Troubleshooting

Getting a multicopter to fly can be tricky, especially for those who are new to the world of RC and micro controllers. There are hundreds of variables that could stop your machine from flying. Successful troubleshooting depends on a systematic approach, eliminating each potential source of trouble until the problem is resolved.

The information here has been compiled from over two hundred different "my multicopter won't fly" situations, and is presented with the most common causes at the top.

General Troubleshooting - Applies to all multicopters

Motors

Are your motors spinning in the correct direction? If a motor is spinning in the wrong direction, all you need to do is reverse any two of the 3 ESC > Motor wires. This will reverse its direction.

Props

Do you have a clockwise prop on each clockwise motor, and a counter clockwise prop on each counter clockwise motor? Multicopters use two different types of props, clockwise (also known as Right hand, or Right, or R), and counter clockwise (also known as Left hand, or Left, or L).

A motor rotating clockwise needs a clockwise prop, and one rotating counter clockwise needs a counter clockwise prop.

Additionally, the props must be installed the correct way up. That means the printed/embossed numbers need to be facing up, not down.

ESCs

There are a number of common ESC related problems. ESC calibration is the most common. In order for a multicopter to achieve stable flight, the ESC throttle ranges need to be calibrated so that they are all the same. The procedure for calibrating ESCs is usually included in the ESC manual, but it is essentially the same for all common ESCs, and can be found here: ESC Calibration.

Some ESCs are programmable. For those ESCs, it is important to set the timing to Medium. The default setting (often Low) does not achieve good results with most motors.

It is important to remember that each ESC must be connected to the correct output pin on the multiwii, otherwise the machine won't fly.

Vibration

Vibration is a very common source of problems for beginners. If there is too much vibration being transmitted to the gyro, the signal to noise ratio on the gyro signal is too great for the multiwii to be able to make use of the signal.

The key to reducing vibration is to have a very stiff frame, and to couple the multiwii controller to it just the right amount. Frames made of aluminium, fibreglass and carbon fibre are generally much less prone to vibration than those made of injection moulded plastic or Lexan.

Coupling the multiwii to the frame is very important. The coupling needs to be sufficient for the gyro to be able to sense small movements of the frame, but not so strong that all of the vibrations created by the motors are transmitted to the gyro. Double sided foam tape is a very good way of achieving this, as are soft silicone grommets.

Too little coupling, such as when using rubber bands or springs, can result in the controller oscillating too much, and does not generally work well.