246-3904-000 Series 01

Hub and matched blade set

The rotor includes one 246-3914-000 tail rotor hub and one matched set of three 246-3925-00 tail rotor blades. The hub provides three blade attachment positions, transfers torque from the tail gearbox and transmits pitch-control movement to the blade set. The blades generate aerodynamic lateral thrust as their collective pitch changes through the helicopter tail rotor control system.

The hub and blades form a balanced rotating system. Selection and installation must therefore be based on the complete assembly designation, matched blade-set records and individual passports. Similar appearance or another 3904- or 3914-family number does not establish interchangeability. The approved aircraft maintenance documentation governs installation, balancing, locking and final acceptance.

Passport-confirmed technical characteristics

The passport specifies a three-blade pusher rotor with a nominal diameter of 3.908 m. Diameter tolerance is +0.005 m and −0.008 m. Maximum product mass is 121.5 kg, with the passport tolerance of +0.75 kg and −0.78 kg. The documented blade designation is 246-3925-00. Approved lubrication materials and service procedures are defined by the operating manual and passport; substitutions should not be made without the applicable maintenance instructions.

The passport references installation on the applicable 240 and 80MT product modifications and on 171, AMT, 172 and MTV configurations with the specified engine and moving-stop control-system arrangements. It also lists the Mi-35MS configuration. Final applicability must be checked against the exact aircraft modification, installed engine, control-system configuration and current technical documentation.

Delivery set and accompanying parts

The standard passport composition identifies one 246-3914-000 hub, one matched set of three 246-3925-00 blades, the tail rotor and blade-set passports, and six 8-3914-041 blade fastening bolts. It also lists mounting parts not installed in the assembled hub: one 8-3914-502 rod nut, one 8-3914-503 washer, six 3.2 × 40.029 cotter pins, one 3.2 × 32.029 cotter pin and 0.5 m of KO-1 locking wire.

The operational SPTA section includes an 8-120 measured oil-filling device, three 8-200 transfer devices, one 8-300T technological cap and the individual operational set of tools and accessories with its list. Checking devices 6360-504 and 6360-714 are identified as customer-request items and are not stated as unconditional standard supply. Final delivered completeness is confirmed against the passport and quotation for the specific unit.

Resource control and ordering

For the documented mainstream configurations, the passport states 1,000 operating hours to the first overhaul and a 1,000-hour overhaul interval. The calendar limit is seven or eight years depending on the aircraft configuration. The assigned service life is 3,000 operating hours for the listed 240, 80MT, 171/AMT and 172/MTV configurations. The Mi-35MS line has its own passport limits and must be evaluated separately. All resource values remain subject to the individual passport, preservation history, operating records and technical condition.

Before ordering, specify the aircraft modification, required quantity, end-user documentation requirements and whether the complete standard delivery set is required. Serial numbers, blade-set matching, preservation date, operating time and remaining life are confirmed from the documents of the particular 2025 unit offered.