Hirobo HI2521061 Precision Collar 5 x 8 x 2.5 for RC linkages  [HI2521061]

Retention collar for RC shafts

This Hirobo collar is a small-scale RC retention part with dimensions 5 x 8 x 2.5, made to locate and retain linkage pins and shaft interfaces in helicopter assemblies. It serves purely mechanical functions as a spacer and retainer where compact and repeatable positioning is required for service or initial fitting.

Installation notes: ensure the collar inner diameter matches the shaft and the outer diameter fits any bore, slide the collar onto the pin or shaft until it seats uniformly, and confirm adjacent linkages rotate freely before securing any screws. Verify axial alignment to prevent binding in cyclic or pitch systems.

Tuning role: collars of this size are effective for adjusting endplay and refining control geometry; small shifts in collar location change lever lengths by small fractions of a millimetre, which can influence trim and neutral setting accuracy.