Korea's KIMM achieves first domestic development of key rotorcraft powertrain parts

South Korean researchers have succeeded in domestically developing key components for next-generation rotorcraft that the country had previously relied entirely on imports to obtain.

A research team led by Lee Han-min, head of the Industrial Machinery DX Research Laboratory at the Korea Institute of Machinery and Materials' Virtual Engineering Platform Research Division, announced Monday it had developed, for the first time in South Korea, core technologies for four key components of a next-generation rotorcraft power transmission system: the clutch, gear, housing and bearing.

Unlike fixed-wing aircraft, rotorcraft generate lift through rotating blades, or rotors, enabling vertical takeoff and landing as well as short-distance and low-speed flight. Helicopters and tiltrotors are the most representative examples.

The power transmission system transfers engine power to the rotor and must meet demanding technical requirements for high speed and light weight. The research team developed independent design and analysis technologies for each of the four key components and completed verification through prototype fabrication and performance testing.

In the clutch area, the team developed component and system design and analysis technologies, and secured core technologies to improve the heat resistance, low-loss performance and wear resistance of both dry and wet friction materials.

For gears, the team developed body shape design and analysis technologies as well as hybrid dynamic analysis technologies to achieve high-speed, lightweight performance. Using an independent design process, the team produced a lightweight gear comparable to the internationally advanced SAFRAN Arriel 2 standard and completed technical verification through quasi-static testing.

In the housing area, the team developed topology optimization and integrated analysis technologies, and secured process analysis and optimization technologies for 3D printing fabrication.

For bearings, the team developed shape design and analysis technologies, along with reinforcement learning-based design optimization and computational fluid dynamics-based power loss analysis technologies.

The work established an independent design, analysis and optimization process that had previously been absent in South Korea, and built in-house design capabilities for each of the four key components. Prototypes of each component were produced and validated through static, durability, lifespan and efficiency tests. The team also secured design and analysis processes along with verification data that can be immediately applied to future domestic development of the components.

"Establishing an independent technology base in the field of aviation power transmission systems, which had long been dependent on foreign technology, carries significant meaning for strengthening national defense technology security," Lee said. "We will continue research and development and pursue industry-academia-research cooperation so that this technology can be actively utilized when next-generation rotorcraft reach the commercialization stage."