5 x 6.5 x 12.5 Shaft Collar for RC Helicopters Hirobo HI2521122  [HI2521122]

Technical notes on shaft collar use

The Hirobo collar (HI2521122) is an RC-scale shaft collar intended for use within helicopter parts and assemblies. Confirm the stamped dimensions 5 x 6.5 x 12.5 match your shaft and stacked components prior to installation.

As a component, the collar provides axial location and spacing in rotor linkages, swashplate stacks and other shafted subassemblies where limiting end-play is necessary. Its neutral profile is designed to integrate with the model's existing mounting hardware rather than replace specific retainers.

Installation advice: ensure the collar fits the shaft, align with neighbouring parts, slide into position and fasten using the retention method supplied on your model (for example set screws, retaining clips or an installed collar). After securing, check for smooth rotation and controlled axial play before flight.

When tuning, use the collar to adjust servo-to-rotor geometry and to lock axial positions after trimming linkages and rotorheads. Perform bench testing at low throttle to ensure no interference with blades, swashplate or control linkages.

This product is intended for RC model use only and is not suitable for full-size or non-hobby applications.