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  ..[ ].. > > ( ) ( Department of General military subjec
 


Mi-28 Helicopter Gunship

( ) ( Department of General military subjec


 

18-01-10, 01:22 PM

  : 1
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Mi-28 Helicopter Gunship



 

Having a classic single-rotor layout, Mi-28, a two-seat battle helicopter, is intended for search and destroy missions against enemy armored vehicles and infantry, and also low-speed air targets, on ranges of direct visibility in easy and moderate heavy weather conditions at the presence of enemy counter efforts.

The helicopters construction has the single-rotor layout with the anti-torque rotor, two gas-turbine engines (GTE), the tricycle landing gear, and the stub wings.

Its semi-monocoque all-****l fuselage is made of aluminum-lithium alloys composite materials being widely used. The fuselage of Mi-28 consists of the nose and central compartments, it also includes the tail boom and the anti-torque rotor pylon. In the nose, there are two separate armored compartments of the crew cabin where seats of the navigator/weapons operator (in front) and the pilot (above and behind) are located. The cockpits of the pilot and the navigator-operator are separated by means of an armored fence. The navigators door is on the left board, and the pilots one is on the right side. The doors and transparencies are equipped with emergency release automatics. The crew cockpit is formed by flat surfaces and fully armored by means of lightweight titanium armor with outside ceramic tiles and the flare-proof armored transparency withstanding direct impact by 12.7mm bullets. Damaged tiles of the armor can be replaced. The crew rescue system at low altitudes consists of energy absorbing seats which are fitted with a system of attraction the crew to the seats in order to put them into the ready position. On high altitudes the crew is able to escape the helicopter by means of parachutes through the side doors. At emergency escape from the cockpit, special gangways, providing impact protection against the landing wheels, are inflated under the doors.

The integrated surveillance and fire control system KOPS and a frame of the gun unit are fixed on the stabilized platform in front and beneath the nose. The electrical equipment, and the targeting, piloting and navigation system are located under the pilot floor.

The main gearbox, the air mover, the auxiliary power unit, the hydraulic unit, and the conditioning system assemblies are mounted on the ceiling panel of the central compartment of the fuselage. Engines and angle gears together with the wing consoles are installed on the ceiling panel and the console elements of the frames at the right and at the left of the symmetry axis. Hardware blocks are placed onto the container of fuel tanks located in the lower part of the fuselage. The heaviest assemblies are arranged near the center of gravity that increases manoeuvrability of Mi-28. The rear compartment of the radio-equipment has free spaces providing sufficient capacity that allows to use it as a cargo compartment (to transport airfield equipment in case of re-deployment of the helicopter or for evacuation of a crew of another helicopter). The compartment is accessible through the door and the drop ladder located on the left board. Easy and convenient maintenance of systems and equipment of the helicopter is achieved by means of multiple access doors located on the fuselage boards. Lower arrangement of the tail boom protects it from touching by the main rotor blades at a quick maneuver. The rear part of the anti-torque rotor pylon is constructed as a fixed rudder, inside of which a cable run is placed for the anti-torque rotor and a horizontal stabilizer control. The stabilizer is fixed in the upper part of the tail boom. The tail landing gear is located under its lower part. The control of the stabilizer is connected to the lever of the main rotor collective pitch.

The helicopter is equipped with the cantilever type wing with small extension, 4.88m span, mid, with negative transverse V; it has the torsion box structure made of aluminum alloys, nose flap and tail part made of composite materials. The wing provides relief for the main rotor, and it is used to suspend missiles, guns and machine guns, bomb loads, and additional fuel tanks by means of four units located under the wing and on its two tips. In emergency, the wing can be thrown off.

The landing gear is of tricycle non-retractable type. The construction of the landing gears includes oil-gas dampers with additional emergency stroke which provide decreasing of overloads to the level of physiological tolerance of the crew in case of strike at landing with vertical velocity of 12m/s. The lever-type main gears allow to adjust clearance of the helicopter. Wheels of the main gears have pressure of 0.53MPa. The landing gear tread is 2.29m.

The main rotor has 5 blades. The blades have rectangle shape in a plane cut, and the blade chord is 0.67m. The tips of the blades have arrow-shaped leading edges. The blades have glass-fiber longerone manufactured on CNC machines by the method of spiral winding, with honeycombed glass-fiber sections attached to it; along the blade nose there is an erosion-protective titanium splice plate with an electric anti-icing system. The main rotor hub construction consists of a titanium case with five outrigger spherical elastomeric joints. In movable joints of the hub ****lfluoraplastic and ****ile bearings are used. Rotation speed of the main rotor is 242rpm, circumferential speed of the blade tips is 216m/s.

The four-blade tail rotor of 3.84m diameter is made up of two two-blade rotors with elastomer horizontal joints. Its hub consists of two modules installed one above another on slots of the boss. Each module represents two blade arms coupling. The blade consists of the glass-fiber longerone and the tail part made of the honeycomb block and the glass-fiber skin. The blades of the main rotor and the tail rotor are equipped with the anti-icing electric heating system. Blades of the tail rotors are installed under the angles of 45 and 135 in order to decrease the level of noise. The blades have rectangular shape in a plane view. The length of the blade chords is 0.24m.

The power unit consists of two turboshaft engines with TVZ-117VM free turbines. Each with the takeoff power of 1950h.p.; the engines are installed in separate gondolas on both sides of the fuselage and are provided with modified electronic control system. Independent work of the engines ensures the possibility of flight with one operating engine. The auxiliary power unit, GTE located behind the main rotor reducer on the top of the fuselage, supplies compressed air that is used to start the engines and to drive the systems. The air inlets of the GTE have dust protection units, while nozzles are cooled by the air flow supplied through the air inlets located on each side of pods and mixed with the gas flow of the GTE to decrease IR signature.

The fuel system of Mi-28 consists of two autonomous symmetric systems for each engine with automatic cross feeding and pipage. The system includes three tanks (two feeder tanks, one for each engine, and one common tank) which are placed inside the fuel tank container with walls protected by foam rubber. The fuel tanks are also filled with foam polyurethane providing explosion protection. External fuel tanks can be installed for ferry flights.

Two UR-28 angle gears transferring torque from the engines to the VR-28 main gearbox and operating as the first reducing stages is the particular feature of the helicopter transmission.

The control system is mechanical, with hydraulic boosters. The helicopter control is maximally integrated: the flight controls are located in the pilot cabin, and the weapon controls are in the navigator/weapons operator cabin. The control system uses four integrated steering linkages functioning as the hydraulic boosters and a servo unit of the autopilot. Consisting of two independent systems, the hydraulic system of Mi-28 feeds the combined steering linkages of the control systems and a hydraulic buffer in the tracking guide system. The working pressure in the system is 15.2 MPa.

The equipment of the helicopter also includes the pneumatic system, the air conditioning system and the oxygen equipment.

Two generators driven from the main gearbox provide 208V AC power supply to the alternating current electric system.

The equipment comprises the integrated surveillance and fire control system of high resolution and high level of automation on a gyro-stabilized platform with the horizontal mobility of 110 and the elevation mobility from +13to -40 for targeting of antitank guided missiles and gunfire control. In the day version the system has two optical channels with wide and narrow angle of vision (3x and 13x zoom accordingly). An optical-television channel (with TV system for low illumination levels and 20x zoom) is provided for night missions.

The laser distance meter / target designator determinates the distance to the target and transfers the data to the computer to correct the gun fire and to launch both unguided air-to-surface missiles and guided missiles. The crew has the possibility to use night-vision goggles. The hardware of the pilot cabin includes the head-up display and the helmet-mounted target designator for the gun control. The cabin of the navigator/weapons operator is equipped with the ELT screen displaying data of the electro-optical system. The helicopter is equipped with the electronic suppression system Vitebsk, IR suppression devices, and heat flare dispensers fitted inside the containers at the tips of the wing.

The armament of Mi-28 consists of the non-detachable movable gun mount NPPU-28 with the 2A42 30mm gun manufactured by the Tula Design Bureau for Instrument Engineering, and a system of detachable weapons suspended on racks of the wing pylons. Motion range of NPPU-28 is: 110 (azimuth); from +13 to -40 (elevation). Two modes of fire are provided: fire rate of 900 shots per minute against air targets, and 300 shots per minute against ground targets. The ammunition of 250 ****ls is located in two boxes with selective two-sided feed on a rotating part of the turret. The provision is made for suspending 16 Shturm-V anti-tank missiles with radio command guidance system or Ataka-V with radar guidance system which are destined to destroy not only ground targets, but also low-speed low-altitude air targets. Blocks of B-5V35, B-8V20 or B-13L1 unguided missiles, the GUV versatile helicopter pods in the machine gun and the grenade launcher variants, the KMGU-2 containers for small cargo elements with bombs and mines of small caliber can be fastened on the internal holders. The holders can also carry aerial bombs of 250kg and 500kg caliber or additional fuel tanks. In the ensuing years armory of Mi-28 was complimented with S-24B heavy unguided missiles, UPK-23-250 gun containers, and ZB-500 flame bombs.

The guided weapon (gun, ATGMs) is applied by the navigator/weapon operator from the front cabin. Unguided missiles can be launched from both cabins. Within the limits of direct visibility without zooming optics, the pilot also can target and fire the gun with the help of the head-up display or the helmet target designator.

The helicopter is equipped with fixtures for mine laying.

Protection of Mi-28 against guided missiles is provided by means of: the equipment for jamming countermeasures against radars and guided missiles with infrared and radar homing devices; the equipment for warning in case the helicopter is illuminated by enemy radars or laser designators; the device for releasing UV-26 jamming cartridges providing protection against missiles with infra-red homing heads.

Source: 1. Website Уголок неба

 

 


 

   

04-02-10, 09:19 AM

  : 2



 

thanked my brother Albarrazny for the wonderful participation of all-new and waiting .... Greetings

 

 


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