Would a flywheel work

[Vfrpilotpb]

If a counter-rotating flywheel which developed an equal centrifugal force of that of the main rotor, was fitted to the main gearbox of any helicopter, could this be used as an anti-torque mechanism, and ultimately do away with the tail rotor?:confused:

[Nick Lappos]

No, because the flywheel does not develop a continuous torque to counter the main rotor torque. The torque balance relationship of the tail rotor does not have anything to do with Centrifugal effect.

Remember that the torque developed by the engines and transmission is the equivilent of you standing on the top of the helicopter pushing on the rotor blades to make them spin. Your feet are on the deck of the helicopter, pushing on that deck as you lean into the push on the blades. The blades turn one way because you pushed them with your hands, and the fuselage will turn in the opposite direction because you pushed it with your feet (if there were not all that friction with the aircraft on the ground).

[Vfrpilotpb]

Thank you Nick, that question has been banging around my head for quite some time now, I have been slightly confused by this energy possibility after reading about the DH Mosquito which had Merlins that turned the propellers in opposite directions so as to allow the A/c to take of in a straight line, unlike the Bristol Beaufighter whose Hercules engines turned the props in the same direction and caused the pilots allsorts of problems especially when landing .

[Nick Lappos]

VFRPilotPB,
The counter rotating engines help square away the handling at high angles of attack, mostly to cure the P factor, which is really not torque (although it is called that by many people). The prop is really a rotor with no flapping relief. When it operates it is exposed to a wind velocity that is not purely axial (as for example when in a sideslip or in an angle of attack) so the thrust center is not at the prop spinner. The prop develops a strong turning moment as well as its normal thrust. Conventional props (top blade spins to the left when viewed from the cockpit) will pull the aircraft to the right (and need left rudder) during high angle of attack climbouts. That's because the down sweeping prop blade has an increased angle of attack, and vice versa.

The engine torque also rolls the aircraft right, and forces left aileron, which calls for left rudder (that part is due to true torque).