Chopperlover said:
I was one of those whose belief was to never touch the product balance whatsoever unless there's been a blade replacement or a repair on a blade.
If that was the case then the maintenance manual would have indicated such stipulations. This is a common misnomer, mainly started due to the fact it takes a bit more work to make these adjustments over trim tabs, hub weights and pcl's.
In the initial mode, product balance is used to reduce the track change between ground and hover. Just like it would be done on a whirl tower.
In the flight mode, product balance is used to reduce vibration, mainly f/a, in hover and the slower forward speeds.
An aircraft in good product balance will also exhibit less issues with the ride quality changing with gross weight or altitude.
Chuck