Hirobo HI2521136 Collar 12 x 18 x 1 - RC Helicopter Shaft Collar  [HI2521136]

Helicopter shaft collar overview

This HIROBO collar (model HI2521136) is a small-scale RC accessory intended for use within Hirobo helicopter general parts. The product name indicates its working dimension of 12 x 18 x 1, making it suitable where a low-profile shaft retaining collar is required on rotating elements of model helicopters.

In practice this collar functions 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 an RC-scale part, intended for model helicopter assemblies rather than full-size equipment.

Installation notes: position the collar at the intended axial location on the shaft and secure according to your helicopter's existing retention method. Inspect mating surfaces for burrs or wear before fitting to avoid misalignment. During setup, check rotor or rotorhead runout after installation to confirm the collar does not introduce tilt or binding.

Tuning role: use this collar to fine-tune axial position of gears, bearings, or other rotating components when small positional adjustments are needed to reduce endplay or to align gear meshes. Small changes in collar placement can affect drivetrain smoothness, so apply incremental adjustments and verify performance on low-speed bench tests before flight.