Propeller Owner’s Manual
139
DESCRIPTION AND OPERATION
61-00-39
Page 2-20
Rev. 17 Apr/20
CAUTION:
RELEASING THE START LOCKS AT
SIGNIFICANTLY HIGHER THAN 800 RPM
OR AT HIGH RPM CAN CAUSE DAMAGE
TO THE START LOCKS.
Shortly after engine start-up, with the propeller RPM above
800, the latch pins in the start lock units will still retain the
blade angle. To release the latch pins, it is necessary to
manually actuate the propeller slightly toward reverse. This
will move the clamp-mounted plate, allowing the latch pins to
slide freely. Centrifugal force will compress the springs and
disengage the pins from the plate.
Hartzell Propeller Inc. -5 series propellers incorporated
various start lock unit configurations.
(1) Certain three-bladed and four-bladed propellers
incorporate a one-piece spinner mounting plate that is
pinched between the hub and engine flanges. The start
lock units are installed on the spinner bulkhead.
NOTE: The one-piece spinner mounting plate was
superseded by a two-piece spinner mounting
plate on current production propellers.
(2) Current production of four-bladed and five-bladed
propellers incorporate a two-piece spinner mounting
plate that bolts onto the propeller hub flange. The start
lock units are installed onto the spinner mounting plate.
(3) Current production of three-bladed propellers incorporate
a two-piece spinner mounting plate that bolts onto the
propeller hub flange. The start lock units are mounted on
the guide collar.
