In order for a helicopter to hover (stay in one place), the net sum of the forces and moments about its center of mass must be zero. (It is in static equilibrium.) Assuming small angles (sin and cos 1), the six equations that must be satis ed are: Fx =0= TMa1 W Fz =0=W TM My =0=`MTM hMTMa1 QT QMb1 Fy =0=TT TMb1 W Mx =0=hMTMb1 hTTT QMa1 Mz =0=QM `TTT `MTMb1 The following are known: W weight of the helicopter `M horizontal distance between the center of gravity and the main rotor varies hM vertical distance between the center of gravity and the main rotor `T horizontal distance between the center of gravity and the tail rotor hT vertical distance between the center of gravity and the tail rotor (1) (2) (3) (4) (5) (6) = 32,000 N = 0.96 m = 6.5 m = 0.72 m The following are unknown: TM thrust of the main rotor (N) TT thrust of the tail rotor (N) QM torque of the main rotor (N-m) QT torque of the tail rotor (N-m) pitch angle of the helicopter fuselage, positive nose up (radians) bank angle of the helicopter fuselage, positive tilted right (radians)