Using the natural characteristics of helicopter aerodynamics, The NOTAR® anti-torque system provides safe, quiet, responsive, FOD-resistant directional control.
The enclosed variable-pitch composite blade fan produces a low pressure, high volume of ambient air to pressurize the composite tailboom.
The air is expelled through two slots which run the length of the tailboom on the starboard (right) side, causing a boundary-layer control called the "Coanda Effect". The result is that the tailboom becomes a "wing", flying in the downwash of the rotor system, producing up to 60 percent of the anti-torque required in a hover. The balance of the directional control is accomplished by a rotating direct jet thruster .
In forward flight, the vertical stabilizers provide the majority of the anti-torque, however directional control remains a function of the direct jet thruster.
The NOTAR® anti-torque system eliminates all of the mechanical disadvantages of a tail rotor, including long drive shafts, hanger bearings, intermediate gearboxes and ninety-degree gearboxes.