HP and RPM (engine(s) intake and main rotor shaft)or main rotor RPM and de-multiplying factor.
a medium tonnage ussualy has a 4000 HP with main around 300 rpm and two engine couplings rated between 20,000 to 50,000 rpm (just for example)
kis1 gave the answer I think. I haven't heard though of a puller tail rotor. so considering that all are thrusters, left or right depends on the rotation of the main if its clockwise or anticlockwise.
hi dspDAD,
I wouldn't worry too much about precession as the rotor rpm is relatively low around 300 for most helicopters.
the angle mentioned here(I think it was 15 degreees) is a natural angle of the cone due to the aerodynamic forces in forward flight. the angle varies(increases) with speed...