The Dynamic Balancing Method
Simply stated; two sensors
attached to the engine provide data to a prop balancing computer during
three brief engine run-ups to 2000-2200rpm. After each engine run-up,
the computer prescribes an increasingly accurate corrective weight
amount and location to balance the entire rotating group. The
weights (AN washers) are temporarily located under one or more spinner screws
or bolted directly to the ring gear on some Lycoming engines. After
the prop generated vibration level is reduced to near zero (usually
after the third engine run-up) the spinner is removed and weights
are permanently installed in
accordance with F.A.A. approved specifications.
The F.A.A. considers Dynamic Prop balancing
to be a minor repair when applied to engines rated under 500HP.
Dynamic Prop Balancing
should be performed after either engine or prop overhaul and checked
again at mid-time. Balance should also be checked whenever the prop is
removed and reinstalled for any reason. If a prop balancing entry can't
be located in the maintenance logs (since the last engine or prop overhaul) it should most definitely be checked
ASAP. The entire
procedure, performed to Doug's exacting standards, takes approximately 2.0
hours.
