Model maintenance

Bearings 13-08-2020

First-person view (FPV) drone racing is a competitive sport where participants pilot drones via a camera and a head-mounted live stream display. In such competitive races, winning can come down to the smallest of margins, so mechanical components must always perform optimally. Here, Chris Johnson, managing director of RC bearing specialist supplier SMB Bearings, advises on selecting and maintaining bearings for drones.

Competitive drone racing has gathered pace over the last five years and its popularity isn’t showing any signs of wavering. In January, Transparency Market Research released a projection report predicting the drone racing market will reach $237 million by the end of this year and will launch into three-fold growth by 2027.

Typically, drones are a high value piece of kit, however, it’s not just money that buys the best racing drones, it’s technical knowledge, expert design and attention to the smallest of mechanical components. If you take a close look at drone race results, you’ll find that most winning drones were custom-built by their owners. So, what can we learn from this?

While you may not be looking to compete in the Drone Racing League, if you’re less of a tinkerer and more serious about achieving the very best service life from your racing or camera drone, the quality of your bearings can significantly impact your performance.

Choosing your bearings

Precision EZO bearings are often specified for drone motors due to their inherent low noise and vibration characteristics. The quality of drone bearings is critical as the cost of sudden bearing failure can be very high. For this reason, it’s recommended that pilots only use reputable suppliers.

EZO shielded bearings are lubricated with a low noise, low torque grease. Additional lubrication with oil is not recommended for shielded bearings as this can lower the grease viscosity making it less effective. As the bearings are lubricated for life, this cuts down on the risk of under or over lubrication during maintenance, which is a leading cause of bearing failure.

Checking for wear

Drone maintenance extends beyond bearings and should be conducted regularly, with a quick visual inspection before and after every flight. As a general guide, you should conduct a thorough maintenance check every month, but this schedule depends on your usage. Here are a few checks that you can carry out:

Firstly, visually inspect your landing gear and chassis for cracks and signs of damage. Check for worn or frayed wiring, inspect your battery packs for deformities and check that your antenna is in good working condition.

Next, clean carefully around each motor and propeller then check for rotational friction. If a motor or propeller is not spinning freely, the motor bearings may be contaminated or worn in which case you will need to disassemble the motor. Also be sure to check your propellers for cracks.

If you remove the bearings from the motor, you can place them on the end of a pen or pencil and check the rotation. Try gripping the outer ring of the bearing between finger and thumb and pressing the bearing on to the pen/pencil tip while rotating it. This usually makes it easier to feel any roughness. If the bearings do not feel completely smooth, they should be replaced. Bearings should not need replacing very often, however a heavy impact, such as a hard landing, can affect bearing service life. If a bearing does need replacing, make sure you choose a quality replacement.

Finally, as with mechanical components, your drone control station software and firmware should also be given some TLC. Making sure that you’ve installed the latest updates will decrease the risk of security vulnerabilities, fix any reported issues and increase operational smoothness.

It’s important to check your components for pesky signs of wear as this will ensure that your valuable drone remains airworthy for longer. This will lower the chance of accidents and will ultimately provide cost savings in the future.

Our determination to remain specialised gives us a high level of product knowledge, providing bearing and lubrication solutions to existing or potential customers, whether individuals or large corporations. We don’t just sell bearings, we help to solve your problems. - Chris Johnson, managing director of SMB Bearings.