HIROBO HI2521101 3 x 4 x 3.5mm Nylon Collar for Helicopter Link Assemblies  [HI2521101]

Link-spacing collar for RC use

This RC-scale collar is a small spacer designed for use in helicopter linkages and other miniature assemblies where controlled gap and alignment matter. The part is intended as a neutral replacement accessory for model maintenance, not for full-size machines. It serves to set consistent clearance between shaft and link components and to keep small pins centred during boost or cyclical adjustments.

Material and fit: the collar’s nylon construction provides low friction and basic wear resistance suitable for light mechanical interfaces found in rotor heads, swash linkages, and feeder links. Nylon reduces binding against metal pins and supports smoother motion where tight tolerances are required.

Installation notes: clean mating shafts and pins before fitting, slide the collar onto the pin until it seats against the shoulder, and check free movement of the linked parts. If play persists, verify pin diameter and seating surfaces rather than forcing a smaller or larger collar. The component works as a passive spacer; secure nearby fasteners to manufacturer torque values for the assembly.

Tuning role: use the collar to fine-tune control geometry by changing spacing in small increments, helping to reduce slop and maintain consistent lever lengths across link sets. Because it is a simple mechanical spacer, it is most effective when used alongside careful setup of link angles and control throws.