Lets have a look at Newton's Third Law of Motion
III. For every action there is an equal and opposite
reaction.
In
accordance with Newton's law of action and reaction, the
helicopter fuselage tends to rotate in the direction
opposite to the rotor blades. This effect is called
torque. Torque must be counteracted and or
controlled before flight is possible. In coaxial
helicopter designs, the rotors turn in opposite
directions to neutralize or eliminate torque effects.
However, the torque problem is especially important in
single main rotor helicopters with a fuselage mounted
power source. The torque effect on the fuselage is a
direct result of the work/resistance of the main rotor.
Therefore torque is at the geometric center of the main
rotor. Torque results from the rotor being driven by the
engine power output. Any change in engine power output
brings about a corresponding change in torque effect.
The greater the power from the engine, the greater the
torque effect.
To
overcome this torque effect, a secondary and opposite
force need to be applied to cancel out the torque
effect. Compensation for torque in the single main rotor
helicopter is accomplished by means of a variable pitch
tail rotor, or electrical driven tail rotor located on
the end of the tail boom. |
