7 x 8 x 4 Retention Collar HI2521146 for RC Helicopter Tuning by Hirobo  [HI2521146]

Compact 7x8x4 retention collar for RC heli

The Hirobo HI2521146 collar, specified at 7 x 8 x 4, is a compact clamp-style retention part designed to locate shafts, linkages, and sliding assemblies within RC helicopters and comparable models.

As a replacement accessory it prioritises axial positioning rather than heavy load support. In tuning and setup it helps stop cyclic linkages, tail shafts, and intermediate studs from shifting under vibration. Verify the collar's 7 x 8 x 4 dimensions against your shaft and bore before fitting to ensure correct seating.

Fitting tips: remove burrs and debris from mating surfaces, slide the collar into place and ensure it seats without impeding rotation, and check the assembly after a short run. Replace the collar if the fit loosens or wear appears; it is supplied as a swap-in maintenance aid for RC helicopters.