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.
|
