Having seen Clive Calef's beautifully smooth Piccolo in action at an indoor meet at Potters Bar, I realised my own Piccolo was vibrating excessively. I set about curing the imbalance and was amazed at the improvement. The smoothness allowed me to start doing nose-in flying in the living room.
The first stage is to find the source of the vibration. This can be done using a process of elimination:
To balance the main blades properly, you need to balance both statically and dynamically. The technique I adopted does not need weighing scales and although it is not perfectly accurate it made a worthwhile improvement.
The CG of the two blades combined must lie at the centre of the hub in order to balance out centrifugal forces.
Dynamic balancing requires CG of the blades to match each other. Dynamic balance ensures that when the blades bend upwards under load, the centrifugal force of each blade is acting at the same vertical position on the rotor shaft.
Adjustment of Dynamic balance will affect static balance, so you will need to repeat each set of adjustments.
Rotor Head Distortion
On my unit there is a distortion in the rotor head moulding which means that the angle of attack of one blades is about three degrees out. This came as some surprise! Check yours by laying a straight edge under the blade mounting pad, and see if it lines up with the flybar. If not, shim up at the hub as necessary.
If after all the above have been checked and there is still excessive vibration, check that the tracking is not grossly out. Place pieces of tape of different colours on each tip to identify the "high" blade.
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