Hi Rob, there are not that many folks on these forums that I have faith in, but you are one of the few that I do.
The old X8 prop efficiency nugget .....
There are as many opinions as there are you-know-whats on this subject but the general consensus seems to be to either lower the gains of the upper motors - thereby voluntarily relinquishing a percentage of available lifting power - or to increase the pitch of the lower props to establish some sort of balance of efficiency and to help prevent the lower props freewheeling.
The trouble is, carbon props are not generally supplied with different pitches for each length. So it is not possible, for example, to install a smaller prop with a one inch higher pitch. One can only install a longer prop with a slightly higher pitch.
In your opinion, is this latter option workable or does a longer prop on the lower motors introduce other undesirable elements?
Regards, Graham Hay