The design of the Mi-2 helicopter is a turbine development of the Mi-1, in which, by installing two small gas turbine engines above the fuselage, the entire area of the cabin was freed for payload. The creation of a new aircraft became known in the fall of 1961, and the first Mi-2 appeared two years later with two 400-liter Izotov GTD-350 gas turbines. from. each mounted side by side above the cab.
Main goals
The aircraft was designed to perform the same tasks of transporting lightweight cargo as the Mi-1 was engaged in. The passenger version could transport 7 people and a pilot. In the role of a rescue aircraft, the Mi-2 helicopter accommodates four stretchers and a paramedic. The vessel is capable of carrying cargo weighing up to 700 kg. As a flying crane or for rescue operations, the aircraft can be equipped with a dorsal hook for a suspended load weighing up to 800 kg or a winch above the cabin door, which can lift up to 150 kg. The fourth main application that distinguishes the Mi-2 helicopter is agricultural operations, for which it can be equipped with tanks placed on both sides of the cabin, capable of holding 450 kg of dry chemicals or 500 liters of liquid. For other tasks, cargo tanks can be replaced with additional fuel tanks.
History of creation
The Mi-2 helicopter (see photo in the review) was produced at the WSK factory in Mielec in Poland. After negotiations begun in January 1964, WSK received exclusive rights to manufacture the aircraft and its engines. It was assumed that it will replace the Mi-1 in military aviation and will be especially valuable to Aeroflot as an ambulance and air taxi. Some Mi-2s are believed to have been delivered to the UAR, from where they probably ended up in Israel.
In the mid-fifties, the Mil bureau decided to increase the performance of the Mi-1 by developing its turbine version. For this, two new gas turbine engines with a free Isotov GTD-350 turbine were selected. With a weight of half the mass of the previous reciprocating internal combustion engines, the two GTD-350s were 40% more powerful. They are mounted side by side above the fuselage, which significantly increases the available space of the cockpit and improves the characteristics of the Mi-2 helicopter. Such a power plant allowed to change the rotational speed of the screw, maintaining constant engine speed.
The prototype of the aircraft was called B-2, and then was renamed Mi-2. The helicopter took off for the first time in September 1961. It had the same rotor, gear and tail unit as the Mi-1. After preliminary tests, a metal tail rotor was adopted (it was wooden for the Mi-1), and then in 1965 a new rotor hub appeared, borrowed from the Mi-6.
Since Soviet factories were fully engaged in the production of Mi-8 and other heavy Mi-series helicopters, an agreement was reached with WSK-Swidnik to manufacture and further develop the Mi-2 in Poland, which began in 1964. The first Polish Mi-2 before flew in November 1963, and after testing was completed in 1965, large-scale production began. The first production Mi-2 helicopter was equipped with 400 l engines. s., but since 1974 this parameter has been increased to 450 liters. from. The use of fiberglass in the main rotor, tail rotor and stabilizer simplified production and increased productivity.
For civilian and military purposes, various versions of the Mi-2 were built. The helicopter, which was in service with the Polish Air Force, was equipped with missile launchers and air-to-ground missiles, which were launched from guides on the sides of the fuselage.
Modifications
- Mi-2: a helicopter of the standard civilian version, convertible passenger or freight transport, a pollinator (called the Bazant), a training aircraft for aerial photography and photogrammetry, or a carrier with external sling and electric hoist.
- Mi-2B: basic model with updated navigation aids and an electric system without anti-icing rotor blades. The weight of the passenger version was 2300 kg, and the freight version - 2293 kg.
- Mi-2D Przetacznik: military air command post with radio communications, encryption and telephone equipment.
- Mi-2P: standard eight-seat passenger helicopter convertible into a full-load one with external suspension and an electric winch.
- Mi-2P: agricultural version for conventional or ultra-small spraying and spraying. Tanks with a capacity of 500 l of liquid or 375 kg of dry chemicals each were hung on both sides of the fuselage, and the 14th sprayer boom with 128 nozzles was attached. Weight without cargo - 2,372 kg.
- Mi-2 Platan: mining helicopter.
- Mi-2RL: air ambulance and search and rescue version of the Mi-2, equipped with an electric lift.
- Mi-2RM Anakonda: version of the search and rescue helicopter Mi-2P for naval use with an electric hoist through the port of the side door, designed for two people and air-boats. Built 9 units for the Polish naval aviation.
- Mi-2Ro: military intelligence modification.
- Mi-2RS Padalec: chemical and bacteriological intelligence helicopter.
- Mi-2C: Medevac air ambulance, equipped to transport four stretchers, an accompanying, and two patients in a sitting position.
- Mi-2SZ: training helicopter with double control.
- Mi-2T: military transport.
- Mi-2URN: 1973 version of the Mi-2US, but with two Mars 2 launchers, each of which holds 16 57-mm S-5 unguided missiles for direct air support or armed reconnaissance.
- Mi-2URP Salamandra: anti-tank model of the Mi-2 helicopter of the 1976 version with four AT-3 guided missiles (“Baby” 9M14M) on pylons and four more in the cargo compartment; later models were equipped with four Strela 2 missiles.
- Mi-2URPG Gniewosz: similar to Mi-2URP, but with four SA-7 anti-aircraft missiles (9M32 Strela).
- Mi-2US: a combat helicopter equipped with a 23 mm NS-23KM gun from the left side of the fuselage, two machine guns on the sides and two 7.62 mm machine guns in the rear.
- Mi-2FM Kajman: version for photogrammetry. 2 units produced.
- Mi-2X Chekla: radiation reconnaissance helicopter and smoke screen director.
- UMi-2Ro: training reconnaissance option.
Mi-2MSB
On the Ukrainian modification of the Mi-2MSB installed engines AI-450M "Motor Sich" with a capacity of 465 liters. from. with 27% less fuel consumption and 25 kg less weight. Helicopter avionics has also been updated. The variant is equipped with pylons with eight 80-mm B8W8MSB rocket launchers and automatic grenade launchers. Due to the fact that the pylons pass through the rear windows without changing the design of the fuselage, machine guns with ammunition from the helicopter cockpit can be installed outside.
Additional 7.62 mm machine guns can be located in the windows of the helicopter. In addition, under the tail boom, along with the IR jamming system, a signal rocket launch device is located . These elements provide partial protection against infrared-guided anti-aircraft missiles, which pose the greatest threat to military helicopters.
Technical description of the Mi-2 helicopter
The supporting system is a three-blade screw with hydraulic vibration dampers. The blade profile is NACA 230-12M. The blades do not add up. The rotor brake is installed. The main shaft of the screw is driven by the gearbox of each engine. The transmission includes a three-stage main gearbox, intermediate and tail.
The turbine speed reduction coefficient for the main rotor is 1: 24.6, for the tail rotor - 1: 4.16. The main gearbox provides the drive for auxiliary systems and power take-off for the rotor brake. The freewheel disconnects the rotor from the failed engine, allowing self-rotation.
Initially, each blade had the typical design of all Mil helicopters, consisting of 20 connected sections attached to a light alloy spar with a trailing edge of honeycomb aluminum and coated with a sheet of light alloy. Later, WSK-PZL-Swidnik developed more advanced rotor blades based on an extruded duralumin spar with plastic sections and a coating.
Hydraulic reinforcement system for cyclic and common pitch control; the variable installation angle, controlled by the common pitch lever, has a horizontal stabilizer.
The duralumin fuselage is connected by spot welding or rivets. It consists of three main nodes - the bow, central and tail beams; load-bearing elements are reinforced with alloy steel.
Chassis
Mi-2 - a helicopter with a fixed gear tricycle landing gear with a tail support. A double wheel is located in front and one wheel is mounted in the main part. Oil-pneumatic shock absorbers are installed on all supports, including the tail. The main shock absorbers are able to cope with both normal workloads and potential earth resonance. The main tires have dimensions of 600x180 mm at a pressure of 4.41 bar. Nasal - 400x125 mm in size, pressure 3.45 bar. The main wheels are equipped with pneumatic brakes. Metallic aviation skis are optional.
Power point
The engine of the Mi-2 helicopter is a 313-kW turboshaft Isotov GTD-350 of Polish construction. Two such gas turbine units are mounted side by side above the cockpit. The only 600 liter rubber fuel tank is located under the passenger compartment floor. On both sides of the helicopter, it is possible to mount additional external tanks with a volume of 238 liters. A gas station is located on the right side of the housing. The volume of oil is 25 liters.
Accommodation
Usually one pilot is on the left side of the cockpit. The air-conditioned cabin provides space for 8 passengers - oriented back to back benches for 3 people each with two additional side seats on the starboard side, one behind the other. All passenger seats can be dismantled for transportation of up to 700 kg of cargo. Access to the cabin is through hinged doors on each side in front of the cab and aft on the left. In emergency situations, the pilot's sliding window is squeezed out. The rescue modification provides space for 4 stretchers and orderlies, or 2 stretchers and 2 seated patients. In the training version, the seats are located nearby and there is a dual control. Mi-2 - a helicopter with standard heating, ventilation and air conditioning systems.
Systems
The interior is heated by air heated by the engine. For ventilation in cold weather, the temperature of the air rises in the heat exchangers.
The hydraulic system has a pressure of 65 bar and is designed to strengthen the lever of the cyclic and general pitch. The flow rate of the hydraulic fluid is 7.5 l / min. The tank is ventilated. The pneumatic system has a pressure of 49 bar and is designed to operate the brake.
Power supply is provided by starters-generators driven by two 3 kW kW STG-3 engines, as well as from a 3-phase 16 kVA alternator with a voltage of 208 V. 24 V DC power supply is provided by two 28 Ah lead-acid batteries. The main and tail rotors, the windshield are equipped with an electrical anti-icing system. The air intake is heated by air drawn from the engine.
Avionics
Standard elements include two PV / HF transceivers, a gyrocompass, a radio compass, a radio altimeter, an intercom system and a blind flight panel. On some military modifications, bow and tail warning radars are installed.
Equipment
The agricultural version of the helicopter on each side of the fuselage is equipped with a tank with a total capacity of 1000 liters of liquid or 750 kg of dry chemical substance, and either an injector stand at the rear of the cabin on both sides, or a spray of dry chemicals on each tank. Spray capture bandwidth is 40–45 m.
In the rescue version, an electric winch with a carrying capacity of 120 kg is installed. The cargo ventral hook can be mounted to lift suspended loads up to 800 kg in weight.
The smoke curtains director attaches additional long pipes to the exhaust pipes to which fuel is supplied. The pilot's windshield is equipped with an electric wiper. In addition, a freon fire extinguishing system is installed in the engine compartments and the main gearbox compartment, which is activated automatically or manually.
Mi-2 helicopter: technical specifications
- Height - 3.3 m.
- Length - 11.4 m.
- The diameter of the screw is 14.5 m.
- Take-off weight - 3550 kg.
- The weight of an empty helicopter is 2350–2372 kg.
- The volume of fuel is 600 liters, with additional tanks - 838 liters.
- The lifting speed is 4.5 m / s.
- Cruising speed and speed at an altitude of 190–194 km / h, near the ground - 210 km / h.
- Ceiling - 1700 m (static), 4000 m (dynamic).
- Flight range - 355 km, maximum - 620 km.
Mass production of the Mi-2 was completed in 1993. Most of the over 5450 manufactured helicopters were exported to the USSR and other countries of the Warsaw Pact. Nevertheless, the Mi-2, whose operation is still ongoing in more than 20 countries, has a chance to be revived in the Mi-2A model, developed by the Moscow Helicopter Plant and Rosvertol OJSC.