As a result the fruitful activity of domestic helicopter-building, the Soviet Union to the middle the 70's became the possessor of the largest in the world fleet of the helicopters, which intensively were exploited in the military and civil aviation subdivisions. However, in contrast to the majority of the Western countries, where predominated small-engine aviation, major portion of the domestic helicopter park they composed the machines of average and heavy classes. This was in many respects determined by the special features of the operation of rotary-wing apparatuses in our country, and also by the low priority of light machines under the conditions of the planned economy. The aircraft designers of participating countries COMECON (Council for Mutual Economic Assistance) successfully managed the development of light aircraft, but to independently create a similar helicopter it proved to be not under the force, since its development, building and finishing were connected with the need for the solution of the most complex specific problems. The design of small-engine helicopter it could carry out only this experimental qualified design association as " [MVZ] [im]. OF [M].[L]. mile ".
An attempt at the creation at the end of the 60th - beginning the 70's of helicopter for the change to veteran Mi-1 was not crowned with success because of the absence of the suitable domestic gas turbine engine. At the same time in the second-half the 70's in the training subdivisions VVS and the aero clubs of DOSAAF (All-Union Voluntary Society for Assistance to the Army, Air Force, and Navy) began the mass writing off of training Mi-1, that manufactured its resource. The replacement of them considerably heavier and more expensive Mi-2 proved to be economically unfavorable. [Krome] [ty], [Mi]-2 did not give to our athletes of advantages with the fulfillment of aerobatics. In connection with this the leader of DOSAAF the Air Marshall Of [a].[I].[Pokryshkin] personally turned himself in 1979. to the chief designer [M].[N].[Tishchenko], who in the youth was also fascinated by aviation sport, with the request to examine the possibility of the renewal of works on the light helicopter.
Colleagues " [MVZ] of [im].[M].[L].[Milya] " with the readiness supported the rotation of the outstanding pilot. In 1980. in OKB began the design of light training- sport helicopter Mi-34 (article 300). It did not need the development of gas turbine engine, since the aero clubs of DOSAAF many years successfully exploited the flight vehicles (including Su-26 and Yak-50), equipped with the piston engines M-14, which possessed high reliability, sufficient power, high fuel effectiveness and pick-up. This helicopter, piloted by one sportsman pilot, with the small fuel stock had to carry out pilotage with the three G-forces, revolve relative to vertical axis with a angular velocity of more than 60 degrees per second and fly "by tail forward" with a speed not of less than 130 km/h. After the installation of second armchair and second complete set of control elements the helicopter was converted into the training. Mi-34 with the complete content of equipment, the normal fuel stock and the commercial load it could be used as the multipurpose machine, in this case besides pilot the helicopter could raise two-three additional passengers.
The management of branch supported project Mi-34, and at the end December 1980. the order of the minister of aircraft industry about the preparation for technical proposal on the light training- sport helicopter appeared. In the first half of the following year it was sent out into the Research Institutes [MAP]. Together with TsAGI (Central Institute of Aerohydrodynamics im. N Ye Zhukovskiy) the specialists [MVZ] conducted on the stand the preliminary analyses of stability, controllability and maneuverability, and also they approached model test in the wind tunnel. The agreement of technical task on Mi-34 somewhat was tightened, since it was necessary to convince servicemen of the expediency of applying the piston engine. In connection with this summer 1981 g. in OKB in parallel with the development of basic design began the study of modification Mi-34[M] with the promising gas turbine engine. However, the periods of the creation of this engine were indeterminate, and DOSAAF urgently it needed training- sport machine. Therefore in 1982. command VVS made the decision to support project Mi-34, considering it as reserve for the following promising light multipurpose helicopters. " [Milevtsy] " approached draft designing.
[M].[N].[Tishchenko], personally led the development of new helicopter, appointed chief designers Mi-34 of experienced engineers [N].[A].[Nazarova] and [A].[V].[Fedotova]. For the assertion of technical task, draft designing and modeling of aggregates and helicopter as a whole left more than a year. At that time on [MVZ] priority were considered building and flight tests of combat Mi-28, and also modifications Mi-8 and Mi-24, that correspond "Afghan" requirements; therefore to works on Mi-34 was given marginal importance, that somewhat tightened design and tests of helicopter. Furthermore, the creation of small machine required from the designers of the solution of number of the most complex technical problems, which include the layout of cab, the arrangement of engine, the design of the hinge-free bushings of carrier and tail rotor, glass-plastic blades, skid landing gear and so forth.
With the design of the helicopter of light class the great significance has dimensional factor. Some elements of construction, such as the armchair of pilot, control levers, instrumentation cannot have sizes of less than determined. The same concerns the thickness of skin. The nonobservance of the culture of weight design in the small machines entails considerably more severe consequences than on the helicopters of the middle class: load capacity can prove to be insufficient, load ratio - low, and entire helicopter - by economically unfavorable. The problem of the development of helicopter with high for their time technical and economic indices was aggravated even and by the need for use on Mi-34 of piston engine, by no means lung itself and compact in its category.
In order to personify into the life the design of highly effective light helicopter for colleagues " [MVZ] [im]. OF [M].[L]. mile " it was necessary to use entire accumulated by them experience of design and finishing of rotary-wing apparatuses. Prolonged bench tests preceded the building of machine. In all were created about 45 stands, including full-scale stand and stands of repeated-static and fatigue tests.
The development of small machine was activated in 1984 ; after on February 10 the commission of the presidium of the Council of Ministers of USSR made a decision about the creation of light training- sport helicopter Mi-34. At the end October state commission affirmed the final mock-up of helicopter. In parallel it was completed and its is working design. In 1985. experimental production [MVZ] finished the production of full-scale model for the static tests of fuselage, and also resource copy, which entered immediately the [vibrochastotnye] and ground tests. In the process of assembling plant specialists worked out new technological processes and rigging for preparing of glass-plastic blades, skid landing gear, cockpit windows, torsion bushing, elements of transmission and control.
In June 1986. was assembled the first flying copy Mi-34, which was the light training- sport helicopter, intended for the execution of training flights by the cadets of training centers and aero clubs, and also training flights and acrobatic maneuvers by sportsman pilots. Machine was calculated for the triple flight overload and built according to classical single-rotor design with four-blade carrying and two-bladed with tail rotors. The special feature of layout Mi-34 was the nontraditional arrangement of engine - its axis was not stale in the longitudinal plane of the symmetry of fuselage, thanks to which the center of gravity of motor and its vertical power take-off proved to be sufficiently closely to the axis of rotor, but engine itself, in spite of his overall sizes, successfully it was entered in the circumscriptions of fuselage.
Fuselage Mi-34 - the all-metal semi-monocoque of variable section, prepared from the aluminum alloys, included lamp, center section with the tail boom, keel, stabilizer and upper cowling- fairing. Cockpit glass of large area ensured a good view from the cabin. In the lamp they were placed: flight deck with two entrance doors, control elements of helicopter, flight equipment, storage battery and compressed air tank. Center fuselage consisted of cargo-passenger cab with two side doors, engine compartment and equipment bay. In the cab, situated between two basic load-bearing elements (third and fifth frames), detachable two-place seat was located. On top the longitudinal pressed beams with the units for fastening of the main rotor gearbox were passed between the frames. All four doors of helicopter were equipped with the mechanisms of emergency discharge. From behind to the fifth frame with the aid of the struts engine was fastened. Tail boom was semimonocoque cone-shaped construction. Keel and stabilizer located on it had riveted monospar construction.
The opened folds of engine compartment, inspection holes and removable covers ensured operational approaches to the engine and other systems. In the construction of aggregates and systems were used riveted and glue-welded panels, cast and stamped parts from the aluminum alloys, glass-plastic skins so forth in the limited quantity were used steel and titanium alloys.
Flight deck was equipped with the dual set of control levers, the left levers and the pedals could easily be dismantled. In the piloting version for decreasing the takeoff mass they were removed together with the left armchair and the equipment component. Control system Mi-34 did not have hydraulic amplifiers. The installation of longitudinal-transverse control was equipped with the screw mechanisms of unloading. Cab was equipped with instrument panel, central control panel and with device of heating with the heat supply to the glass and to the feet of pilots. The flight, radio-technical and instrumentation established on the helicopter provided piloting and solution of the problems of navigation in the training and sport flights in the daytime under clear weather conditions. The blades of rotor were prepared from the composite materials, and their basic load-bearing element - longeron was carried out by the method of the spiral coil of unidirectional fiberglass tapes. The solid tail section of the blade consisted of [organotekstolitovoy] skin and filler. Rotor hub had the locked lamellar torsion shafts made of high-strength steel, which receive thrusts centrifugal force of opposite blades and ensuring flapping in the plane. The tail rotor with a diameter of 1,48 m consisted of the torsion being rocked bushing with the general slanting flapping hinge and glass-plastic blades with the longerons, which pass into the housing of feathering hinge.
On Mi-34 is established piston nine-cylinder four-stroke air-cooled engine M-14[v]26[v] with a power of 325 hp with the centrifugal blower and the built-in reducer, by the combination sleeve of start, and also by fan for cooling of cylinders and oil. The starting of motor was achieved from the pneumatic system. Transmission consisted of main and tailed reducers, connecting shaft and tailed shaft. The main rotor gearbox - with the cylindrical transfer, without the external lubrication system. Fuel system included two those located under the sex of the cargo-passenger cab the collapsible propellant tanks with a capacity of 177 l, pumps, and also ensuring reliable fuel feed during the performance of the acrobatic maneuvers of the camera of negative overloads and other systems. Chassis of helicopter - skid type with the protective support on the keel.
The first flying copy Mi-34 entered the flying station " [MVZ] [im]. OF [M].[L]. mile " in September 1986 ;, also, after preliminary ground-based finishing works the test pilot Of [b].[V].[Savinov] on November 17, 1986. carried out on it the first hovering. After the first successful lifts and bench tests the design project leader [M].[N].[Tishchenko] permission to the first departure, which took place on December 26 the same year. The results of preliminary tests were encouraging, and after only four days took place the official transfer of the light machine for the stage "A" of joint official tests. Simultaneously began the transfer of working design documentation for the series production at the Transcarpathian Machine Building Plant. The possibility of the building of helicopter on the license in the friendly countries was examined. In 1987. the flight tests entered the second flying model Mi-34, and resource copy successfully was advanced at the airshow of Le- Le Bourget, where it proved that the firm [M].[L]. mile was capable of building not only heavy technology. Not less effectively presented Mi-34 domestic light helicopter construction, also, on the American exhibition in San Diego in 1988. In August 1988. test pilot [B].[V].[Savinov] in the history of domestic helicopter construction for the first time performed in the helicopter of acrobatic maneuver - "Nesterov's loop" and "barrel", whiched indicate salient qualities of [milevskoy] machine and its correspondence to the stringent requirements of customer. In all in the stage "A" of flight tests on three helicopters were executed about 280 flights with the general attack 123 h.
As usual, all stages, beginning from the bench tests, were accompanied by the elimination of the revealed deficiencies and defects, by the finishing of aggregates and systems of helicopter. The foam plastic filler of the tail section of the blades of rotor to the honeycomb was substituted according to the results of bench tests and ground-based races of resource model; changes in the construction of oil tank are introduced; the components of transmission are intensified; are [usovershenstvovany] the exhaust ducts of engine. During conducting of stage "A" of tests were finished air duct for cooling of engine and cover with the outlets for a decrease temperatures of cylinder heads; is increased the length of the power take-off of tailed reducer for changing the natural frequencies of the system, which made it possible to decrease the stresses in the shaft; are established resin-metal dampers on the rotor hub; the thickness of skin of tail boom is increased; the site of installation of the tail assembly is changed; are [usovershenstvovany] the units of the system of control and power plant; the conditions of the work of pilot are improved.
In December 1988. [MVZ] sent Mi-34 to the stage "B" of joint testing in [GNIKI] VVS. On the observations of commission for the inspection of helicopter at the plant the deficiencies were liquidated and additional flights were executed. In the latter of them on February 27, 1989. occurred the catastrophe, in which perished the test pilot [B].[V].[Savinov]. Flight was passed in the rainy weather, under the conditions of strong turbulence and sharp gusty wind. Commission from the specialists of TsAGI, Leah and [MVZ] after conducting in 1989-1991 yr. of theoretical and experimental studies of the dynamics of screw and system of control in the conditions, similar to those arisen in flight, recommended the introducing of design changes. Into the construction of bushing hydraulic and resin-metal dampers were introduced. System of control and chassis were simultaneously finished. The resource copy Mi-34 they converted into the flying, on which were carried out successful monitoring tests. Further plant tests Mi-34, including landings under the conditions of autorotation, conducted test pilot [S].[S].[Barkov].
All this in conjunction with the increasing in the country economic crisis tightened finishing Mi-34. The disintegration of the Soviet Union entailed stoppage was already the fixed in the Transcarpathian region series production of helicopters. The main customer of the helicopter of DOSAAF ended his existence. As a result Mi-34 it returned for the stage "B" official tests only at the end by 1992 g.
Official tests of helicopter were conducted in 1993-1996 yr. in the state flight-test center (former [GNIKI]) of VVS, in parallel the modification of construction was continued with them. On Mi-34 were established "being broken" knob of the cyclic control and steps for facilitating abandoning helicopter in flight, was reduced admittance for balancing of tail rotor for the exception "of itch" in the pedals, was developed the new attachment point of the sleeves of bushing with the blades of rotor, and also tailed reducer with the increased resource.
Large role in the preparation for series production Mi-34 played the establishment on the initiative of leader " [MVZ] [im]. OF [M].[L]. mile " [M].[V].[Vaynberga] of public company "light helicopters "of Mie", into composition of whom they entered: " [MVZ] [im]. mile ", [Arsenevskaya] air carrier "progress", Vyatsky machine-building enterprise "[Avitek]", Ulyanov aggregate plant, [NIAT], By [giproniiaviaprom] and other efforts of enterprises were crowned with success. On November 4, 1993. rose into air the first series Mi-34, built with [arsenevskim] plant.
Similar to all other helicopters of firm [M].[L].[Milya] Mi-34 it served grow prettier by base for creating of new modifications and versions. To order the Moscow police [MVZ] it constructed in 1993. special patrol modification Mi-34[P], equipped with the connected, loud-speaker, illuminating and survey equipment, including the thermal imaging system of firm "It [elbit]" and the gyrostabilized binoculars.
The modification of the helicopter, equipped in accordance with the certification requirements, was called name Mi-34[S]. In May 1995. helicopter was certified on the domestic standards of airworthiness, equivalent FAR (JAR) - 27, which removed all limitations on the operation in Russia and the countries of the CIS, and it also placed the basis of the certification of helicopter for sale into other countries. In all were released 22 helicopters of adjusting party. They entered to [ekspluatantam] into the Russian Federation and for the boundary - into Kazakhstan, Nigeria and Croatia.
Thus, as a result the long-standing labor of scientists, designers, technologists, workers and test pilots " [MVZ] of [im].[M].[L].[Milya] " together with the specialists of other aviation scientific and design organizations is created the base series version of multipurpose helicopter Mi-34, that possesses high technical and economic indices and salient piloting characteristics. The level of the permissible overloads and the effectiveness of control Mi-34 do not have equal among the helicopters of this class. Many pilots evaluate the controllability of helicopter as excellent. For his piloting it is not required special preparation. On Mi-34 is carried out the piloting program, which organically entered into the exponential appearances of best domestic and foreign aviation engineering on the aviation holidays and the international exhibitions. The designed as trainer heliocopter, Mi-34 possesses also all necessary parameters for the multipurpose application, the fulfillment of aerial observation and patrolling, guaranteeing of a connection, ecological monitoring, business- flights, transportation of people and loads and so forth the experience of the creation of patrol modification Mi-34[P] confirmed that the helicopter at will of customer can be equipped with any instruments of the within the framework located load capacity.
After creating Mi-34, domestic [vertoletostroiteli] liquidated their long-standing delay in the area of light technology. Relying on experience of designing, building, flight tests and finishing Mi-34, " [MVZ] of [im].[M].[L].[Milya] " prepares for the implementation of large-scale programs on the production of new light helicopters, hoping because of them not only to overcome today's financial difficulties, but also to begin the advance of its production for the World Market.
Great opportunities of further upgrading and development of the Mi-34 helicopter open owing to the power unit improvement, which main trend is the potential hopping up the M-14V26V motor/engine up to 370 hp given the simultaneous improvement of main rotor efficiency and lower fuselage parasite resistance. Furthermore, Mil designers together with Volga Automobile Plant engineers have developed a Mi-34V?Z modification (military designation - Mi-34M), providing for installation of rotary-piston engines.
The third upcoming trend of improving the powerplant of the Mi-34 helicopter is the replacement of piston engines by gas-turbine ones. Provision for such upgrading of the helicopter was made from the beginning of helicopter development, however from the middle eighties a course was set for designing a heavier Mi-44 helicopter. Mil specialists reverted to the idea of reequipping the Mi-34 with the revolutionary/brand new engine ten years later. Therefore the Moscow Airshow in Zhukovsky in 1995 saw a mock-up of a challenging Mi-34A modification with the foreign turbo-shaft 450 hp engine. Turbo-shaft engines open new improvement feasibilities for technical and economical characteristics of the Mi-34 helicopter together with enlarging the range of application and market area.
For a variety of causes, mainly organizational and economical, production of Mi-34 helicopters was stopped in the late 1990s to the beginning of the 21st century. Nowadays Mil Moscow Helicopter Plant, JSC is resuming work within the frames of the established helicopter holding company on retrofitting and improving the Mi-34C and working on the program of further modifications of the helicopter including the following:
- Mi-34U - with piston engine of increased power;
- Mi-34UT - training helicopter with dual control;
- Mi-34BPV - unmanned multifunction helicopter;
- Mi-34A - with turbo-shaft engine like Arrius (France) or ?I-450 (Ukraine - Russia).
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