A   = Axis of rotor rotation
Vr  = Velocity of air due to blade rotation
Vi  = Velocity of air inflow into the rotor
Vt  = Total airflow velocity
L   = Lift of the airfoil
D   = Drag of the airfoil
R   = Resultant force on airfoil
F    = Force that drives the airfoil around the axis
L1  = Lift force transmitted to the mast
Lt   = Total lift of the rotor
T    = Thrust of the propellor
W  = Gross weight of the gyro
CG = Centre of gravity of the aircraft