Understanding Autorotation in Rotorcraft

Autorotation is a type of autorotational rotation that occurs in a rotor when it is not subject to any external torque. It is a self-sustaining rotation that is maintained by the internal dynamics of the rotor itself, without any external input.

In autorotation, the rotor blades are angled so that they produce lift, even though the rotor is not spinning. This lift creates a torque that causes the rotor to continue rotating, even after the initial impulse has been applied. The rotation rate of the rotor increases as the lift force increases, and the rotor will continue to rotate at an increasingly faster rate until it reaches a stable equilibrium.

Autorotation is commonly used in helicopters and other rotorcraft to slow down or land the aircraft when the engine is not running. By entering autorotation, the pilot can control the descent rate of the aircraft and make a safe landing without the need for power from the engine. Autorotation is also used in some situations where the engine needs to be shut down, such as during maintenance or in an emergency.

Autorotation is a critical skill for helicopter pilots to master, as it is essential for safe landings and emergency procedures. The ability to enter and maintain autorotation is a key aspect of helicopter flight training, and pilots must practice this skill regularly to ensure proficiency.