Operating temperature range for mi 2 helicopter. Helicopters

Helicopters of Russia and the world (video, photo, pictures watch online) occupy an important place in the overall system of the national economy and the Armed Forces, honorably fulfilling the civil and military tasks assigned to them. According to the figurative expression of the outstanding Soviet scientist and designer ML. Mile, “our country itself is, as it were, “designed” for helicopters.” Without them, the development of the boundless and impassable spaces of the Far North, Siberia and the Far East is unthinkable. Helicopters have become a familiar element of the landscape of our grandiose construction projects. They are widely used as a vehicle, in agriculture, construction, rescue service, military affairs. When performing a number of operations, helicopters are simply irreplaceable. Who knows how many people's health was saved by the helicopter crews who took part in the aftermath of the Chernobyl accident. The lives of thousands of Soviet soldiers were saved by combat "turntables" in Afghanistan.

Before becoming one of the main modern transport, technological and combat vehicles, Russian helicopters have come a long and not always smooth path of development. The idea of ​​lifting into the air with the help of a main rotor originated among mankind almost earlier than the idea of ​​flying on a fixed wing. In the early stages of the history of aviation and aeronautics, the creation of lift by "screwing into the air" was more popular than other methods. This explains the abundance of rotary-wing aircraft projects in the 19th and early 20th centuries. Only four years separate the flight of the Wright brothers' plane (1903) from the first lift of a man into the air by helicopter (1907).

The best helicopters were used by scientists and inventors, they hesitated for a long time which method to prefer. However, by the end of the first decade of the XX century. less energy-intensive and simpler in terms of aerodynamics, dynamics and strength, the aircraft took the lead. His successes were impressive. Almost 30 years passed before the creators of helicopters finally managed to make their devices workable. Already during the Second World War, helicopters went into mass production and began to be used. After the end of the war, the so-called "helicopter boom" arose. Numerous firms began to build samples of new promising technology, but not all attempts were successful.

Combat helicopters of Russia and the United States It was still more difficult to build than an aircraft of a similar class. Military and civilian customers were in no hurry to put a new type of aviation equipment on a par with the already familiar aircraft. Only the effective use of helicopters by Americans in the early 50s. in the war in Korea convinced a number of military leaders, including Soviet ones, of the advisability of using this aircraft by the armed forces. However, many, as before, continued to consider the helicopter "a temporary delusion of aviation." It took another ten years until helicopters finally proved their exclusivity and indispensability in performing a number of military tasks.

Russian helicopters have played a big role in the creation and development of Russian and Soviet scientists, designers and inventors. Their significance is so great that it even gave rise to one of the founders of the domestic helicopter industry, Academician B.N. Yuriev to consider our state as the "birthplace of helicopters." This statement, of course, is too categorical, but our helicopter pilots have something to be proud of. These are the scientific works of the school of N.E. Zhukovsky in the pre-revolutionary period and the impressive flights of the TsAGI 1-EA helicopter in the pre-war years, the records of the post-war Mi-4, Mi-6, Mi-12, Mi-24 helicopters and the unique Ka family of coaxial helicopters, modern Mi-26 and Ka -32 and much, much more.

The new Russian helicopter is relatively well covered in books and articles. Shortly before his death, B.N. Yuryev began to write the fundamental work "The History of Helicopters", but managed to prepare only the chapters relating to his own work in 1908 - 1914. It should be noted that insufficient attention to the history of such an aviation industry as helicopter construction is also characteristic of foreign researchers.

Military helicopters of Russia in a new way illuminating the history of the development of helicopters and their theories in pre-revolutionary Russia, the contribution of domestic scientists and inventors to the global process of development of this type of equipment. A review of pre-revolutionary domestic works on rotary-wing aircraft, including previously unknown ones, as well as their analysis, were given in the corresponding chapter in the book "Aviation in Russia", prepared for publication in 1988 by TsAGI. However, its small size significantly limited the size of the information provided.

Civil helicopters in their best colors. An attempt has been made to cover the activities of domestic helicopter industry enthusiasts as fully and comprehensively as possible. Therefore, the activities of leading domestic scientists and designers are described, as well as projects and proposals are considered, the authors of which were significantly inferior to them in terms of their knowledge, but whose contribution could not be ignored. Moreover, in some projects, which generally differed in a relatively low level of development, there are also interesting proposals and ideas.

The name of the helicopters denoted significant qualitative changes in this type of equipment. Such events are the beginning of a continuous and systematic development of helicopter projects; the construction of the first full-scale helicopters capable of taking off the ground, and the beginning of mass production and practical use of helicopters. This book chronicles the early history of helicopter engineering, from the concept of propeller lift into the air to the creation of the first helicopters capable of taking off from the ground. A helicopter, unlike an airplane, a flywheel and a rocket, does not have direct prototypes in nature. However, the screw that creates the lifting force of the helicopter has been known since ancient times.

Small Helicopters Despite the fact that propellers were known and there were empirical prototypes of helicopters, the idea of ​​using a main rotor to lift into the air did not become widespread until the end of the 18th century. All the rotorcraft projects being developed at that time remained unknown and were found in the archives many centuries later. As a rule, information about the development of such projects has been preserved in the archives of the most prominent scientists of their time, such as Guo Hong, L. da Vinci, R. Hooke, M.V. Lomonosov, who in 1754 created an "airfield machine".

Private helicopters in a short time were created literally dozens of new designs. It was a competition of the most diverse schemes and forms, as a rule, one- or two-seat apparatus, which had mainly an experimental purpose. The military departments were a natural customer for this expensive and complex equipment. The first helicopters in different countries were assigned to communications and reconnaissance military vehicles. In the development of helicopters, as in many other areas of technology, two lines of development can be clearly distinguished - but the dimensions of the machines, that is, the quantitative one, and the line of development of the qualitative improvement of aircraft within a certain size or weight category that almost simultaneously arose.

Site about helicopters which contains the most complete description. Whether the helicopter is used for geological exploration, agricultural work or for the transport of passengers - the determining role is played by the cost of an hour of operation of the helicopter. A large share of it is depreciation, that is, the price divided by its service life. The latter is determined by the resource of the aggregates, r, e. by their service life. The problem of increasing the fatigue strength of blades, shafts and transmissions, main rotor bushings and other helicopter units has become a paramount task that still occupies helicopter designers. Nowadays, a resource of 1000 hours is no longer a rarity for a serial helicopter, and there is no reason to doubt its further increase.

Modern helicopters comparing the combat capabilities of the original video has been preserved. The image found in some publications is an approximate reconstruction, and not entirely indisputable, carried out in 1947 by N.I. Kamov. However, a number of conclusions can be drawn on the basis of the archival documents cited. Judging by the test method (suspension on blocks), the "airfield machine" was undoubtedly a vertical take-off and landing apparatus. Of the two methods of vertical lift known at that time - with the help of flapping wings or by means of a main rotor - the first seems unlikely. The protocol says that the wings moved horizontally. In most flyers, they are known to move in a vertical plane. A flywheel whose wings oscillate in a horizontal plane with an installation angle that changes cyclically, despite repeated attempts, has not yet been built.

The best helicopter design is always directed to the future. However, in order to more clearly imagine the possibilities for further development of helicopters, it is useful to try to understand the main directions of their development from past experience. What is interesting here, of course, is not the prehistory of helicopter construction, which we will only briefly mention, but its history from the moment when the helicopter, as a new type of aircraft, was already suitable for practical use. The first mention of a device with a vertical propeller - a helicopter, is contained in the notes of Leonardo da Vinci dating back to 1483. The first stage of development stretches from the model of a helicopter created by M. V. Lomonosov in 1754, through a long series of projects, models, and even devices built in kind , which were not destined to take to the air, until the construction of the world's first helicopter, which in 1907 managed to get off the ground.

The fastest helicopter in the outlines of this machine, we recognize the schematic diagram of the most common single-rotor helicopters in the world now. B. I. Yuryev managed to return to this work only in 1925. In 1932, a group of engineers, headed by A. M. Cheremukhitsnch, built a TsAGI 1-EA helicopter, which reached a flight altitude of 600 m and lasted 18 m / w in the air which was an outstanding achievement for that time. Suffice it to say that the official flight altitude record, set 3 years later on the new Breguet coaxial helicopter, was only 180 m. At this time, there was a pause in the development of helicopters (helicopters). A new branch of rotorcraft, gyroplanes, came to the fore.

The new Russian helicopter, with a greater load on the wing area, came face to face with the then new spin problem of loss of speed. It turned out to be easier to create a safe and sufficiently perfect autogyro than to build a helicopter helicopter. The main rotor, freely rotating from the oncoming flow, eliminated the need for complex gearboxes and transmissions. The articulated attachment of the main rotor blades to the hub used on gyroplanes provided them with much greater strength, and stability for the gyroplane. Finally, stopping the engine was no longer dangerous, as was the case with the first helicopters: by autorotating the gyroplane, it was easy to land at low speed.

Large helicopters for landing marines from ships determined the further development of the military helicopter industry as a transport and landing. The landing by S-55 helicopters of the American troops at Inchon during the Korean War (1951) confirmed this trend. The size range of transport and assault helicopters began to be determined by the dimensions and weight of ground vehicles used by the troops and which had to be airlifted. Therefore, the carrying capacity of the first transport helicopters in foreign armies was 1200-1600 kg (the weight of a light military vehicle used as a tractor and related guns).

USSR helicopters correspond to the weight of light and medium tanks or corresponding self-propelled chassis. Whether this line of development will be completed in such a range of dimensions depends on the ever-changing military doctrine. Artillery systems are mostly being replaced by rockets, which is why we find demands from the foreign press as well. Power did not lead to an increase in payload. Indeed, but to the technical level of that time, the weight of propellers, gearboxes for the entire apparatus as a whole increased with an increase in power faster than the lifting force increased. However, when creating a new useful and even more so new for national economic application, the designer cannot put up with a decrease in the achieved level of weight return.

Soviet helicopters, the first samples, were created in a relatively short time, since the specific gravity of piston engines always decreased with increasing power. But in 1953, after the creation of the 13-ton Sikorsky S-56 helicopter with two 2300-hp piston engines. with the size range of helicopters in the Zapal was interrupted and only in the USSR, using turboprop engines. In the mid-fifties, the reliability of helicopters became much higher, therefore, the possibilities of their use in the national economy also expanded. Economic issues came to the fore.

Helicopter Mi-2 is the first light domestic helicopter with a gas turbine engine, designed specifically for civilian use to replace helicopters Mi-1 . The OKB received an order for its development in May 1960, and in January 1961. a model of a helicopter was presented, which received the designation IN 2, which it was decided to build in two versions: passenger and agricultural; their first flights respectively took place in September 1961. (test pilot G.V. Alferov) and in December 1961. (test pilot V.I. Anopov). After lengthy state tests, which confirmed the high efficiency of the use of helicopters Mi-2 for agricultural work, September 20, 1963 it was decided to mass-produce helicopters Mi-2 which in January 1964 it was considered expedient to carry out in Poland at a helicopter plant PZL-Swidnik, where the license for serial production was transferred. The first helicopter built in Poland Mi-2 made its first flight on December 4, 1965; serial production continued until 1992, more than 5250 helicopters were built in total Mi-2 for civil and military use, most of which were exported to many countries (Bulgaria, Hungary, Germany, Egypt, Iraq, Libya, Czechoslovakia, North Korea, etc.).

As a helicopter replacement Mi-1 , the new helicopter significantly surpassed it in flight speed and payload, and the power plant of two gas turbine engines provided it with superiority over foreign helicopters of the same class, which at that time were produced only with single engines. Due to good flight and operational characteristics, helicopters Mi-2 widely used in helicopter sports competitions; by helicopter Mi-2 in 1963 and 1965 two international speed records were set 253.818 and 269.38km/h on the base 100km. Helicopters Mi-2 mass-produced in Poland in 24 different modifications, the main of which were the following:

• Mi-2- passenger helicopter for transportation of 8 passengers;
• Mi-2T- transport, for the transportation of goods weighing up to 700kg in the cockpit or 800kg on an external suspension; an ambulance helicopter was produced to transport four patients on stretchers and an orderly;
• Mi-2R- search and rescue, with an electric winch with a carrying capacity 120kg;
• Mi-2UPN- reconnaissance helicopter with weapons from two blocks of 16 NAR C-5 caliber 57mm;
• Mi-2URP- anti-tank helicopter with 4 ATGMs 9M14M "Baby" on pylons;
• Mi-2US- fire support helicopter with a gun caliber 23mm or with installations with machine guns caliber 7.62mm on pylons and in the cockpit;
• Mi-2KM- carrier-based multi-purpose helicopter;
• Mi-2M- upgraded version of the helicopter Mi-2, equipped with two GTD-350P takeoff power 331kw; made its first flight on July 1, 1974, was produced in the following versions:

  Agricultural helicopter for spraying liquid or dry chemicals;
  - training and sports helicopter;
  - helicopter for aerial photography;
  - Helicopter for monitoring the state of the environment.

• PZL-Swidnik "Kania" - modernization of the helicopter Mi-2 with improved fuselage contours, enlarged cabin, two gas turbine engines Allison 250-C20B takeoff power 314kW, improved equipment and improved flight characteristics; maximum takeoff weight is limited to 3550kg. The first prototype helicopter SR-PSA, converted from Mi-2, made its first flight on June 3, 1979, certified in Poland on October 1, 1981. and in the USA on FAR 29 February 21, 1986. 4 experimental helicopters and 7 serial helicopters were built: in passenger, transport, agricultural, sanitary, search and rescue and reconnaissance versions.

DESIGN. A single-rotor helicopter with a tail rotor, two gas turbine engines and a tricycle landing gear.

The semi-monocoque fuselage consists of three parts: a nose with a cockpit, a central one with a passenger cabin and a tail boom with a controlled stabilizer span of 1.85 m and an area of ​​0.7 m 2 .

The cockpit is single-double, in most variants one pilot is in the seat on the left, in the training version the pilot and cadet are placed side by side, with dual controls. In the passenger cabin with dimensions of 2.27 x 1.2 x 1.4m, equipped with an air conditioning system, 8 passengers are accommodated on two triple seats facing each other in flight, and two seats on the starboard side. When transporting goods, the passenger seats can be removed. In the sanitary variant, the cockpit has mounts to accommodate four patients on a stretcher with an orderly or two on a stretcher and two on the seats; access to the cockpit is through two doors that open on hinges, and to the passenger cabin - through a large door measuring 1.1 x 0.78 m from the port side.

The landing gear is tricycle, non-retractable, the main supports are shaped, with oil-air shock absorbers and brake wheels with dimensions of 600 x 180 mm and a pressure of 0.43 MPa, the nose gear is self-orienting, with twin wheels with dimensions of 400 x 125 mm and a pressure of 0.34 MPa. Installation of metal skis is possible.

The main rotor is three-bladed, with hinged blades and hydraulic dampers. The blades are all-metal, rectangular in plan, with a pressed spar and a NACA 230-12M profile and a chord of 0.4m.

The tail rotor with a diameter of 2.7 m, two-bladed, with all-metal blades of a rectangular shape in plan. The main and tail rotor blades are equipped with an electric anti-icing system. For the first time in the practice of domestic helicopter construction, torsion bars were used in the tail rotor hub.

The power plant consists of two GTD-350 turboshaft engines with a take-off power of 298 kW each, developed under the direction of S.P. Izotov and produced under license in Poland. The gas turbine engines are installed next to the top of the fuselage in front of the gearbox with protruding air intakes and twin nozzles on the sides of a common fairing with a fan for cooling the engine masporadiator and gearbox.

The fuel system includes one fuel tank with a capacity of 600 liters under the cabin floor, it is possible to install two additional tanks on the sides of the fuselage with a capacity of 238 liters each; The oil system consists of an oil tank with a capacity of 25 liters and an oil cooler with a fan for cooling.

The transmission consists of a three-stage main gearbox BR-2 with a freewheel, an intermediate gearbox and a tail rotor gearbox. The main gearbox has a gear ratio to the main rotor shaft 1:24.6, tail rotor gearbox - 1:4.16m.

Booster control system, with hydraulic boosters in the channels of longitudinal and transverse control and common pitch control and spring loading mechanisms, driven by a hydraulic system with a working pressure of 6.5 MPa and a capacity of 7.5 l / min.

The pneumatic system with a working pressure of 4.9 MPa provides the drive of the brakes of the main wheels.

The alternating current electrical system is powered by two starter-generators STG-Z with a power of 3 kW, driven by engines, and a three-phase current generator with a power of 16 kW and a voltage of 208V. The DC system is powered by two 26Ah lead-acid batteries.

The equipment is standard, including MW and HF radio stations, a gyrocompass, a radio compass, a radio altimeter and a SPU. On a number of military options in the bow and on the tail boom there are radar warning receivers.

The agricultural variant is equipped with a chemical spraying system with tanks on the sides of the fuselage with a total capacity of 1000 liters for liquid chemicals and a spray boom 14m long, with 128 nozzles, spraying chemicals in a strip 40-45m wide or spraying dry chemicals with a total weight of 750 kg contained in two containers with sprayers .

The search and rescue version is equipped with an electric winch with a lifting capacity of 120 kg, and the transport version is equipped with a hook for external suspension of loads weighing up to 800 kg. On the variant for monitoring the environment, thermal imaging equipment of the company "ASA" is installed.

Armament. In reconnaissance version Mi-2URN on the sides of the fuselage there are pylons for two blocks of 16 NAR each C-5 caliber 57mm, and in the anti-tank version Mi-2URP 4 ATGMs are suspended on pylons 9M14M "Baby" or 9MZ2 "Strela-2". Option Mi-2US for fire support can be armed with a cannon NS-23KM caliber 23mm installed on the left side of the fuselage, and additionally two blocks of 16 NAR C-5 caliber 57mm or cannon and 6 machine guns caliber 7.62mm(two on the pylons on the sides of the fuselage and two in the cockpit).

E.I. Ruzhitsky "Helicopters", 1997

Photo

	OKB Mil, Mi-2
	OKB Mil, Mi-2
	OKB Mil, Mi-2
	OKB Mil, Mi-2
	OKB Mil, Mi-2
	OKB Mil, Mi-2

Takeoff of MI-8 in the air cushion zone.

We have already found out how, in principle, a helicopter is controlled, and how it works. And today we will bring some clarity to the question of what role the pilot plays in all this. What governing bodies are given to him to solve, in general, a difficult task, which is helicopter control

Second - track control.That is, a change in flight direction. It is carried out using the tail (tail) propeller by changing its thrust (that is, changing the total pitch of the tail propeller). If the helicopter is a twin-rotor scheme (without a tail rotor), then by changing the torque of one of the screws. I have already spoken about this.

The third type - lateral control. it helicopter control on a roll. The roll is created by tilting the plane of rotation of the propeller (and hence the total aerodynamic force of the propeller) in the desired direction, to the right or left. In this case, a lateral component of the total aerodynamic force appears, which provides the possibility of lateral movement of the helicopter. In addition, the propeller thrust no longer passes through the center of gravity of the helicopter. Therefore, a moment appears relative to it, rolling the helicopter in the right direction. All this is also the prerogative of the swashplate.

Well, the fourth type of helicopter control - longitudinal control. This is the pitch control of a helicopter, with the helicopter flying forward or backward at the appropriate speed. It is carried out by tilting the plane of rotation of the main rotor and, accordingly, the vector of the total aerodynamic force in the longitudinal direction, forward or backward. In this case, a pitch angle is created (the helicopter lowers or raises its nose) due to the creation of a moment of an inclined aerodynamic force relative to the center of gravity of the helicopter. Plus, a horizontal component of this force appears, which, in fact, moves the helicopter in the right direction. The main role here again is played by the swashplate, which changes the cyclic pitch of the propeller.

So the helicopter has three main units that determine its movement. Engine, swashplate and tail rotor. And, in fact, the control of a helicopter means the control of these three units. There are three systems for this: the swashplate control system (main rotor cyclic pitch control), the tail rotor control system, and the collective pitch control system in cooperation with the engine speed (power) control, or the pitch-throttle system.

What is "step-gas". The fact is that the angle of installation of the rotor blades (common pitch) and engine speed are related. After all, if you increase the angle, then the magnitude of the aerodynamic forces acting on the blades will increase. Both the lifting force and the drag force increase. The screw is said to be loaded. The engine, being at a certain power level, cannot “serve” the increased load and may begin to lose speed. The thrust of the screw, respectively, may decrease.

To prevent this from happening, a step-gas system was invented, which, simultaneously with an increase in the angle of installation of the blades, sends a command to the fuel automation to increase the speed (that is, “increase the step - give gas” and vice versa), thereby excluding a drop in engine power.

Now about what we have in the cockpit. The pilot has actually two helicopter control sticks.

First - cyclic pitch control knob(or just a helicopter control stick). It is of an aircraft type, located in front of the pilot's seat, and with its help longitudinal and transverse control of the helicopter is carried out. From it, through a special system of rods and rockers, the impact is transmitted to the swash plate, which, in turn, determines the cyclic angle of the blades.

Control systems for cyclic and common pitch of the propeller.

Helicopter cabin. The paired control knobs and step-gas knobs are clearly visible.

Second - collective pitch control knob or, as it is also called "step-gas handle". This handle is usually located to the left of the pilot's seat and moves vertically up and down. With its help, vertical control is carried out by simultaneously acting on the swashplate and the engine speed change system. Typically, engine speed changes in the first third of the handle movement, then only the overall pitch of the propeller changes.

Separate from the pitch of the propeller, the power of the engine can only be changed within small limits for the necessary adjustment. For this, there is a special corrector on the step-gas handle (usually something like a rotary ring).

On the diagram under the numbers: 1 - cyclic step control knob; 2 - handle step-gas; 3 - swash plate; 4 - unit of the engine control system.

In addition to the control knobs, there are also pedals. With their help, again, through the helicopter control system, the pilot acts on the tail rotor in order to change the total pitch of its blades, thereby changing its thrust and, accordingly, the turning moment of the helicopter.

Tail rotor pitch control system.

Helicopter cabin. The control knob and the right pedal are clearly visible.

When using all the described organs helicopter control, this device turns into a maneuverable machine with fairly broad capabilities.

The main modes of helicopter flight are takeoff, hover, acceleration and climb, maneuvering and further descent and landing. The usual, however, modes for any aircraft, except, of course, hovering. This mode is still available only to aircraft with vertical takeoff and landing (VTOL), not counting, of course, any exotic :-).

A little more about takeoff mode. There are two ways to take off. The first is "by helicopter". In this case, the helicopter takes off vertically with a short hover at a height of 1.5-2 meters (control hover), after which it accelerates with a climb. The second - "on the plane." At the same time, the helicopter accelerates on the ground, picks up takeoff speed and takes off with a subsequent climb and speed.

The take-off method is selected depending on the state of the apparatus itself and on external conditions. The determining factor in this regard is the engine power reserve, which is quite understandable :-). This margin, in turn, depends on the mass of the helicopter (more precisely, the take-off mass) and on such parameters of the state of the atmosphere that affect the operation of the engine and main rotor, such as local air pressure, temperature and humidity (affecting air density).

Helicopter takeoff.

In addition, the choice of take-off method is influenced by the size and condition of the surface of the site on which the helicopter is located, the presence of any obstacles along the take-off course, and the direction and strength of the wind near the ground.

The higher the barometric altitude of the take-off site (lower pressure), the higher the temperature and humidity of the air, and the lower the headwind speed, the lower the engine power reserve, and the lower the take-off weight of the helicopter should be.

Helicopter takeoff- This is the main type of take-off for modern devices. However, it can also have a different configuration. The fact is that when the propeller is operating near the ground, air cushion effect. This phenomenon, I think, is known to almost every modern person.

The air thrown down by the main rotor is decelerated near the ground and forms, as it were, a pillow supporting the apparatus. This can usually occur at a very small distance from the earth's surface. It is believed that for a helicopter this phenomenon can be taken into account if the distance from the ground to the plane of rotation of the propeller is equal to the radius of the propeller (or less). In this case, the increase in lift is 10-15%.

So takeoff by helicopter can be carried out with acceleration outside the air cushion area or in its area, and acceleration along an inclined trajectory can also be carried out.

The first case is chosen when the take-off area is limited and surrounded by high obstacles, and also if it is heavily dusted or covered with fresh snow. The operating mode of the engine during such a takeoff is the maximum, that is, there is no power reserve.

This is the most stressful take-off mode, and if the engine (one of the engines) fails, a safe landing is not guaranteed. Vertical ascent must be carried out to a height of passage over obstacles with an excess of at least 5 meters.

Takeoff outside the air cushion area from a platform limited by obstacles.

Acceleration on an inclined path can be used on the same site, but with an obstacle height of up to 5 meters. The power reserve during such a takeoff should provide simultaneous acceleration with climb. A safe landing must be guaranteed in the event of an engine failure (one of the engines).

Takeoff with acceleration in the air cushion zone- the most common way to take off. It is usually produced from airfields (heliports) with open approaches. In this case, the engine usually operates at nominal mode, that is, there is a power reserve for the necessary, in which case :-), maneuvering. The helicopter after the control hover accelerates along the ground with a pitch angle for a dive of 10-15 º (sometimes more, and this is very effective :-)) and then goes into climb. This take-off, by the way, is the most common of what we see in the movies.

If it is impossible to take off by helicopter, then the helicopter can take off by plane, taxiing to the launch site for this. Further, everything is like an airplane :-). The step-throttle stick is set to the takeoff mode, the control stick is given a little away from you (for the appearance of horizontal thrust), the helicopter takes off and, having gained a certain speed (about 40-50 km / h), after taking the control stick a little, it takes off from the ground . Then some holding at a height of about 1.5 meters and lifting.

Airplane takeoff.

So in short about the possibilities of takeoff. We will talk about other working (as well as emergency and special) flight modes in the following articles and according to the wishes of the workers :-).

In the meantime, I think it is clear to everyone that in any flight modes the control is carried out by joint movements of the helicopter control sticks, step-gas and pedals. Helicopter control as close as possible to the aircraft, but the differences, of course, are obvious. Helicopter pilots even learn how to observe the ground from the cockpit in a different way. There's nothing you can do, specificity. Yes, and comparing a helicopter and an airplane would probably be wrong. However, as they say, both please the eye :-). Both fly amazingly well. What else is needed? 🙂 :-)…….

At the end of the article I put a video that is already in my article about. For today's article, it fits perfectly :-). Takeoff with acceleration in the air cushion zone. The truth is not quite typical, but with the use of another element called chic, bordering on air hooliganism. However, it looks impressive! :-). Pilot... Hats off...

To top it off, there is a video “About how a helicopter flies”. The latter, unfortunately, is in English. But some useful points from the point of view of management in it can be understood and they are well shown. Unfortunately, this time I did not find a more acceptable material 🙁 ...

Until we meet again…

Photos are clickable.

Mi-2 (according to NATO classification Hoplite) is a Soviet multi-purpose helicopter developed by OKB M. L. Mil in the early 1960s. It is widely used to perform many civil and military tasks. In 1965, mass production was launched in Poland. Over 5400 units built. Even now, the Mi-2 takes part in tenders, competing with its successors Ka-226 and Ansat.

In the late 1950s, a small, light Mi-1 helicopter became widespread in the Armed Forces and the national economy of the USSR. It was equipped with an AI-26V piston engine, which no longer met the requirements of that period. There were projects to improve the Mi-1 helicopter (including those with one gas turbine engine), but they did not receive approval. The idea was born to use a power plant on a new helicopter, which would consist of two gas turbine engines. This would greatly increase the reliability and safety during the flight. This project later became known as B-2.

Initially, the leaders of the Civil Air Fleet showed the greatest initiative in working on the B-2, but later the military became interested in creating a new light helicopter. As a result, on May 30, 1960, the Mil design bureau was entrusted with the creation of a helicopter in agricultural, passenger, transport, sanitary and training modifications. When creating and fine-tuning the V-2, the Mil Design Bureau used Mi-1 parts and assemblies as much as possible, in particular the main rotor, main gearbox assemblies, and transmission.

The GTD-350 engine with a capacity of 400 hp was created. With. According to its characteristics, the GTD-350 was much inferior to foreign engines, but its creation made it possible for the Mil Design Bureau to design a new second-generation light helicopter, equal in size to the Mi-1, but having a larger passenger capacity (8 people instead of 3) and more superior to its flight performance parameters.

A gas turbine engine (GTE) is a heat engine in which the gas is compressed and heated, and then the energy of the compressed and heated gas is converted into mechanical work on the gas turbine shaft.

Unlike a piston engine, processes in a gas turbine engine take place in a flow of moving gas.

Compressed atmospheric air from the compressor enters the combustion chamber, fuel is also supplied there, which, when burned, forms a large amount of combustion products under high pressure. Then, in the gas turbine, the energy of the gaseous products of combustion is converted into mechanical work due to the rotation of the gas blades by the jet, part of which is spent on compressing the air in the compressor. The rest of the work is transferred to the driven unit. The work consumed by this unit is the useful work of the gas turbine engine. Gas turbine engines have the highest specific power among internal combustion engines, up to 6 kW/kg.

Any fuel that can be dispersed can be used as a fuel: gasoline, kerosene, diesel fuel, heating oil, natural gas, marine fuel, water gas, alcohol and crushed coal.

In 1965, the Mi-2 began to be exported. Basically, these helicopters were delivered to the USSR and other countries of the socialist community. In addition to the Soviet Union, the Mi-2 was purchased by Burma, Bulgaria, Hungary, East Germany, Egypt, Iraq, North Korea, Cuba, Lesotho, Libya, Nicaragua, Romania, Syria, Czechoslovakia and Yugoslavia. In 1978, one Mi-2 in an agricultural version even ended up in the USA, receiving registration number N51946.

Later, thanks to the re-export, the Mi-2 appeared in other states, such as Djibouti, Turkey, Venezuela, etc.

The design of the Mi-2 helicopter consists of:

1. Fuselage

2. Power plant

3. Fuel system

4. Carrier system

5. Crew cabins

7. Flight equipment

8.Optional equipment

10. Electrical equipment

The fuselage of the Mi-2 has a semi-monocoque design, it includes three parts: the nose part, where the cockpit is located, the central part with the passenger compartment and the tail part, it includes a tail boom with a controlled stabilizer.

Power point

Mi-2 has an all-metal construction. The power plant is located in a large superstructure above the fuselage of the helicopter - the so-called "boar" (from the French cabane - a hut). In front of the three-stage main gearbox there are two GTD-350 engines, and on top there is a fan, a cooling oil cooler and the main gearbox.

Fuel system

The fuel system of the helicopter includes one fuel tank with a capacity of 600 liters, located under the cabin floor, it is also planned to install two additional tanks on the sides of the fuselage, with a capacity of 238 liters. The oil system includes an oil block with a capacity of 25 liters and an oil cooler with a fan for cooling.

Carrier system

The carrier system includes a three-blade main rotor with rectangular blades and a two-blade tail rotor. Hydraulic dampers are installed on the main rotor. The control of the general and cyclic pitch of the main rotor is carried out using hydraulic boosters. In case of failure of the hydraulic system, the pilot can apply manual control.

crew cabin

The cockpit is single-double, most often, the pilot sits on the seat on the left, in the training modification, the pilot and cadet sit side by side, in which case the control of the helicopter is doubled.

The pilot and passenger seats are located in front of the fuselage, batteries and various equipment were also located there. Behind is a cargo-passenger cabin with a door on the port side. It measures 2.27 x 1.2 x 1.4 m and is equipped with an air conditioning system. A fuel tank container is attached to the cabin floor, which simultaneously serves as an attachment point for two three-seater sofas. For one more (eighth) passenger, a folding seat is attached to the rear wall of the case. When transporting goods, the passenger seats can be removed. In the sanitary model, up to four stretchers can be installed in the cabin, and there is also a place for an accompanying paramedic.

Flight equipment

The flight equipment on the Mi-2 helicopter is standard and includes a radio compass, gyrocompass, radio altimeter, MW and HF radio stations. For military options, a radar receiver is mounted in the bow.

Optional equipment

Two additional cylindrical fuel tanks can be installed on both sides of the fuselage. The helicopter is equipped with a cargo winch and an external suspension system with a payload capacity of up to 800 kg. On the tail boom is a controlled stabilizer; its angle of rotation will automatically change in accordance with the change in the pitch of the main rotor blades.

The agricultural variant has a system for spraying liquid chemicals, it includes: tanks on the sides of the body, with a total capacity of 1000 liters and a sprayer boom 14 m long, with 128 nozzles, which provide spraying chemicals over an area 40-45 m wide, or spraying dry chemicals with a total weighing 750 kg, which are contained in two containers with sprayers.

The search and rescue modification has an electric winch with a carrying capacity of 120 kg, and the transport version has a hook for external suspension of loads weighing up to 800 kg. The variant intended for environmental monitoring has ASA thermal imaging equipment.

The tricycle landing gear consists of two pyramidal main legs and a two-wheel front leg with link suspension. Single-chamber, pneumatic-oil shock absorbers are installed on the landing gear racks. In winter, a ski or wheel-ski chassis can be installed. The chassis allows the helicopter to taxi, as well as take off and land like an airplane.

electrical equipment

DC sources: two accumulators of 24 V, and two STG-3 starter-generators of 3 kW, 27 V. AC sources: generator 16 kW, 208 V, 400 Hz, powered by the main gearbox. AC networks 36 V and 115 V in normal mode are powered by converters that are powered from the DC network. In emergency mode - from the alternator through the transformer. The most powerful consumer - anti-icing system - is powered by an alternator.

Armament

Military versions intended for combat operations can be equipped with the NS-23 cannon and 6 machine guns, the NS-23 cannon and 2x16 NAR S-5, the NS-23 cannon, 2 machine guns and 4 Malyutka anti-tank guided missiles, the NS-23 cannon , 2 machine guns and 4 Strela-2M homing anti-aircraft missiles.

Mi-2 in comparison with other multi-purpose helicopters.

SCHEMES Mi-2

The layout of the helicopter Mi-

1. heated glass

2. Oil tank

3. Gas turbine engine GTD - 350

4. Starter - STG-3 generator

6. Fan installation

7. Main gearbox

8. Rotor hub

9. Swashplate

11. Alternator

12. Fire fighting cylinders

13. Tail shaft transmission

14. Antenna

16. Transmission tail shaft cover

17. Intermediate gearbox

18. Tail screw

19. Tail gearbox

20. Light beacon

21. End beam

22. Tail support

23. Trim weight (for dual control helicopters)

24. Stabilizer

25. Door to the radio compartment

26. Shock absorber of the main legs of the chassis

27. Chassis main leg frame

28. Main fuel tank

29. Sofa passengers

30. Pilot's seat

31. Air pressure receiver

32. Battery compartment

Flight performance of the Mi-2T

Engines 2 x GTD-350

Power, kW (hp): take-off 2 x 294 (2 x 400)

nominal (no more than 1 h) 2x233

Power consumption for tail rotor drive, % 8.57

The total length of the helicopter (with rotating propellers), m 17,420

Fuselage length, m 11,940

Helicopter height (to the main rotor hub, without tail rotor), >> 3 ,750

Rotor diameter, m 14.560

Tail rotor diameter, m 2,700

Chassis track, m 3,050

without dual control 2402

twin control 2445

sanitary version without double control 2410

sanitary version with double controls 2420

cargo modification 2372

Maximum load capacity, kg:

cabins 700

external suspension 800

winch crane LPG-4 120

Flight weight, kg:

normal 3550

maximum 3700

Main fuel tank capacity, l 600

The total capacity of two external fuel tanks, l 476

The total capacity of the fuel system with two PTB, l 1076

Speed, km/h:

Max. permissible (instrumental) at an altitude of 500 m with a takeoff weight of 3550 kg 210

Max. permissible (instrumental) at an altitude of 500 m with a takeoff weight of 3700 kg 190

cruising (instrument) at an altitude of 0 to 1000 m with a takeoff weight of 3550 kg 190

cruising (instrument) at an altitude of 0 to 1000 m with a takeoff weight of 3700 kg 170

cruising at an altitude of 50-1000 m (at a temperature of 25 ° C and above) 180

Maximum flight speed back and sideways, km/h 10

Maximum turning speed when hovering, deg/sec 20

Vertical speed near the ground, m/s 4.5

Maximum flight altitude (dynamic ceiling), m:

at takeoff weight 3550 kg 4000

at takeoff weight>> kg 3500

Hovering ceiling, m 1500

Practical flight range at an altitude of 500 m with a maximum target load and 5% ANZ, km:

without PTB 170

with two PTB 580

Flight range at an altitude of 500 m with 830 kg of fuel and a reserve of 100 l, km:

at takeoff weight 3550 kg 516

at takeoff weight>> 3700 kg 514

Flight range at an altitude of 500 m with 465 kg of fuel and a reserve of 100 l, km:

at takeoff weight 3550 kg 262

at takeoff weight 3700 kg 257

Weight of transported cargo, kg:

at a distance of 200 km 690

at a distance of 400 km 392

Productivity, t-km/h:

at a distance of 200 km 102

at a distance of 400 km 63

Fuel consumption, kg / t-km:

at a distance of 200 km 1.81

at a distance of 400 km 3.12

The mass of the transported cargo at the height of the take-off area of ​​1000 m, kg:

at a distance of 200 km 700

at a distance of 400 km 432

Performance at a runway height of 1000 m, t-km/h:

at a distance of 200 km 102

at a distance of 400 km 68

Fuel consumption at a runway height of 1000 m, kg / t-km:

at a distance of 200 km 1.71

at a distance of 400 km 2.72

The design of the Mi-2 helicopter

The helicopter is built according to a single-rotor scheme with a tail rotor, two gas turbine engines and a tricycle landing gear.

The semi-monocoque fuselage consists of three parts: a nose with a central one with a passenger cabin and a tail boom with a controlled stabilizer with a span of 1.85 m and an area of ​​0.7 m2, the installation angle of which changes synchronously with the change in the common pitch of the main rotor blades. The cockpit is located in the forward part of the fuselage. crew with two seats (in most options, one pilot is on the seat on the left, on the right seat is a passenger; in the training version with dual control, the instructor pilot and cadet are placed

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to the cockpit through two doors (left - sliding, right - hinged); early series helicopters had a sliding window for emergency escape instead of the left door.

The central part of the fuselage is a cargo-passenger cabin measuring 2.27 x 1.2 x 1.4 m, in the middle part of which there is a fuel tank container. In the passenger version, the container serves as the basis for the installation of two triple seats, facing each other with their backs (forward and backward); in the rear of the cabin there is a folding seat for the eighth passenger. The cab is equipped with an air conditioning system. When transporting goods, the passenger seats can be removed. In the sanitary variant, the cockpit has mounts to accommodate four patients on a stretcher with an orderly or two on a stretcher and two on the seats. Access to the cargo-passenger cabin is carried out through a hinged door measuring 1.1X0.78 m from the left side.

Chassis tricycle, non-retractable. The main supports are pyramidal, with oil-air shock absorbers and brake wheels KT-96 / 2 with dimensions of 600 (180 mm; self-orienting nose support, with twin wheels Kz-50 with dimensions of 300 (125 mm). The pressure in the pneumatics of the main supports is 0.43 MPa ( 4.4 kgf / cm2), nose support - 0.34 MPa (3.45 kgf / cm2). It is possible to install metal skis with cutouts for wheels or without them.

The power plant consists of two GTD-350 turboshaft engines with a take-off power of 298 kW / 400 hp, developed under the direction of S. P. Izotov and produced under license in Poland. Engines with protruding air intakes and bifurcated exhaust pipes are mounted side by side in a common fairing; between them there is a fan with a frontal air intake for cooling the oil cooler of the engines and the gearbox.

The transmission consists of a three-stage main gearbox VR-2 with a freewheel, an intermediate gearbox, a tail rotor gearbox and connecting shafts. The main gearbox has a gear ratio to the main rotor shaft of 1:24.6 (0.406), the tail rotor gearbox is 1:4.16 (0.24). The torque of the free turbines is transmitted to the input shafts of the freewheels of the main gearbox through the gearboxes installed on each engine with a gear ratio of 0.246. The helicopter is equipped with a system for maintaining a given main rotor speed.

The main rotor is three-bladed. The blades are connected

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the horizontal hinges of the bushing are spaced apart and rotated, the vertical hinges are equipped with hydraulic dampers; a swing compensator with a coefficient k = 0.4 was introduced into the design of the sleeve.

Main rotor blades with NACA 230-12M profile and 0.4 m chord are rectangular in plan and have a geometric twist of -6°. The blades are all-metal, with a pressed spar and a honeycomb filler in the tail sections. There are 40 mm wide trim tabs on two compartments of each blade. The blades are equipped with pneumatic signaling of damage to the spar.

The tail rotor with a diameter of 2.7 m is a two-bladed, pusher, variable pitch in flight, two-bladed, with all-metal rectangular blades in plan. For the first time in the practice of domestic helicopter construction, torsion bars were used in the tail rotor hub.

The booster control system, with hydraulic boosters in the channels of longitudinal and transverse control and common pitch control and spring loading mechanisms, is driven by a hydraulic system with a working pressure of 6.5 MPa (66 kgf / cm2) and a capacity of 7.5 l / min.

The fuel system includes one fuel tank with a capacity of 600 liters under the cabin floor, it is possible to install two additional tanks on the sides of the fuselage with a capacity of 238 liters each; The oil system consists of an oil tank with a capacity of 25 liters and an oil cooler with a fan for cooling.

The hydraulic system is not duplicated, since even in the event of a hydraulic failure on a helicopter, all evolutions can be performed, while the efforts on the pilot's controls have acceptable values.

The AC electrical system is powered by two STG-3 starter-generators with a power of 3 kW, driven by engines, and a generator

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powered by two lead-acid batteries with a capacity of 26 A. h.

The pneumatic system with a working pressure of 4.9 MPa (50 kgf/cm2) provides the brake drive of the main wheels.

Anti-icing system (SIS): The rotor blades of the main and tail rotors of the helicopter, as well as the left windshield of the cockpit are equipped with an electrothermal SIS.

Pilot-navigation and radio communication equipment, which allows flying day and night in simple and difficult weather conditions, includes CB and KB radio stations, a gyrocompass, a radio compass, a radio altimeter and an aircraft intercom (SPU). On a number of military options in the bow and on the tail boom there are receivers for the radar warning system (SPO).

Special equipment: The helicopter has an external suspension designed to transport cargo outside the cargo compartment. The load capacity of the external suspension is 800 kg. To perform rescue operations, the helicopter is equipped with a cargo boom and an electric winch, with the help of which, in the hover mode, people and loads weighing up to 150 kg can be lifted on board the helicopter.

In addition to the basic (transport) version, the Mi-2 helicopter can be used in several other versions. In the passenger version, it can accommodate 8 passengers. In the sanitary variant, the helicopter is equipped with four stretchers for transporting bedridden patients, accompanied by one medical worker. The helicopter from the transport version to the ambulance can be easily converted in the field.

In the agricultural version, special equipment is installed on the helicopter, which makes it possible to spray or pollinate fields, gardens and forests with various chemicals. Chemicals are placed in two tanks located

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heh chemicals. Spraying of chemicals is carried out with the help of special fans (in the version for pollination) and pumps (in the version for spraying) located in the lower part of the tanks and driven by electric motors located there. In the spraying version, the helicopter is equipped with 14 m long sprayer booms with 128 nozzles that spray chemicals in a 40–45 m wide swath.

The search and rescue version is equipped with an electric winch with a carrying capacity of 120 kg, and the transport version is equipped with a hook for external suspension of loads weighing up to 800 kg. On the variant for environmental control, thermal imaging equipment of the ASA company is installed.

Armament: In the Mi-2URN fire support variant, pylons for two MARS blocks of 16 NAR S-5 caliber 57 mm are installed on the sides of the fuselage, and in the Mi-2URP anti-tank version, 4 9M14M Malyutka or 9M32 Strela-2 ATGMs are suspended on pylons ". The Mi-2US variant for fire support is armed with a 23 mm NS-23KM cannon mounted on the left side of the fuselage, and two MARS units or 6 7.62 mm machine guns (two on pylons on the sides of the fuselage and two in the cockpit).

Characteristics of the main modifications of the Mi-2

* Data refer to helicopters from factory No. 1623 (i.e. 511623100) according to the factory No. 3350 (i.e. 543350024).