Hirobo HI2521136 12 x 18 x 1 Shaft Collar for RC Helicopters  [HI2521136]

RC helicopter shaft collar overview

This Hirobo collar (model HI2521136) is a compact RC accessory intended for use within Hirobo helicopter general parts. The 12 x 18 x 1 dimension provides a low-profile shaft retaining collar suitable for rotating elements on model helicopters.

In operation this collar serves as a mechanical stop and alignment aid, limiting axial play and helping maintain concentric assembly of shafts and mating components. It is described here strictly as a model helicopter part rather than equipment for full-size machines.

Installation notes: slide the collar to the intended axial position on the shaft and secure it using your helicopter's existing retention method. Inspect mating surfaces for burrs or wear before fitting to avoid misalignment. After installation, check rotorhead runout to confirm the collar does not introduce tilt or binding.

Tuning role: use this collar to set the axial position of gears, bearings, or other rotating parts when small positional adjustments are needed to reduce endplay or align gear meshes. Apply incremental adjustments and verify performance with low-speed bench tests before flight.