How NSK’s new bearing can extend eVTOL flight range 

NSK, a Japan-based bearings and precision components manufacturer, earlier this year introduced an innovative gas turbine generator bearing specifically designed for electric vertical take-off and landing (eVTOL) aircraft and large drones.

According to the company, the new bearing delivers superior speed performance while significantly reducing lubricant supply requirements—enhancements that contribute to extended eVTOL flight range.

The key advancements of the bearing include enhanced high-speed revolution capabilities and a novel lubrication mechanism that cuts the necessary lubricant supply by approximately 80%.

Historically, eVTOL propulsion systems have relied heavily on complete motorisation. 

However, as demand grows for longer flight ranges and improved transport capabilities, the market is shifting towards high-output, compact, and lightweight hybrid motors. 

Gas turbine generators, in particular, have emerged as a leading option for these hybrid systems due to their ability to use biofuels and hydrogen, making them attractive for carbon-neutral aviation.

One major challenge in extending the eVTOL flight range lies in optimising the high-speed revolution performance of gas turbine generator bearings. 

To address this, NSK developed a bearing capable of operating at over 2.5 million dmn (a measure of the bearing’s pitch diameter multiplied by its rotational speed). This performance is achieved with minimal lubrication needs, further enhancing efficiency.

Boosting flight range

Traditional jet lubrication systems, commonly used for high-speed bearings, require large volumes of oil and result in high power loss. 

Although under-race lubrication offers reduced oil usage, it is less versatile and more costly. 

NSK’s new solution overcomes these limitations by introducing an improved spacer design that temporarily stores lubricating oil and uses centrifugal force to supply the optimal amount to the bearing.

According to the company, this mechanism reduces oil consumption to just 25% of the amount required by conventional jet lubrication, while also cutting power loss by 33%. 

Additionally, the lower oil usage allows for lighter scavenge pumps and smaller lubricant tanks, further contributing to increased flight range.

By combining high-speed revolution performance with an efficient lubrication system, NSK’s new gas turbine generator bearing represents a major advancement for the eVTOL and drone markets. 

The solution offers manufacturers a way to improve performance and efficiency while supporting environmental sustainability.