Propeller balancing is a vital skill when learning about quadcopters. Quadcopter propeller balancing is important in achieving a stable flight, and it can significantly increase the life of your motors and batteries as well as your flight time.
The balancing of the rotor is imperative in quadcopters, since they use more than one propeller. If one propeller is operating more efficiently than the others are, it can develop an irregular pattern in flight and this could result into a crash. However, learning to balance these propellers is not difficult.
For starters, you need two objects that have flat horizontal surfaces, on the same height. Here, two coffee cups (of the same size) can work great. Make sure that they are tall enough to allow the propeller to sit vertically along the edges of the cups in such a way that the tip of the blade does not touch the tabletop or the counter. You will also need a blade balancer, some cyanoacrylate glue, and some fine sandpaper. Super glue is also ideal in this.
1. Balance the Blades
You can do this by sliding the balancer shaft through the center of the hub. Secure it into place with locking nut balancer. The coffee cups should be close enough so that the ends of the balancer shaft rests on the edges of the cups, to suspend the rotor between them. Position the blades horizontally, with the rotor balanced between the cups. If one of the blades is heavier, it will drop until both blades are aligned vertically.
Sand the underside of the heavier blade lightly along its length, and ensure that you avoid the leading and trailing edges. Do not overdo it, as you will have to work on the other blade as well. It is better to check the balance often, up until the rotors sit horizontally between the two cups, meaning the blades are balanced.
2. Balancing the Hub
In this step, you will have to place the rotor between the two cups with the blades vertically aligned. The rotor should spin to either side to show the hub needs some balancing. The direction of the spin is the guide to which side of the hub is lighter. A spin in the clockwise direction means the left side is lighter, and vice versa.
Apply some super glue on the lighter side of the hub and then check the balancing. If the glue is still wet, you can just wipe off excess glue or continue applying it until the rotor doesnt spin on its own. A balanced propeller can be placed between the cups and the blades positioned anywhere without the propeller spinning on its own. Dont forget that it can be difficult to achieve perfect balance, and the goal here is good balance.
You can get propeller-balancing kits to help you with this. They come with a stand that can be used instead of cups. They work well with blade balancing, but hub balancing can be difficult since their stands can be quite small.