Hirobo HI2521122 Shaft Collar - 5 x 6.5 x 12.5mm for Helicopter Builds  [HI2521122]

Shaft spacer for radio-controlled helicopters

The Hirobo collar (HI2521122) is produced as a scale shaft collar for helicopter assemblies. Verify the stamped 5 x 6.5 x 12.5 dimensions against your model's shaft and stacked components before use.

Functionally it provides axial location and spacing within rotor linkages, swashplate stacks and similar shafted subassemblies where controlling end-play is important. Its plain design is meant to integrate with the airframe's existing hardware rather than supplant model-specific retainers.

Fitment notes: confirm the collar fits your shaft, align with neighbouring parts, slide into position and secure using the model's existing retention method (set screw, retaining clip or installed collar). After fitting, inspect for free rotation and acceptable axial play before powering up.

During setup, the collar can be used to adjust servo-to-rotor geometry and to lock axial positions once linkages and rotorheads are trimmed. Perform bench checks at low throttle to ensure no contact with blades, swashplate or control linkages.

This item is an RC model accessory and is not suitable for full-size machinery or non-hobby use.