NOTAR is an acronym that stands for "No Tail Rotor." It refers to a type of propulsion system used in helicopters. Unlike traditional helicopters that possess both a main rotor and a tail rotor, a NOTAR-equipped helicopter does not require a tail rotor to counteract the torque produced by the main rotor. Instead, it utilizes an innovative system to control and counteract the torque.
The NOTAR system is based on the principle of using a fan located inside the helicopter's fuselage to draw in air from above the rotor and expel it through slots in the tail boom. This expelled air creates a Coandă effect, which causes the airflow to adhere to the tail boom surface and create a low-pressure area on one side. This low-pressure area generates a sideways force, known as lateral thrust, which serves as the counteracting mechanism for torque produced by the main rotor.
The benefits of the NOTAR system include increased safety, reduced noise, and improved performance compared to traditional helicopters with tail rotors. The absence of a tail rotor eliminates the risk of accidents, such as tail rotor strikes, experienced in conventional helicopters. Additionally, the NOTAR system reduces noise levels, making it an excellent choice for operations in noise-sensitive areas. It also provides increased maneuverability, as the lateral thrust can be controlled and directed to provide stability during flight.
In conclusion, NOTAR is a propulsion system used in helicopters that eliminates the need for a tail rotor to counteract the torque produced by the main rotor. It achieves this by utilizing a fan and Coandă effect to create lateral thrust, providing improved safety, reduced noise, and enhanced maneuverability.
