Hirobo HI2521061 Collar 5 x 8 x 2.5 RC helicopter linkage part  [HI2521061]

Small collar for helicopter linkages

This Hirobo collar is a compact RC retention part sized 5 x 8 x 2.5 designed to locate and secure linkage pins and shaft interfaces in helicopter assemblies. It performs a mechanical spacing and retaining function where tight, repeatable positioning is needed during assembly or repair.

Installation notes: make sure the collar inner and outer diameters match the shaft and mating hole, slide the collar onto the shaft or pin until it seats evenly, then confirm adjacent linkages move freely before tightening any retaining screws. Verify axial alignment after fitting to prevent binding in cyclic or pitch linkages.

Tuning role: collars of this dimension are useful for trimming endplay and refining control geometry; small shifts in collar placement change lever lengths by fractions of a millimetre, which can be critical for precise neutral and trim settings.