Hatroi HA215 flange for #643 #644 YS4C-63~70 OS4C-70~81, RC engine shaft flange spare  [HA215]

RC-scale engine shaft flange

This Hatroi HA215 flange is an RC-scale accessory designed as a direct replacement flange for the listed part codes and engine models. It is intended for use with #643, #644 and engines identified as YS4C-63~70 and OS4C-70~81, preserving the original fitment references exactly as specified by the product name.

Use this flange where a worn or damaged flange requires replacement to restore proper shaft engagement. The component helps maintain concentric mounting of the engine shaft to prop or coupling systems, and its role in an RC model is limited to correct mechanical connection and alignment for glow engines at model scale.

Installation notes: verify the flange seating surface and fastener holes match the original part, clean mating surfaces before reassembly, and torque fasteners to the values recommended by your engine or model manual. Check axial alignment after installation to confirm the shaft runs true before full operation.

Tuning role: replacing a degraded flange can reduce shaft runout and vibration at the model scale, making throttle response and idle stability easier to evaluate during engine setup and on-track adjustments.