|First flight||20 September 1948|
The Mil Mi-1 (
All early variants seated pilot in front and two passengers behind him, in common cabin. The first production variant was Mi-1, quickly replaced by improved Mi-1T, that carried extra operational equipment including full radio and blind-flying instruments, and had more reliable engine AI-26V. The next basic variant was the Mi-1A of 1957, with further increased reliability and provisions for one 160 l external fuel tank.
A new major variant, Mi-1M in 1957 introduced an enlarged cabin and the more powerful AI-26VF engine, which allowed the accommodation of three passengers on a bench behind the pilot. Cabin height increased from 1.22 to 1.26 m and width from 1.01 to 1.2 m. A noticeable difference was horizontal bottom windows line instead of slanted, with bigger rear side windows, and a less pointed fuselage nose. It could also be fitted with two external side capsules for the injured or mail. There were trials of an armed anti-tank variant Mi-1MU carried in 1961, being the first Soviet attack helicopter, but it did not enter production due to having a small payload and the cessation of production of the basic variant.
Well over 1,000 of all variants were built in the USSR, including a proportion of dual-control trainers (with U suffix): Mi-1U, TU, AU, MU, with the instructor seated behind a trainee. 15 were produced in Moscow in 1950, 30 in Kazan in 1952–1953, 597 in Orenburg in 1954–1958 and 370 in Rostov in 1956–1960. In 1956 license-production of the four-seat model began in Poland, at
Several international records in its class were broken with the Mi-1 or SM-2.