246-3914-000

Role in the anti-torque and yaw-control system

The tail rotor counters main rotor torque and provides directional control around the helicopter vertical axis. Within this system, the 246-3914-000 hub carries three blade attachment positions and transmits rotation from the tail gearbox output flange to the blade set. Its articulated structure also allows the blade pitch to change in response to the tail rotor control mechanism.

During operation, the hub is subjected to torque, centrifugal forces, aerodynamic loads and repeated pitch-control movement. Correct attachment geometry, bearing condition, hinge movement and documentation are therefore important to the operation of the complete tail rotor. The hub is a mechanical assembly rather than a complete rotor and is supplied without treating the blades as part of the hub designation.

Relationship to 246-3904-000 Series 01 and the blade set

The 246-3904-000 Series 01 tail rotor is the parent assembly documented with one 246-3914-000 hub and one matched set of three 246-3925-00 tail rotor blades. These are separate part numbers: 246-3914-000 identifies the hub, while 246-3925-00 identifies the blade set.

The hub and blades must be selected as an approved matched combination. Maintenance documentation warns against installing a hub and blades from different sets unless they were statically balanced together by the manufacturer or an approved repair organization. When ordering, identify whether the requirement is for the hub only or for the complete 246-3904-000 Series 01 tail rotor assembly.

Confirmed applications and installation interface

Technical documentation lists 246-3914-000 for Mi-8MTV, Mi-17 and Mi-171 helicopters. The associated rotor passport also covers configurations identified as products 240, 80MT, 171/AMT and 172/MTV, subject to the specified engine and tail rotor control arrangement, as well as the documented Mi-35MS installation. Applicability must be confirmed against the exact helicopter modification and installed rotor system.

The hub mounts on the tail gearbox driven-shaft flange. Pitch change is transmitted through the control rod inside the gearbox output shaft and the hub mechanism to the three blade positions. Installation, alignment, locking and balancing are maintenance operations that must follow the approved aircraft manual and component documentation.

Resource control, documentation and ordering

For configurations covered by the current documentation, the stated time to first overhaul and overhaul interval are 1,000 operating hours, while the assigned service life is 3,000 hours. The calendar limit may be seven or eight years depending on the helicopter configuration. Within the assigned life, the calendar service time and number of hub repairs are determined by technical condition and the applicable records.

For a quotation, provide the required quantity, aircraft type and modification, parent tail rotor designation, required condition and document set. The individual passport or logbook should be used to verify manufacturing data, operating time, repair history and remaining resource for the particular unit. Aviamisto can confirm the available execution and supply terms for 246-3914-000.