3x7x4S Collar for Hirobo Helicopter Rotor Links - Hirobo HI2521071  [HI2521071]

Compact collar for tight clearances

This component is an RC-scale replacement intended for Hirobo helicopter assemblies where precise axial spacing is required. The 3 x 7 x 4S marking highlights its compact form, making it suitable as a small spacer or locating collar in rotor head linkages and similar parts.

To install, slide the collar onto the designated shaft or pin and secure it using the existing fastening arrangement of the model. After fitting, verify axial alignment and minimal play, then re-tighten the host fastener to the manufacturer's recommended torque to prevent loosening.

For tuning work this collar provides repeatable positioning so that blade pitch and grip alignment remain consistent. Use it when adjusting pitch geometry or replacing worn locating components during routine servicing.