Mikhail Mil, who must rank with Igor Sikorsky as one of the world's leading exponents of rotorcraft design, was a contemporary of Nikolai Kamov at the TsAGI (Central Aero and Hydrodynamic Institute) during the 1930s. Given charge of his own design bureau in 1947, he became responsible for the first Soviet helicopter to go into quantity production. Originally designated GM-1, the Mi-1 prototype was completed and flown in September 1948 and was a compact machine with a fully-enclosed metal-skinned fuselage. It was built to a single main rotor configuration, with a small anti-torque rotor at the rear - a layout to which Mil, like Sikorsky, has adhered firmly ever since. The Mi-1 made its public debut at the Tushino Air Display in 1951, by which time it was already in production and service with the Soviet armed forces.
Subsequent production of the Mi-1, both in the Soviet Union and in Poland, has been extensive. In addition to those built for the Soviet armed forces, military Mi-1's have also been supplied to the DOSAAF and the air forces of Albania, Afghanistan, Cuba, Czechoslovakia, Finland, Iraq, Poland, Syria, the United Arab Republic and the Yemen. A wide range of duties has included those of observation, liaison, rescue, ambulance and training. Wide use was also made of the Mi-1 by Aeroflot and by civil authorities in the Soviet Union and other Soviet bloc countries. The standard Mi-1 seats 3 passengers in addition to the pilot; variants include the Mi-1T, which carries only 2 passengers, the Mi-1U which is a dual-control trainer and the Mi-1NKh, a utility model for such duties as freight and mail carriage, ambulance and agricultural operations. Other models to appear were the 1956 Mi-3, a slightly heavier version with a 4-blade main rotor, wider cabin and additional flight aids; and the Mi-1 Moskvich, a refined version of the standard Mi-1 produced for Aeroflot.
Polish production began with the standard Mi-1 late in 1955, this being built at the WSK works at Swidnik under the designation SM-1 with a licence-built version of the AI-26V engine. Several of the Mi-1's supplied to foreign air forces were Polish-built, and subsequent versions included the SM-1W (pilot and 3 passengers), SM-1WS (2-stretcher ambulance), SM-1WZ (agricultural) and SM-1WSZ (dual-control trainer). Production of the Mi-1/SM-1 is thought to have been phased out around 1963 in favour of the later turbine-powered developments, but large numbers of these useful little machines are still active in many parts of the world.
K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968
The Mi-1, initially designated GM-1 (Gelikopter Mil, or Mil helicopter) was the first production Russian helicopter to enter service with the Soviet armed forces. Development of this aircraft started shortly after the end of the war and the first of three prototypes flew in September 1948; delivery of the production models began in 1951.
The Mi-1 was a four-seat general purpose helicopter. It was replaced in the final production runs by the Mi-1T, a three-seater with different operational equipment. A dual control trainer version was designated Mi-1U.
Once military requirements had been met by a production run of several hundred, the Mi-1 was also widely adopted for a great variety of civil tasks, such as air ambulance duties, fish-spotting or whaling, ice patrol in polar regions, highway patrol and for carrying mail.
An agricultural variant, designated Mi-1NKh, could carry 400kg or 500 liters of chemicals in two hoppers at the sides of the fuselage. In 1961, the Mi-1 Moskvich passenger version was developed for Aeroflot, with an all-metal rotor, hydraulic controls, better cabin soundproofing and night flying or all-weather instrumentation. In 1956, a prototype (erroneously indentified in the West as Mi-3) was also evaluated. This had a four-blade rotor and various other external modifications, such as two lateral stretcher panniers, but it did not enter production.
Numerous Mi-1s were exported to allies of the Soviet Union, for both civil and military use, and many are still in service. From 1955, they were also produced in Poland by WSK-Swidnik, with the designation SM-1, and were built in various different versions. Most of the Polish helicopters were for export. The SM-1 provided a model for development of the SM-2, which had a stretched fuselage to accommodate five, and was produced from 1961. Production of the Mi-1 ended in 1961 in the Soviet Union and in 1965 in Poland.
G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984
First project of OKB, this was (remarkably, in view of widespread prior rotary-wing efforts) first Soviet helicopter of now-classic layout with single main rotor anti-torque tail rotor. Original designation GM-1 (Gelikopter Mil); design begun September 1947 and prototype completed exactly a year later. Three-blade main rotor, blades based on A-15 and related autogyros, mixed steel/ply/fabric NACA-230 profile, fully articulated hub with friction dampers, normal speed 232 rpm. Fuselage light alloy, except for welded steel tube basis of mid-section housing engine with crankshaft horizontal and cooling fan, driving through angle box to transmission with centrifugal clutch and rotor brake. Four-seat cabin with left/right hinged doors. Fuel in welded aluminium tank 240 lit behind engine and, from about 40th production, provision fox external supplementary tank of 160 lit on left side. Monocoque tail boom and pylon for tail rotor with three wooden blades. Fixed nosewheel-type landing gear with brakes, plus long rear skid to protect tail rotor.
First flight M.K.Baikalov (ex-Bratukhin) Sept 1948. Both first two GM-1 lost, second killing Baikalov after weld failure in tail-rotor bearing. Project taken over by Mark Gallai and V.V.Vinitskii, followed in summer 1949 by NII testing by G.A.Tinyakov and S.G.Brovtsyev, reached height 6800m and speed 190.5km/h. Yak-100 delayed so production authorized as Mi-1. Eight took part in 1951 Aviation Day display.
Civil and military variants including ambulance with left/right stretcher pods externally, agricultural Mi-1NKh with two 500 lit hoppers (note: solids only, liquid being weight-limited to smaller capacity) and many specialized models, with optional pontoon landing gear. From about 40th called Mi-1M with 0.32m adjustable stabilizer (tailplane). From 1957 new blades with extruded steel-tube spar. By this time basic model called Mi-1T, pilot and two passengers plus radio and fluid de-icing; also dual Mi-1U trainer. In 1961 Mi-1 Moskvich with all-metal blades of almost untapered plan, hydraulic controls and better standard of equipment and soundproofing. Name dropped and improvements (initially at request of Aeroflot) mostly standardized. Variant with four-blade rotor (erroneously dubbed Mi-3 in West) remained prototype. From 1954 main blades bonded metal, production transferred to Poland as SM-1, "some thousands" built to 1965. Last example withdrawn 1983. ASCC name "Hare".
Bill Gunston "The Osprey's Encyclopedia of Russian Aircraft", 2000
Mil Mi-1 (NATO reporting name Hare) was the first helicopter designed by the talented Mikhail Leontyevich Mil who was Technical Officer of the Soviet air force's First Rotorcraft Squadron for a time during World War II.
The Soviet version made its maiden flight in 1948 while a Polish version flew in 1956. It was a dramatic success for Mil who had only established his bureau a year earlier. The Mi-1 was first seen by the West at Tushino in 1951, by which time it had been in quantity production and was in service with the Soviet air force.
It consists of a cabin for three passengers with a radial seven-cylinder engine driving the rotor through an angle gearbox. A 2.5m shaft runs from the gearbox to the tail rotor. The main rotor has friction dampers and is fully articulated through hinges.
Like Soviet equipment during World War II, the Mi-1 is designed to operate at very low temperatures and has anti-freeze sprays for not only the rotors but also the windscreen.
The Mi-1 has been produced in a vast number of configurations. These include the Mi-3 a four-bladed heavy version with a wider cabin and additional flight aids. The Mi-3 appeared in 1956, but two years earlier the Mil bureau produced an ambulance version. This was interesting since the patients were carried on stretchers in streamlined pods on either side of the fuselage. Pipes connected the pods to the fuselage to allow the temperature to be controlled.
The Mi-1T carries two passengers, while the Mi- 1U is a dual-control trainer. The Mi-1NKh (Narodnoye Khozyaistvo) is a utility model used for freight and mail carriage. In an agricultural role it can be fitted with spraying bars and two 250- litre tanks.
Poland began building the Mi-1 in late 1955 at the WSK works at Swidnik where it was fitted with an AI-26V engine and designated SM-1. An SM-2 entered service in 1961 and is a larger machine with a longer nose. It can accommodate four passengers or a third stretcher inside besides the two in the external pods.
Production has probably ceased in favour of more modern turbine-powered machines, but the Mi-1 is still widely used by Soviet bloc countries and their allies in civil and military roles.
Bill Gunston "The Illustrated Encyclopedia of Commercial Aircraft", 1980