Hirobo HI0304170 pinion gear for Embla EB 15T motor drive  [HI0304170]

Pinion gear for Embla EB

This is an RC-scale replacement pinion gear intended for use with Embla EB-series helicopters. The item is identified by Hirobo model HI0304170 and carries a 15T tooth count as part of its designation, making it a direct swap where a 15-tooth motor pinion is required.

Functionally, the gear serves as the motor pinion in the drivetrain, transmitting torque from the motor to the main gear train and influencing overall gear ratio and rotor response. Choosing the correct tooth count is a common tuning step to adjust head speed and tail sensitivity on electric RC helicopters.

Installation is straightforward on compatible setups: align the pinion on the motor shaft, ensure proper mesh with the spur gear, and secure the pinion using its set screw or retaining method. After installation, check mesh and bearing alignment, then perform a bench test at low throttle to confirm smooth engagement before flight.

Notes for maintenance and tuning: inspect teeth for wear after heavy use, keep the mesh neither too tight nor too loose to avoid premature wear, and consider swapping tooth counts only within the limits recommended by your helicopter's drivetrain layout.