Hirobo HI0301041 XRB SR Lower Rotor Head Assembly L=125  [HI0301041]

Precision lower rotor head for XRB SR

This lower rotor head assembly is an RC-scale replacement part designated by Hirobo as HI0301041 and identified for use with XRB SR series helicopters at length L=125. The part serves as the lower hub linking blade grips and the lower swash linkage, so its condition has a direct effect on rotor tracking and cyclic response.

Installation guidance: confirm compatibility with your current upper and lower linkages before completing assembly, make sure blade grips are oriented to match the original geometry, and inspect nearby ball bearings and link pins for any wear. Observe the helicopter manufacturer’s recommended fastener torque and, where appropriate, secure fasteners with a medium-strength threadlocker.

Tuning role: fitting a new lower rotor head can reduce slop in the rotor system and make pitch inputs more immediate, which helps during trimming and cyclic setup in flight testing. After installation, perform static blade tracking and a low-power hover check to verify correct assembly and rotor balance.