Hirobo HI2521105 3 x 4-6 x 17 Replacement Collar for RC Helicopter Shafts  [HI2521105]

Precision collar for helicopter shafts

This Hirobo HI2521105 collar, 3 x 4-6 x 17, is offered as a replacement part for hobby helicopter maintenance. It secures axial position on rotating shafts and helps maintain geometry during rebuilds or adjustments.

Intended to integrate with routine Hirobo maintenance, the collar reduces small axial movement and serves as a replaceable locating item for worn components. It is supplied as a service part rather than a full mechanical assembly.

Installation guidance: position the collar to the required shaft location and tighten without over-clamping to prevent shaft damage; verify running clearance after fitting and confirm rotor alignment at low speed prior to regular use. Use the collar to lock a preferred trim setting and perform repeat test flights to validate stability.