Hirobo HI2521105 Collar 3 x 4-6 x 17 RC helicopter collar part  [HI2521105]

Small collar for helicopter assemblies

This Hirobo HI2521105 collar is an RC-scale helicopter hardware item listed as a collar for general helicopter parts. It serves as a compact shaft collar used to secure axial position on rotating shafts and to maintain geometry during repairs or tuning.

Designed to integrate with Hirobo helicopter maintenance and rebuild tasks, the collar helps stabilize small axial movement and offers a replaceable option for worn locating components. The product is presented as a service part for hobby-grade rotorcraft assemblies rather than a standalone mechanical assembly.

Installation notes: slide the collar to the required shaft position and secure without over-tightening to avoid shaft damage; check running clearance after fitting and verify rotor alignment under low-speed checks before regular operation. For tuning, use the collar to lock a preferred trim position and repeat test flights to confirm stability.