The Mi-4 helicopter became the calling card of the Soviet Army and the personification of many construction projects in the 50s and 60s. The creation of the machine was carried out in a short time, since the command of the armed forces understood the growing role of helicopter units in modern realities. This was especially evident during the conflict in Korea, where early models of US helicopters took part.
Despite the haste of creation, the car was not a failure. Moreover, there were practically no birth defects in her. This allowed the Mi-4 to remain in service in a number of countries until the early 90s of the last century.
History of creation
The development of the Mi-4 helicopter began in the first half of the 50s, when the technical specifications for a universal machine suitable for use in the army and civil service were formulated. Since army service was considered a priority, the project received the designation VD-12 (V-12 is also found) - a landing helicopter for 12 people.
According to the instructions, the helicopter was single-rotor, so the designers were faced with the problem of the layout of the power plant. At that time, the domestic industry produced the only engine option for helicopters - the radial AI-26. But the engine power (580 hp at takeoff) was clearly not enough for the heavy VD-12. Even two such engines could not correct the situation.
For this reason, the developers paid attention to the large-scale two-row “star” ASH-82, widely used in domestic aircraft. By order of OKB A.D. Shvetsova created a special version of the engine, adapted for installation on a helicopter. The new engine provided power of 1530 hp. at an altitude of 1550 m, which was quite enough for a VD-12 type vehicle.
The Mi-4 prototype was tested in mid-spring 1952, during which the pilots encountered the rotor flutter effect.
The problem was solved quite quickly by installing special weights on the blades. According to the standard scheme for Soviet aviation, the helicopter was put into service even before the test results were received.
Official tests were carried out on transport and landing versions of the vehicle. Moreover, the vehicles had small arms on board, represented by the NUV-1 mobile installation, located under the lower forward part of the fuselage. The installation contained a large-caliber (12.7 mm) TKB-481 machine gun and ammunition consisting of a belt with 200 rounds of ammunition.
The production of Mi-4 aircraft was carried out at the Kazan Helicopter Plant from 1953 to 1966. In total, more than 3,200 copies were made. In addition, production licenses were transferred to China, where the helicopter was built under the designations HarbinZ-5 and Xuanfeng. Chinese cars were built until 1979; in total, about 550 copies were assembled and exported.
Interesting Facts
- The development, flight testing and introduction of the helicopter into mass production were carried out in record time - within one year.
- The Mi-4 became the first production helicopter equipped with built-in weapons. A mobile NUV-1 rifle mount with a TKB-481M heavy machine gun was installed in the ventral gondola.
- The Mi-4 was the first helicopter in the USSR used for crane installation work.
- In 1955, two Mi-4s made a flight of more than 5,000 km from Moscow to the North Pole-5 polar station.
- In 1956-1965, the Mi-4 set 8 international records, including lifting a load weighing 2000 kg to a height of 6017 m and weighing 1000 kg to a height of 7575 m.
- In 1957, for the first time in the USSR, a helicopter autopilot began to be installed on serial Mi-4s.
- In 1958, at the World Exhibition in Brussels, the Mi-4 was awarded a gold medal and a diploma.
Modifications
The first production version was the Mi-4A, which received its designation based on test results and began entering service with ground units already in 1953. For the needs of naval aviation, a modification of the Mi-4S appeared, which had a set of equipment for flights over land and sea. The helicopter retained its wheeled landing gear, since the float landing gear was not tested. According to other sources, the Mi-4S designation was for a luxury passenger version of the vehicle, intended for transporting dignitaries.
The civilian model of the helicopter received the designation Mi-4P, and began entering the domestic market of the USSR in 1954.
The vehicle allowed the simultaneous transportation of 10 passengers and cargo weighing up to 200 kg. It was this machine that stood at the origins of the development of passenger helicopter transportation in the Soviet Union. For example, helicopters were used to deliver passengers from Moscow airports to the central station on Khodynka.
At the same time, the first experiments began to create an agricultural helicopter designed for spraying chemicals. Designated in a number of sources as the Mi-4SKH could lift up to 1600 liters of liquid fertilizers and up to 1000 kg of powder fertilizers. However, the operation of such versions was considered unprofitable and the vehicles were quickly replaced by agricultural modifications of the Ka-15 and Ka-26.
Instead of fertilizers, there could be a supply of water or a special mixture (1000 l) and a device for spraying it (a water barrel) on board. The cargo compartment could accommodate a fire crew of 8 people. The helicopter was designated Mi-4L and was used to fight forest or steppe fires. Later, the ineffective barrel was abandoned and the vehicle was used to disembark crews.
In 1958, the Mi-4PS version appeared, designed for search and rescue operations at sea and land. Additional radio equipment and additional fuel tanks (two pieces) were installed on board, holding 900 liters of gasoline. The cargo compartment had a winch and a landing lifeboat. On the outside of the vehicle there were hangers for containers with paint used to paint the water surface during rescue operations.
Due to the increased set of radio equipment, an operator was added to the crew, located in the cargo compartment.
A little later, the helicopter began to use inflatable cylinders, which made it possible to land on water. The wheeled chassis remained unchanged. The first tests of the Mi-4PS revealed a lot of shortcomings that limited the scope of application. After correcting the comments, the helicopter was built serially.
The fall of 1959 is the date of birth of the version of the air minesweeper based on the Mi-4, adapted for landing on water and refueling without landing on the deck of a ship. The vehicle did not have small arms and was equipped with a fuel tank reduced to 550 liters. The helicopter was built in small batches.
Around the same time, an anti-submarine version of the Mi-4M appeared, equipped with submarine detection capabilities. On board the vehicles there was a supply of depth charges, instead of which sonar buoys could be used. The helicopter was built serially and was in service with the Navy until the end of the 70s.
By the mid-60s, the Mil Design Bureau decided to introduce the helicopter to foreign markets. For this purpose, a modification of the Mi-4ME is being created, which differs in the range of equipment for detecting submarines.
The Mi-4M anti-submarine helicopter became the base for the Mi-4T bomber and torpedo bomber. The torpedo was placed under the fuselage in a special container. Due to the expanded fuel reserve, it was possible to achieve an increase in flight range, which is an important parameter for naval vehicles. In the bomber version, the helicopter could lift up to 520 kg of anti-submarine bombs of various models.
In 1967, the first Soviet attack helicopter, the Mi-4AV, was created, equipped with side trusses for mounting weapons.
The helicopter was created as a platform for testing the weapon concept of the future Mi-24. The vehicle could use unguided rockets (in cassettes) or Phalanx anti-tank missiles, which had the ability to adjust the flight path. To work with weapons, the helicopter was retrofitted with sighting equipment.
There was no additional armor for the cabin or power plant. Vehicles previously delivered to the army were converted into this version; in total, at least 200 copies were converted. On the basis of helicopters exported to Czechoslovakia, the Mi-4V was created, which was distinguished by the installation of weapons on farms.
Surviving copies
| Surviving examples of the Mi-4 multi-purpose helicopter | |||
| Modification | Board number | Location | Image |
| Mi-4 | CCCP-48983 | State Aviation Museum (Kyiv) | |
| Mi-4PS | CCCP-35277 | Leading branch museum of the history of civil aviation | |
| Mi-4T | CCCP-14844 | Inta, Russia | |
| Mi-4A | 12013 | Belgrade, Serbia | |
| Mi-4A | 314 | Lubuskie Muzeum Wojskowe, Poland | |
| Mi-4A | 785 | Luftfahrzeugen der Nationalen Volksarmee, Germany | |
| Mi-4 | 2139 | Flugausstellung Hermeskeil, Germany | |
| Mi-4B | 0538 | Letecke muzeum Kbely, Czech Republic | |
| Mi-4A | 27 | Museum of Hungarian Aviation, Hungary | |
| Mi-4 | USSR-31449 | Riga Aviation Museum, Latvia | |
Description of design
The two-story fuselage of the Mi-4 helicopter is built on the basis of a metal frame made up of frames and stringers. A metal sheathing of variable thickness is riveted on top. Structurally, the fuselage is divided into a main section and two beams - tail and end. Connections are detachable.
The engine load frame is attached to the first frame of the main section. Inside the main section of the Mi-4 vehicle there is a crew cabin, a cargo compartment and separate rooms for installing tanks, a main rotor gearbox and radio equipment.
The cargo compartment of the Mi-4 is equipped with loading doors located in the rear section. The width of the opening corresponds to the size of the compartment, which allows you to place large cargo and some types of cars and motorcycles (GAZ-69 all-terrain vehicle or a pair of M-72 motorcycles with side trailers).
The maximum volume of cargo transported by the machine is 16 cubic meters. m.
Additionally, there is a side door and three side windows. The cargo version was equipped with a manual winch and rigging devices. The transport version of the Mi-4 is equipped with removable seats designed to transport 12 people (overload up to 16). The ambulance is equipped with attachment points for 8 stretchers and an additional seat for an attendant.
A gondola is installed under the floor of the cargo compartment, which serves as a location for batteries and antennas. It is allowed to operate the helicopter with the nacelle removed and a protective sheet installed in place.
Two Mi-4 crew workstations with duplicate controls are located above the cargo compartment. The cockpit has an increased glass area and sliding side doors. The doors have blister-shaped glass to improve visibility. From the cabin you can enter the cargo compartment through a hatch in the floor. The hatch is equipped with a folding ladder.
The pilot's workplace is equipped with an oxygen device. The ambulances have eight portable oxygen devices, depending on the number of wounded or sick people being transported. To heat the cabin and cargo compartment of the Mi-4, a gasoline heater equipped with a network of air ducts is used. Additional members can be added to the crew of the vehicle - a navigator, a mechanic, an operator of additional equipment. In this case, one of the workplaces is equipped in a gondola.
The power plant on the Mi-4 vehicles is a 14-cylinder two-row “star” ASh-82N with carburetor power.
The engine is equipped with a release clutch and an axial fan for cooling the cylinders. Part of the air flow is diverted through channels to cool the oil radiators and gearbox housing. Air is supplied through the side air intakes.
Hot air is exhausted through grilles and controlled flaps on the hood of the machine. The Mi-4 engine is equipped with a two-speed mechanical supercharger, allowing it to develop 1,700 hp on takeoff. An exhaust system with free flow of gases was used, as well as an option with flame arresters.
The crankshaft of the Mi-4 engine is connected to the gearbox by a special shaft equipped with torsional vibration dampers. The shaft has a spline connection that compensates for changes in the installation points of the units. There is a clutch at the gearbox input that allows the screw to operate in free rotation mode.
The gearbox provides power take-off to drive the helicopter hydraulic oil pumps. A shaft is routed from the gearbox to the tail rotor drive. The drive has an additional gear that provides a change in the angle of the shafts (arising from the layout of the machine).
The main rotor of the Mi-4 helicopter has four blades of trapezoidal cross-section.
The blade profile is variable. The design of the power set is combined, consisting of wooden ribs and stringers fixed to the steel pipe of the spar. The blade covering is made of canvas and plywood. Later, machines began to use an all-metal propeller with a honeycomb filling, which had an increased service life.
The pushing tail rotor has three blades equipped with a pitch adjustment mechanism. The design of the regulator allows for reverse thrust. The blades are made of wood and have a metal frame.
The fuel supply on Mi-4 vehicles (grade B95/130 gasoline) is located in a single soft, protected tank with a capacity of 1000 liters, located behind the gearbox. The fuel is supplied by a pump; an additional electric valve is installed, which serves to dilute the oil in winter.
In the cargo compartment of the Mi-4 there is a standard place for installing a standard barrel with a capacity of 275 liters. The barrel is connected to the fuel supply line through a separate pump. As fuel is consumed, the tank is filled with inert gas. Additionally, the transmission includes a brake mechanism that locks the screws when the engine starts.
The Mi-4 helicopter uses a four-post fixed landing gear, which provides taxiing capabilities. The front rotary struts of the machine are mounted on the frame of the power unit, equipped with gas-oil shock absorbers and pneumatic tires measuring 400*150 mm. The wheels turn spontaneously, there is no forced control.
Braking mechanisms are not used.
The main racks with an extended track are equipped with pneumatic tires of size 700*250 mm and brakes with pneumatic drive. The design of the Mi-4 rack contains shock absorbers and tanks for storing compressed gas reserves. Additionally, the machine has a tail support that protects the helicopter from damage during rough landings. The support has a gas-oil shock absorber.
The electrical equipment of the Mi-4 helicopter is built using a single-wire circuit with the negative pole supplied to the body. DC sources with a voltage of 28 volts are the GSR-3000M generator located on the engine and batteries. Electricity distribution is carried out by three panels, the circuits are protected by bimetallic circuit breakers.
The standard equipment of the vehicle includes a radio station, a radio compass, a radio altimeter and an internal intercom.
To combat ice on Mi-4 vehicles, a special liquid (a mixture of alcohol and glycerin) is supplied to the blades and windshields of the cockpit. The liquid supply is in a special tank with a capacity of 28 liters.
Mi-24 losses
- 02/03/2002 in Chechnya - 1 helicopter.
- 03/20/2003 2 helicopters crashed during an exercise.
- In 2003 in Ukraine - 1 helicopter.
- In the same year, on August 26 in Chechnya - 1 helicopter.
- After 23 days, two Mi-24Vs collided at the Chernigovka airfield.
- This November there was 1 helicopter in Chechnya.
- In August 2007 (Amur Region) - 1 helicopter.
- February 3, 2009 (Saratov region) - 1 helicopter.
- 2010, July 13 (Dagestan) - 1 helicopter.
- November 29, 2011 (Belarus) – 1 helicopter.
- August 26 of the same year (Primorsky Territory) - 1 helicopter.
- 2012 (Kenya) - 3 helicopters belonging to the Ugandan army.
- September 8, 2012 (Botlikh) - 1 helicopter.
Application and comparison of characteristics
Immediately after the Mi-4 entered service, they were demonstrated at air festivals in Tushino. The first combat experience for helicopters was the uprising in Hungary in 1956. Exported vehicles took part in conflicts between India and Pakistan, in Ethiopia and Iraq. The vehicles delivered to Vietnam were used during combat operations in the 60-70s.
Attack and transport helicopters managed to take part in the initial stage of the entry of Soviet troops into Afghanistan. However, by this time the vehicle was outdated and was quickly replaced by modern Mi-8 and Mi-24, equipped with turboshaft power plants. During the 80-90s, army helicopters supplied for export were written off. As of 2016, a number of Mi-4 vehicles were listed in flying condition in the DPRK army.
Civilian vehicles were used to transport passengers and various cargoes. In a number of Asian republics of the USSR, Mi-4 helicopters were used to deliver mobile teams of medical workers. The cars flew around remote villages and provided various medical services to the population. Along with the personnel, there was equipment on board.
The helicopter's carrying capacity made it possible to use the machine for delivering building structures.
For example, it was the Mi-4A that was used in the construction of the trolleybus line between Simferopol and Yalta. The equipment was used in civil aviation until 1988. The remaining helicopters were written off after the Mi-4A crashed in the Chita region, which killed 8 people.
A comparison of the technical characteristics of the Mi-4 with American analogues from Sikorsky clearly shows the advantage of the domestic machine in terms of speed and take-off weight. The N-16 model has an increased flight range due to its low weight and the use of a low-power engine. In the latest series, the N-34 helicopter began to be equipped with turboshaft engines. OKB Mil took the path of creating new helicopters, initially adapted for the installation of such engines.
| Parameter | Mi-4A | Sikorsky H-19 | Sikorsky H-34 |
| Length, mm | 16800 | 12730 | 17280 |
| Height, mm | 4400 | 4267 | 4850 |
| Main screw diameter, mm | 21000 | 16150 | 17070 |
| Maximum weight, kg | 7600 | 3660 | 6350 |
| Flight speed, km/h | 226 | 178 | 198 |
| Passenger capacity, persons | 16 | 12 | 16 |
| Flight range, km | 465 | 667 | 293 |
| Ceiling, m | 5500 | 4755 | n.d. |
N-34 helicopters are among the American aircraft that were officially purchased by the USSR. In the early 60s, two copies were purchased by order of N.S. Khrushchev.
The Mi-4 helicopter holds the record for the speed of introduction into production, which is a little over a year.
For the Soviet helicopter industry and the Mil Design Bureau, the machine became a breakthrough design in many respects. Thanks to the experience gained, transport and army vehicles were developed that had no analogues in world practice.
The helicopter became a pioneer in a number of applications. For example, the Mi-4 was used for crane installation work - when installing power lines or building oil drilling rigs. One can only regret that this car was preserved as a monument in only two settlements.
Operators
Military
- USSR - were widely used in the armed forces of the USSR, where the Air Force formed helicopter regiments, each of which had 60 Mi-4s.
- Afghanistan - 18 Mi-4s were in service from 1963 to 1997
- Albania - 22 Mi-4 (since 1957 and 37 Z-5 (since 1967); withdrawn from service in 2005
- Algeria
- Angola
- Bangladesh - Mi-4 played an important role in the Bangladesh War of Independence
- Bulgaria
- Burkina Faso - 4 Mi-4s were in service from 1985 to 1989
- Cambodia
- Cameroon - 1 Mi-4
- China - 545 Harbin Z-5 were produced (licensed copy of the Mi-4); used in the army, air force and naval aviation
- Cuba
- Czechoslovakia
- GDR
- Egypt
- Finland - 3 Mi-4s were in service from 1962 to 1979
- Guinea-Bissau
- Ghana - 1 Mi-4
- Hungary
- India
- Indonesia
- Iraq
- Laos
- Mali - 4 Mi-4
- Mongolia
- DPRK
- Poland
- Romania
- Sierra Leone
- Somalia
- PDR Yemen
- Syria
- Sudan
- Vietnam
- Yemen
- Yugoslavia - 25 Mi-4; withdrawn from service in the late 1970s
Civil
- USSR
- China
- Czechoslovakia
- Romania
- Mongolia
CONSTRUCTION AND KINEMATIC DIAGRAMS OF HELICOPTER TRANSMISSION
The transmission of a single-rotor Mi-8 helicopter with RV (4.2.1) includes: main gearbox (GR) 2; brake HB 3; tail shaft 4; intermediate gearbox (IR) 5; intermediate shaft 6; gearbox RV 7; oil-air radiator fan drive shaft 1. The power for the drive of the air and air cooler, the units that ensure the operation of the helicopter systems (hydraulic and oil system pumps, electric generator, compressor and tachometer sensor), comes from the right and left engines through the GR.
The GR is installed on the helicopter on the struts of the gearbox frame in the upper part of the helicopter. PR is designed to change the direction of power transmission. The RV gearbox changes the direction of power transmission from the PR and reduces the speed of the steering shaft.
The Hughes OH-6A light helicopter uses a KKS transmission. Characteristic of this helicopter is the placement of the engine and air-oil radiator 2, the use of a supercritical shaft 5 with a damper 4 and the absence of PR. The output of the gas jet to the rear part of the fuselage 7 reduces its aerodynamic drag, and the drive of the oil cooler fan directly from the main shaft and the elimination of the PR significantly reduce the total weight of the transmission.
Armament of Tu-128
The aircraft's armament included four R-4/K-80 air-to-air missiles developed by the Bisnovat Design Bureau. Typically these were two R-4R missiles, which had semi-active radar guidance and were fixed on external pylons, as well as two R-4T missiles, which were placed on internal pylons and had infrared guidance. The aircraft's armament was modernized in the 60s; it was equipped with R-4TM and R-4RM missiles.
The military use of the Tu-128 provided for several options. One of them involved identifying targets, and targeting the interceptor was carried out using ground stations and Tu-126 AWACS aircraft. Interacting with this complex, the Tu-128 could operate in a semi-autonomous mode. From the reconnaissance officer, the navigator operator received the course and composition of the target; further search by the interceptor was carried out independently.
On December 12, 1963, the USSR Ministry of Defense assigned the name of the aviation missile interception complex, which included:
- Tu-128 aircraft;
- R-4T and R-4R air-to-air missiles;
- Radar RP-S "Smerch".
Serial production of the Tu-128 aircraft lasted until 1970. Over the entire period, 188 interceptors were released. In 1971, 10 pilot training machines were created, four of which were converted from fighter aircraft. This modification was named Tu-128UT. In its design, an additional front cabin appeared in place of the radar. Further projects of the Tupolev bureau with the names Tu-138 and Tu-148 were not further developed.
