Replacement Tail Gear Box for GPH 346, Model HI0403251 by Hirobo  [HI0403251]

Tail gearbox function and fit for GPH 346

The component marked Hirobo HI0403251 is supplied as a replacement tail gear box for the GPH 346 helicopter series. Below is a practical summary of how the part sits in the tail drive and notes for fitting and setup on model helicopters.

Its role is to locate and support the tail gears inside the tail boom and to transfer rotational motion to the tail rotor assembly. As an aftermarket replacement, it is intended to restore correct gear engagement and reduce slop when the original gearbox is compromised.

Fitting checklist: confirm the HI0403251 part reference against the airframe documentation prior to installation, inspect mating gear faces and bearings for wear during the changeover, and fine-tune gear mesh and alignment after assembly. Do not assume cross-model interchange unless explicitly specified by Hirobo.

Tuning benefits: a properly installed tail gear box helps reduce drive play and improves tail authority, which contributes to steadier yaw control and smoother flight handling for GPH 346 models.