Experimental-design Bureau of Mil was created in 1947. By this time the team of the design Bureau completed a draft of single-screw aircraft. The first flight of the helicopter was completed in 1948. He successfully passed flight and state tests: the machine is well hung, demonstrated high maneuverability and satisfactory stability. In 1950 mass production of first helicopter of the country began. It was named MI-1.
MI-1 helicopter immediately found wide application in the national economy: for agricultural avia chemical works, exploration from the decks of the ice and whaling ships, estimation of reserves of forests, maintenance of geological parties, salvation fishermen etc.
In 1951, the Bureau has received the task to create the helicopter which according to its data particularly as for the capacity and the ceiling could surpass the best analogues of the time. In the shortest period of time the team of the design Bureau developed a new helicopter and began its preparation for serial production at the end of 1952. It was a well-known transport helicopter MI-4 equipped with piston engine AL-82B, helicopter variant of well-known engine of A.A. Shvetsov design. After the successful completion of state tests the MI-4 was put into operation.
The MI-4 was the first helicopter with a rear loading hatch and ladder for loading into the fuselage of different wheeled vehicles. Currently such layout scheme (firstly proposed by the Bureau) has become common for vehicles.
In the process of developing the MI-4 was a significant step forward in the development of the construction of main units. For the first time there were included hidro boosters in a helicopter controls. In particular, it was the first flying machine with completely irreversible booster running.
The most difficult problem was the creation of a reliable rotor blades. Resource of blades was reduced from 150 to 2000-2500 hours with a simultaneous increase of their reliability. Also research conducted on increase of a resource of other major vital units of the car. The MI-4 was one of the most reliable helicopters in the world.
In addition to the main transport, there appeared passenger, sanitary and agricultural options. One of the modifications of the helicopter is equipped with a float chassis. With special outdoor suspension MI-4 was used as a flying crane.
In 1953 the design Bureau started development of a transport helicopter for transportation of 6 tons of cargo over a distance up to 600 km. The First flight of the new single-rotor helicopter scheme MI-6 with two turboprop engines took place in 1957. In the same year during a test flight it was set the first world record - lifted cargo of 12 tons. In 1962 was lifted a weight of 20.1 tonnes. From 1959 to 1964 the MI-6 of serial production set of 12 world records.
Using the autopilot, an optional navigation equipment, electrothermal, de-icing system, introduction of the crew Navigator allowed to use the MI-6 at any time of day or night and in any weather. In fact it became the first all-weather helicopter and since 1964 successfully operated in the economy of our country.
MI-6 is the world's first helicopter crossed abroad speed of 320 km/hour.
MI-6 is the world's first helicopter of serial production equipped with two turboprop engines with free turbine. Its layout is recognized as a classic. It was the most perfect helicopter far ahead on the development of their contemporaries.
In June 1960 the MI-10 made its first flight. During the tests it was found that the helicopter can transport cargoes of up to 20 meters a height of 3,5 meters width up to 5 meters (in case of cross form of a cargo is up to 10 m) weighing 12 tons at the distance of 250 km and weighing 15 tons is at shorter distances.
In subsequent years the design Bureau held fruitful work on the creation of medium and light helicopters with turbine engines. Later it was decided to apply twin engines power unit to ensure the smooth continuation of flight at failure of one of engines. The first helicopter MI-8 with two turboprop engines designed by OKB S.P.Izotov in 1965 entered series production.
In 1960 the Bureau began to design light helicopter on the basis of the MI-1 twin engines designed by S.P.Izotov. The creation of such a helicopter as MI-2 was a step forward in the development of machines of this class. Two turbine schemes for light helicopters first used for the MI-2 received today the total recognition. He has significant advantages as compared to the MI-1 as the payload and the speed. This machine moved as ones in a class MI-4 by their data while it belonged to the class MI-1 by size and the take-off weight.
In 1967 the largest ever existed helicopters B-12 rose in the air. In one of the test flights he lifted a weight of more than 40 tons. The helicopter was built by a transverse scheme with the wing reverse narrowing. By estimations of experts the appearance of such experimental helicopter confirmed the possibility of transition to a building rotary-wing aircraft with a takeoff weight of 100 tons.
Further there were created the multi-purpose MI-17 helicopters, successfully used in the national economy of our country and the helicopter MI-26 is the most powerful serial helicopter designed to fulfill the unique installation works.