Hirobo HI2521102 Collar 5 x 8 x 3.5 mm for RC Helicopter General Parts  [HI2521102]

Shaft collar for model helicopter assemblies

The HI2521102 collar by Hirobo is provided as a replacement component within the helicopter general-parts category and carries the 5 x 8 x 3.5 identification. It functions as a minimal mechanical collar to locate rotating shafts and hold spacers in place without suggesting compatibility beyond the manufacturer's general parts classification.

When fitting the collar on the bench, slide it into the required axial position and secure the surrounding hardware to manage endplay. As a component-level accessory, installers should confirm the collar's fit against the intended shaft and use the fastening approach outlined by the helicopter's service guide.

For setup and periodic checks the collar is a practical tool for adjusting spacing between bearings or gears and for restoring shaft alignment after maintenance. Remove debris before fitting and run a clearance check to ensure no rubbing occurs in the rotor drive or gear train.