Hirobo HI2521136 Low-Profile Shaft Collar 12 x 18 x 1 for RC  [HI2521136]

Purpose and tuning impact

This Hirobo collar (model HI2521136) is a compact accessory for Hirobo helicopter general parts. With dimensions of 12 x 18 x 1 it is chosen where a thin retaining collar is required on rotating components of model helicopters.

Functionally the collar acts as a mechanical stop and helps maintain alignment, reducing axial play and keeping shafts concentric with mating parts. It is specified for model helicopter assemblies and not intended for full-size machinery.

Installation notes: slide the collar into position on the shaft and secure using your model's chosen retention method. Inspect contact surfaces for wear or burrs before fitting to avoid misalignment. After installation, run a slow-speed check of the rotor assembly to ensure no binding or tilt has been introduced.

Tuning advice: use this collar to dial in axial position of gears or bearings when adjusting endplay or gear mesh. Small shifts in collar placement can change drivetrain smoothness, so make incremental moves and retest on the bench before flying.