Helicopter: WSK Mi-2URP (NATO: Hoplite)
USSR / Poland
In the second half of the 1950's at the Mikhail Mil's 329 (OKB 329) Experimental and Construction Bureau work on significant improvements of the multi role Mi-1 helicopter, started. Among many changes, the replacement of the piston engine with new turbo shaft propulsion was considered. Assumptions envisaged the same dimensions, while the passenger capacity was increased to eight persons. Among many concepts, the most promising "classic" (single main rotor with steering rotor) configuration, powered with two turbo shaft engines, coupled with common reduction gear, was chosen.
The engine compartment was placed over the cockpit. In that way, additional passenger and cargo space was achieved. The twin engine lay-out increased the in-flight safety in case of damage. The possibility of landing with only working one engine was also thought of. The design was named the W-2. The only problem remaining was the lack of an appropriate engine.
In 1959 - 1960, the designing of the new engine, at the Klimov Construction Bureau in Leningrad, started. The lead designer was S.P. Isotov. The construction team carried out the design of the GTD-350 small turbo shaft engine, sampling the American Allison turbo shaft engine. In 1963, the engine passed through state tests, however giving way to technical parameters.
By the end of 1960, the Mil Experimental and Construction Bureau received an official order for the new helicopter. Both military and civil aviation were interested in the design. In designing the W-2, the use of Mi-1 type parts was planned. In practice it became impossible. By the end of September 1961, the W-2 prototype performed hovering and low speed flight. A month later, the state tests started. The test flight had no problems and the W-2 appeared to be a very successful design. The military authorities were interested in the transport-ambulance version and civil aviation authorities were interested in the agricultural type.
In September 1963, the state commission decided to introduce the now named, Mi-2 helicopter, into mass production.
In September 1962, the machine was shown to the Polish state delegation. It was during the time when considerations of Mi-2 production in Poland, started. By the end of 1963 at the Świdnik Communication Equipment Manufacture, initial preparation started. In January 1964 an official agreement of handing over the Mi-2 and the GTD engine with reduction gear licence production, was signed. The airframe was produced in Świdnik, the engine in Rzeszów.
By the end of August 1965, at the factory airfield in Świdnik, the first Mi-2, assembled from Soviet made parts, was flown and in November of the same year, the first all-Polish production machine took to the air. Mass production ended just at the beginning of the 1090's. In total, 5418 helicopters (with the majority exported to the Soviet Union) were produced. A few were exported to ten countries, others were bought by Polish military and civil aviation. The number of foreign users increased because of many re sales.
The trials of helicopter modernisation were carried out several times, both in Poland and the Soviet Union, resulting in developing some interesting improvements. Still the unsolved problem was a lack of an appropriate high-output turbo engine. Mikhail L. Mil and his deputy, M.N. Tischchenko tried many times to encourage Soviet engine designers to carry out a design of a small turbo shaft engine. Their appeals received no response.
Poland carried out the Mi-2 helicopter's engine improvement, by using the American Allison 250 turbo shaft. The new helicopter was named PZL Kania (kite). Its performance increased significantly.
The first versions utilised by the Polish army were: 1. The Mi-2T - transport version, with the possibility of a quick conversion to an ambulance, (it could carry 700kg or 6-8 passengers), the Mi-2P - the six seat, passenger version, the Mi-2Sz (Mi-2U, UMi-2), with duel controls and used for blind flying training.
At the turn of 1960's and 1970's, Polish military specialists analysed the use of helicopters by the American army in Vietnam. The American experiences revolutionised opinions over the use of helicopters on the battlefield. They appeared not only superb, airborne transport machines, but could also play very effective, close support or tank destroyers roles.
In 1970, Polish military specialists carried out the analysis of arming the Mi-2. As a result of this, one 23mm, lower port side mounted, fixed cannon, and four side-hanging machine guns were applied (the Mi-2US), or two unguided rockets launchers with 32 missiles (the Mi-2URN). Similar tests were carried out also in the Soviet Union.
At the same time, trials of converting the MI-2 helicopter into a tank destroyer, by equipping it with four, wire guided, anti-tank, Soviet "Malyutka M" missiles launchers were carried out.
The new version was named the Mi-2URP (the AAR "Armed, Antitank Rockets") The firing tests took place in 1972 and at the beginning of 1973. In 1977, the helicopters were used during the Warsaw Pact manoeuvres.
The Mi-2URP was armed with one 23mm cannon mounted on the lower port side, two movable, 7,7,62mm machine guns in the cargo compartment's sliding windows and four 9M14M "Malyutka" antitank guided missiles, placed on four rails attached in pairs to both sides of the fuselage. Four extra missiles were stored in the fuselage.
The missile was guided on target, by the observer using the "three point eye-missile-target method". To improve guidance, trials of applying a telescope were carried out, but the vibrations made the target observation difficult. The observer's eye and hand commanding the missile still remained the best way of guidance.
At the beginning of the 1980's, the tests of the air target fighting Mi-2URS version started. It was armed with four infra-red guided "Strzała M" missiles (arrow M, removable anti aircraft missiles complex). Again the helicopter's vibrations caused problems with the practical use of this type of armament. In such situations, the Mi-2URS was not introduced into service.
By the end of 1980's, some of the Mi-2URP's were equipped with the "Strzała M" (named also the "Gad" or reptile) missiles hanged under the "Malyutka M" anti tank missiles launchers. This way, the latest Mi-2URP-G version appeared.
The first Mi-2 came in service with the Polish Air Force in 1967. Two years later the inventory was increased to 34 machines. In 1985, 270 examples of different versions were in service with the Polish Air Force. Several machines still remain in service today.