or any movement of the cockpit
control toward the high pitch position will cause the PCU to
drain oil from the propeller to increase pitch.
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DESCRIPTION AND OPERATION
Rev. 17 Sep/20