The auto rotation is one of the most interesting, and challenging maneuvers that an RC helicopter can perform. Autorotation is the state of flight where the RC helicopters rotors spin freely, without input from the engine. This means that the rotors only have 2 energy sources: their own momentum and the upward motion of air over the blades, caused by the helicopters descent. In an autorotation landing, the pilot needs to manage the descent speed of the rc helicopter, so that enough energy is left in the blades to reduce the landing speed to a safe amount. This picture shows the difference between powered and autorotation RC helicopter flight.

Not only are autorotations a crowd pleasing maneuver, they are of vital importance during an equipment failure. If the engine of the RC helicopter stops for any reason, then auto rotation flight begins immediately. It will be up to the pilot to handle the situation accordingly an land the RC helicopter safely.

Fortunately, there is a way to practice autorotations safely, without excessive risk to the RC helicopter. Begin by setting the throttle hold position to about 30 percent, or just enough such that the RC helicopter will barely hover. Mark the throttle hold switch by placing a piece of fuel tubing over it. This will let you find it quickly, by giving it a different feel than the other switches.

You can master the autorotation by following this procedure:

1. Learn to control the descent – The first step is to learn how to fly a controlled descent under low power. Take off, and then start by turning the RC helicopter so that it faces into the wind. Then reduce your throttle and collective pitch so that the RC helicopter descends gradually. Keep the nose pointed straight ahead, and keep the RC helicopter level. After you have descended to about 20 feet, increase power and level off. Continue these practice runs until you become very confident.
2. Now try it with low power – After you become comfortable with descents at normal throttle settings, you are ready to try them with the throttle reduced. This will allow you learn to autorotate, while allowing you to bail out if the situation becomes dangerous. Practice step one again, but this time do it with the throttle hold engaged. You will want the RC helicopter to be very high when trying this for the first time. Like before, have the RC helicopters nose pointing into the wind. Engage the throttle hold, and use the collective to control the descent rate. Just like in step one, increase the throttle and level out at around 20 feet above the ground. Repeat this until you are comfortable with descents at low power, and then attempt a controlled landing. Landings at low power involve the following steps:
   1. Entry – This occurs when you reduce power, and start to descend.
   2. Descent – Descent should be relatively rapid, so that more energy is left in the rotor blades for landing.
   3. Flare – As you near the ground, pull the nose of the helicopter up and use the collective to reduce descent speed.
      
   4. Landing – Use the last of the rotors momentum to slow your final descent to a safe amount, and land the RC helicopter.

   It is very important that you let the RC helicopter descend relatively rapidly at first – you will need the extra rotor speed to land safely.

3. Reduce throttle power - After mastering a controlled descent and landing at 30 percent throttle, continue practicing at lower and lower throttle settings. Eventually, you should be able to execute a polished landing with the engine at idle.

Congratulations! You have just mastered autorotation landings.