Replacement Hatroi HA215 Flange for #643 #644 and YS4C-63~70 OS4C-70~81 Shaft Mount  [HA215]

Flange for RC glow engine shafts

The Hatroi HA215 flange is produced as a direct-fit RC-scale replacement for the part numbers and engine models cited. It is intended for use with #643, #644 and engines designated YS4C-63~70 and OS4C-70~81, keeping the same fit references presented in the product name.

Use this flange when a worn flange needs replacement to restore correct shaft engagement. The component maintains concentric mounting between the engine shaft and prop or coupler, and its function is limited to mechanical connection and alignment on model glow engines.

Installation notes: confirm the seating surface and bolt hole alignment match the original part, clean both mating surfaces before assembly, and tighten fasteners to the torques recommended in your engine or model documentation. Verify axial alignment after fitting to ensure the shaft runs true prior to regular operation.

Tuning role: replacing a compromised flange reduces runout and vibration at model scale, which aids in evaluating throttle response and idle during engine setup and track testing.