Mi-8

The Mil Mi-8 (NATO: "Hip") is a medium twin-turbine helicopter, first flown in 1961 and introduced into Soviet service in 1967. It is the world’s most-produced helicopter, with over 17,000 built and production continuing as of 2025. The Mi-8 serves in transport, command, gunship, and reconnaissance roles, and is the basis for several other helicopter families, including the Mi-14 and Mi-17/171.

The Mi-8 was conceived as a successor to the piston-powered Mil Mi-4, leveraging turbine engine technology from the Mil Mi-6. Initially proposed by Mikhail Mil in 1959, the Soviet military was hesitant, favoring the Mi-4. Mil pitched the Mi-8 as an upgrade with turbine engines, leading to approval in 1958. The prototype, designated V-8, was based on the Mi-4 but featured a larger cabin and a single AI-24 2,010 kW (2,700 shp) Soloviev turboshaft engine. The V-8 flew in June 1961. After Nikita Khrushchev’s approval, influenced by exposure to the U.S. S-58 helicopter, the twin-engine design was prioritized, with the Sergei Isotov Design Bureau developing purpose-built TV2-117 engines. The V-8A prototype, equipped with two 1,120 kW (1,500 shp) Isotov TV2 engines, flew on August 2, 1962, marking the first Soviet helicopter with dedicated gas turbine engines. Serial production began in Kazan in 1965 and later in Ulan-Ude in 1970.

The early models were built on the original Mi-8 design with TV2-117 engines. The Mi-8 variants can be classified as follows:

• First-Generation Variants (1960s–1970s): Mi-8T, Mi-8TV, Mi-8P/PS/S, Mi-8PPA etc.
• Second-Generation Variants (1970s–1990s): Mi-8MT, Mi-8MTV, Mi-8MTKO, Mi-8AMT, Mi-8AMTSh, Mi-8MSB-V etc.
• Third-Generation Variants (1990s–Present): Mi-8MTV-5, Mi-171, Mi-171A2, Mi-171Sh, Mi-171A3, Mi-17V-5, CH-178 etc.

The Mi-8’s baseline design (e.g., Mi-8T) features:

• Airframe: Aluminum construction with a bus-like fuselage, tail boom, and non-retractable tricycle landing gear.
• Engines: Two Isotov TV2-117A turboshafts (1,120 kW/1,500 shp each), with a limiter to restrict power for rotor compatibility.
• Rotor: Five-bladed main rotor (aluminum alloy) and a three-bladed tail rotor (right side on Mi-8).
• Capacity: Up to 24 troops or 4,000 kg payload.
• Performance: Max speed 250 km/h, range 425–480 km, service ceiling 4,500 m.
• Features: De-icing system, optional armor, and polyurethane foam-filled fuel tanks for survivability

More information:

• AirVectors: Mi-8 Variants
• Wikipedia: Mil Mi-8
• GlobalSecurity: Mi-8 Hip Variants
• Aircraft Recognition Guide: Mi-8 Family