Balanced propellers will reduce the vibrations that transfer to your flying camera as these small movements can result in blurred stills and shaky video.
How Can I Improve the Quality of My Drone’s Photography?
Drone manufacturers have fairly good quality control for their airframes but like any airborne device their smoothness depends on proper balancing of the rotating components. In our case, that would be the propellers. We’ll assume for the moment that the motors and propellers are running true and aerodynamically balanced. More on that below.
First, Why Should the Propellers be Balanced?
Well, why do drivers balance the tires on their cars? Experienced drivers know that unbalanced tires lead to vehicle vibrations when their speed picks up. The same holds true for drone propellers. When one part of the propeller is heavier, the spinning mass delta will cause vibration that increases with speed.
The Solution is Propeller Balancing
To balance the propellers, you’ll need to purchase a balancing kit; example in the picture above. It works by attaching a rod to the propeller and the pair is then balanced on a very low friction support. Any propeller imbalance will cause the propeller to roll until the heaviest part of it hangs below. Balance is achieved by adding or removing material until the propeller is stable.
Here’s the How To:
Place the propeller so it’s horizontal and watch for one side or the other to dip. Then sand/scrape off a small amount of material from the heavier blade such as on the bottom side near the tip. (Or add a little scotch tape to the lighter blade.) Horizontal balancing will take out most of the vibration.
Vertical balancing is next. The concept here is that whatever imbalance that remains is in the hub. Place the propeller so it’s vertical and look for motion. Balance is again achieved by adding or removing material until the propeller is stable, but this time it’s at the hub. If needed, sand/scrape material from the heavy side of the hub, between the propeller blades. This step may take longer because more material typically needs to be removed.
Your propeller is properly balanced when it remains stationary on the support no matter which position the blades are placed.
How Do I Ensure the Propellers are Running True?
Great question and easily answered! Start your drone on an elevated surface, such as a table, but don’t take off. Then observe the blade tips, looking for spread. There will be little to no spread if the blades are running true, which means they’re aerodynamically balanced.
If there’s spread between the tips, then the blades have different amounts of lift or the motor/shaft are bent. This means that your propeller is aerodynamically unbalanced, causing vibration. Typically, the culprit will be just one of the propellers so you can rule out a bent motor by swapping the propellers (e.g. exchanging one black hub propeller with the other). If whatever spread you saw on the one side does the same thing on the other, then the propeller is bad.
Balanced propellers will lead to the smoothest possible photography with your drone. Whatever residual vibration that appears in your video can be taken out with post-processing software.