SX Series Autorotation Torque Limiter Upgrade HI0404543 by Hirobo  [HI0404543]

Limiter function and purpose

The Hirobo HI0404543 torque limiter is an RC rotor-head component that controls autorotation torque transfer to the drivetrain. It appears as a common spare across Eagle, Freya, EX and SX series helicopters and is used both to restore original behaviour and to fine-tune autorotation response.

By moderating torque during free-spinning conditions, the limiter helps produce a more controlled rotor deceleration during autorotation. The item is designed for direct replacement, using the original mounting points to keep rotor tracking intact.

During fitment ensure the part aligns correctly with the head interface and that no machining is necessary. After assembly run static checks and a cautious hover test to validate autorotation performance before progressive tuning.

A practical choice for pilots seeking consistent rotor slowdown and predictable autorotation response while maintaining factory alignment.