8A-1516-20

Hinged tail shaft section 8A-1516-20

8A-1516-20 is a hinged section of the tail transmission shaft assembly used in Mi-series helicopter tail rotor drive systems. The component forms part of the 8A-1516-000 shaft line and works between rigid transmission sections inside the tail boom. Its role is to transfer torque toward the tail gearbox while allowing the shaft system to tolerate angular displacement, vibration and structural movement that occur during helicopter operation. In the full tail drive system, this hinged section works together with straight shaft sections, supports, couplings, flanged joints and gearbox interfaces.

Torque transfer and angular compensation through 8A-1516-20

The 8A-1516-20 section is used where the tail shaft line requires both torque transmission and limited compensation of alignment changes. Unlike a purely rigid shaft section, a hinged section helps the transmission line absorb angular mismatch caused by airframe flex, vibration, installation geometry and dynamic loading. During flight, the tail boom is not a completely static structure, and the drive line must continue rotating reliably under changing loads. The hinged construction helps maintain continuous torque delivery to the tail gearbox and tail rotor without imposing excessive stress on connected shaft elements.

8A-1516-20 in the 8A-1516-000 shaft assembly

The 8A-1516-20 is not a complete tail drive shaft by itself. It is one component within the larger 8A-1516-000 tail transmission shaft system. This distinction is important for procurement and maintenance, because the same helicopter shaft line may include several straight and hinged sections with different positions and interfaces. The hinged section links rigid shaft elements and helps preserve correct operation of the complete assembly. When supplied for maintenance, it may be ordered as an individual spare part or included as part of a broader tail shaft service kit.

Installation role of the hinged 8A-1516-20 section

The 8A-1516-20 section is installed through flanged interfaces with associated hardware according to the applicable shaft assembly documentation. Correct mounting is important because tail drive shaft alignment affects vibration level, bearing load, joint life and gearbox input behavior. During installation, attention should be paid to flange condition, mating surfaces, hardware completeness, balance marks, hinge movement and general shaft-line alignment. A damaged or incorrectly installed hinged section may cause abnormal vibration, uneven loading or premature wear of adjacent transmission components.

Application of 8A-1516-20 on Mi-series helicopters

The 8A-1516-20 hinged section is used on core and modernized variants of the Mi-8 helicopter family. Typical applicability includes Mi-8, Mi-8MT, Mi-8MTV, Mi-17, Mi-171 and Mi-14 helicopters, depending on the aircraft documentation and installed tail drive system. Because these aircraft can differ by modification, overhaul history and transmission configuration, interchangeability should always be checked through the parts catalog and actual installation layout. A visually similar shaft section should not be treated as suitable unless the designation, assembly role and mounting interfaces match.

Identification and ordering of 8A-1516-20

The section may be referenced under several equivalent designations: 8A-1516-20, 8А-1516-20, 8A151620 and 8A.1516.20. These references identify the same hinged tail transmission shaft section, but an order should still confirm the helicopter type, shaft assembly number, condition, completeness and documentation. If the section is requested as part of a complete kit, the scope of included flanged hardware and related installation parts should be specified separately. For overhaul supply, the 8A-1516-000 passport, spare parts manifest and installation notes are useful for matching the component to the target aircraft.

Product Type: Hinged section of the tail transmission shaft
Designation: 8A-1516-20
Alternative Designations: 8А-1516-20, 8A151620, 8A.1516.20
Function: Torque transmission with compensation of angular misalignment, vibration and structural displacement
Application / Where Used: Mi-series helicopter tail rotor transmission systems
System / Installation Area: Tail rotor drive line between intermediate gearbox and tail gearbox
Compatible Aircraft / Equipment: Mi-8, Mi-8MT, Mi-8MTV, Mi-17, Mi-171, Mi-14 helicopters
Assembly Role: Component of 8A-1516-000 tail drive shaft system
Transmission Path: Tail boom shaft line transmitting torque toward the tail gearbox and tail rotor
Mounting: Flanged interface with associated hardware, included in full shaft kit depending on supply scope
Operational Speed, System: Up to approx. 2589 rpm
Compensation Function: Flex, vibration and structural displacement compensation
Material: Structural alloy component
Condition: As applicable
Documentation: 8A-1516-000 passport, spare parts manifest, installation notes, aircraft maintenance documentation

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