Mi-28 HAVOC - History
The concept of combat helicopter is a process of a long way of changes and improvements. One of the corner questions was the production of ideas about the most effective tactics of the application of rotary-wing attack aircraft, the appropriate complex of armament and, therefore, to diagram and to the layout of combat apparatus. In the course of designing "air combat vehicle of infantry" Mi-24 in developers and in customers appeared new ideas relative to the prospects for further development of the helicopters of a similar designation.
In parallel with the concept of the transport- combat helicopter, intended for increasing the mobility of the powered rifle troops and simultaneous guarantee of their fire support, M.L.Mil and its companions-in-arms planned the design of the specialized highly maneuverable rotary-wing "air tank", which would serve "flying platform for the installation of all possible armament". In this version the transportation of landing no longer was provided for. The increased interest in such helicopter was in many respects caused by building in the USA (firm Lockheed) the high-speed and maneuverability combat rotorcraft AH-56 Cheyenne, widely proclaimed by western press. For achievement the high performance characteristics, compared with the characteristics of attack aircraft, AH-56 was equipped with the pushing propeller, wing, rigid hinge-free rotor, and also with elaborate complex of aiming and flight equipment.
Accepted on May 6, 1968, the decision by the CC CPSU and the Council of Ministers of USSR about the creation Mi-24 provided for, in the number of other, and development on its basis of the promising model of the rotary-wing attack aircraft, which possesses higher flight speed, grow prettier by stability and by maneuverability. Toward the end year in the division of promising designing [MVZ] was executed the first project of the rotorcraft Mi-28, which was further development Mi-24 without the landing- cargo cab, but with the rigid rotor, the additional propulsive means and the intensive armament. Unfortunately, absence in the customer of clear ideas about the appearance of this apparatus, large overloading of firm by the current work, and also disease and death of M.L.Mil did not make it possible to immediately personify new concept into the life.
To the deep design development of combat rotorcraft Mi-28 (article 280) the colleagues of MVZ im. M.L.Mil under the management of new chief designer M.N.Tishchenko returned in 1972 ; when in the USA already had conducted studies according to the program of analogous army helicopter- attack aircraft [AAN]. Chief designer in the early stages was M.V.Olshevets. The command of the Soviet Air Force formed by this time basic requirements for the promising machine. Rotorcraft had to serve as supporting means of land forces in the battlefield, destruction of tanks and another armored technology, tracking of helicopter landings, fight with the helicopters of enemy.
As the basic weapon it was intended to use guided missiles of anti-tank complex "Sturm" (up to eight rockets) and 30-mm mobile gun. The overall mass of combat load was evaluated at 1200 kg. flight deck, which consists of the pilot and the operator, and the basic aggregates of helicopter had to have protection from defeat the weapon of caliber 7.62 and 12.7 mm. The flight complex was to ensure the operation at any time, twenty-four hours a day in any meteorological conditions. The maximum speed of machine was planned 380-420 km/h.
The designers of MVZ im. M.L.Mil conducted the aerodynamic, strength and weight designs of promising projects, worked the diverse variants of power plants, diagrams and layouts Mi-28. Since the customer required the equipment of the helicopter with a system of escape, and the practice of the flight tests, carried out at the firm, showed the complexity of guaranteeing the safe escape from the blades. Thus the developers examined as the priority the version of the twin-screw rotorcraft of transverse diagram. It not only guaranteed safe ejection out of the disks of screws, but also he made it possible to include in wing construction of rotorcraft.
In 1973, MVZ performed the design of this machine with a takeoff mass of up to 11.5 t, equipped with two TVZ-117F engines with a power of 2800 hp each, by two rotors with a diameter of 10.3 m and by a pushing propeller. Experimental production constructed the appropriate mock-up, in the divisions of OKB the aggregates and systems were studied.
In the middle the 1970's the customer reexamined the concept of the application of combat helicopters. The tactics of military operations (by analogy with the attack aircraft) at a relatively high altitude and the speed yielded the place for the tactics of actions at the low altitudes with the diffraction of area relief, which ensured high viability in the battlefield to helicopter.
In connection with this the designers OF [MVZ] at the beginning of the 70's by way of initiative developed engineering designs of a number of combat helicopters without the additional propulsive means. Among them - the versions of the helicopters: twin-screw transverse diagram with the rotors with a diameter of 8,25 m and two engines GTD (gas-turbine engine) -10[Fp] with a power of 1950 hp each; single-rotor design with the diameter of the rotor of 14,25 m and two engines GTD -10[Fp]; single-rotor design with the rotor with a diameter of 16 m and two engines [TV]3-117[F]. Last version was acknowledged most promising for Mi-28. The twin-screw coaxial diagram of [milevtsy] was not examined because of the fear of the possibility of [skhlestyvaniya] of the blades of rotors with the battle maneuvering.
The layout of the rotorcraft made it possible to substantially increase load ratio and combat load, and to also simplify construction. The adoption of the tactics of conducting military operations at low altitudes allowed, furthermore, to forego the installation of ejection system. Studies showed that with the defeat of helicopter at the low altitudes in crew it did not have time for ejection - it was necessary to design for the strength of machine frame and means of survival. Concepts of the use of the safely deformed constructions, energy-consuming chassis and energy-consuming armchairs conceived in the same years created prerequisites for guaranteeing the survival of the crew of the hit helicopter without requiring ejection. Based on this, designers preferred to return to structurally the simpler classical single-rotor design. As the power plant they selected the modification of the powerful, reliable and already mastered by industry engines TVZ-117.
The search for the most rational design of the helicopter was accompanied by the agreement of requirements for the weapon system, the aiming-piloting- navigation complex and other component product, by testing of model in wind tunnel in the wind tunnel, by the forming of the methods of estimation and by the determination of the methods of increasing in the combat vitality and viability, reduction in distinctness, that were being carried out in the specialized scientific research, experimental-design and flight-test organizations.
The basic from the very beginning designs became TsAGI (Central Institute of Aerohydrodynamics im. N Ye Zhukovskiy), Leah, VIAM (All-Union Scientific Research Institute of Aviation Materials), [NIIAS], [GNIKI] VVS, Kolomna KB of machine building, [TSKB] "falcon", [Ramenskoe] instrument-making KB [MAP] and other to the development of promising aiming-piloting- navigation complex and armament for the combat helicopter with each year was drawn increasingly more organizations of customer, ministries aviation, defense, radio-technical and other branches of industry. Design Mi-28 gradually acquired the nature of the national comprehensive program, compared in the complexity of the decided tasks with the building of new promising combat aircraft.
The design of the Mi-28 gradually acquired the nature of the national comprehensive program, compared in the complexity of the decided tasks with the building of new promising combat aircraft. By 1976 the features of the Mi-28 in essence were determined. All works on the combat vehicle headed the deputy chief designer A.N.Ivanov, the responsible chief designer assigned M.V.Vaynberg. To it was subordinated the entire group of the chief designers, each of whom answered for the separate direction of massive program. Developed at MVZ im. M.L.Mil, the technical proposal obtained the positive estimation of customer. The circle of co-executors on the systems and the complexes was formed.
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