MAINTENANCE PRACTICES
61-00-36
Page 6-26
Rev. 2 Feb/17
Propeller Owner's Manual
136
D. Placement of Balance Weights for Dynamic Balance
(1) The preferred method of attachment of dynamic balance
weights is to add the weights to the spinner bulkhead.
NOTE: Many spinner bulkheads have factory installed
self-locking nut plates provided for this purpose.
(2) If the location of static balance weights has not been
altered, subsequent removal of the dynamic balance
weights will return the propeller to its original static
balance condition.
(3) Use only stainless or plated steel washers as dynamic
balance weights on the spinner bulkhead.
(4) A maximum of six AN970 style washers weighing up to
approximately 1.0 ounce (28.0 g) may be installed at any
one location.
NOTE: The dimensions of an AN970 washer are:
ID 0.203 inch (5.16 mm), OD 0.875 inch
(22.23 mm), and thickness 0.063 inch (1.59 mm).
(5) Install weights using aircraft quality #10-32 or AN-3( ) type
screws or bolts.
(6) Balance weight screws attached to the spinner bulkhead
must protrude through the self-locking nuts or nut plates a
minimum of one thread and a maximum of four threads.
CAUTION:
IF REFLECTIVE TAPE IS USED FOR
DYNAMIC BALANCING, REMOVE THE
TAPE IMMEDIATELY UPON COMPLETION.
TAPE THAT REMAINS ON THE BLADE WILL
PERMIT MOISTURE TO COLLECT UNDER
THE TAPE AND CAUSE CORROSION THAT
CAN PERMANENTLY DAMAGE THE BLADE.
(7) Unless otherwise specified by the engine or airframe
manufacturer, Hartzell Propeller Inc. recommends that
the propeller be dynamically balanced to a reading of
0.2 IPS, or less.
(8) If reflective tape is used for dynamic balancing, remove
the tape immediately after balancing is completed.
(9) Make a record in the propeller logbook of the number
and location of dynamic balance weights, and static
balance weights if they have been reconfigured.
