"However, your point about the balance of the MGB running without the big lump of metal welded to the bottom of the main shaft is, I think, important, and something EC needs to address in their testing."
If you look inside an actual gearbox at the relative size and mass of the main rotor shaft versus the bevel oil pump drive shaft, you will see that the analogy of "elephant vs mouse" would be apposite.
Furthermore, once the bevel shaft has dropped off the main shaft, there is no possibility of an imbalance arising, because the two shafts were centred on the same vertical axis before parting company.
It's about the same relationship in terms of vibrational consequences, as if a hub-cap dropped off your car wheel along the road. You wouldn't even notice it!
Last edited by Colibri49; 16th Nov 2012 at 22:38.