Hirobo HI2521091 Collar 5 x 7 x 18.3  [HI2521091]

Helicopter Collar Part

This is an RC-scale collar designed for helicopter general parts, identified by Hirobo model HI2521091. The part’s title includes the dimensional reference 5 x 7 x 18.3 which is the key technical attribute used to match shaft fit and axial spacing in small-scale helicopter assemblies.

The collar functions as a mechanical spacer and locating feature within rotorlinkage or general transmission stacks on model helicopters. It is intended to provide predictable spacing that helps maintain alignment between mating components and to support incremental tuning where precise axial position matters.

Installation guidance is intentionally general: confirm the dimensions listed in the product name against the target shaft or bore on your model, slide the collar into position where required by the assembly, and secure according to your helicopter’s existing hardware and manual. This description treats the item strictly as an RC accessory and does not imply any full-scale application.