Vitality helicopter
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Vitality helicopter

The survivability of the helicopter structure

 

Concepts survivability

By helicopter survivability understand its ability to operate in accordance with the combat mission after the impact of enemy weapons. Combat survivability is as important parameter of the helicopter, as well as the range, capacity, speed, flight, and so on. D. Determining its combat effectiveness.

Ordnance used by helicopters, can be divided into percussion shells (small, artillery guns, rocket fuses with contact) and remote action.

Shells percussive hit (incapacitate) the helicopter when released into the vital parts that can be damaged by this type of projectile, for example, the crew, engines, parts management system, fuel system, the elements of weapons and so on. N. If you get a few shells may result by accumulating damage, although each of the fallen projectiles alone does not take the helicopter out of action.

Shells remote actions undermined at some distance from the helicopter, provides a high probability of failure. Damaging factor in this case is a stream of fragments, rods, and having a specific density of kinetic energy.

Shards as percussion shells, can affect the helicopter entering the vital part of it. In addition, the intensive stream of debris can affect the glider and helicopter which is derived from the system only as a result of accumulation of damages.

Known kinds of destructive action of debris flow: mechanical action, aeroudar and hammer.

The mechanical action of the fragments is the formation of holes, weakening the structure, and its destruction under the influence of external loads. The most dangerous defeat compressed panels. structure (tail boom empennage, wings, and so on. d, resulting in loss of stability.

Aeroudar characterized by the formation of a shock wave inside a closed compartment design when hit by fragments with high energy. This is detached panel construction, the destruction of the walls of the side members, and so on. D.

Water hammer occurs when the debris in fuel tanks and other containers filled with liquid. If water hammer is the destruction of not only the tank, but also the surrounding areas due to the structure of the shock wave. These types of lesions are most dangerous to the construction of closed compartments of relatively small volumes.

The specific reasons for the decommissioning of the helicopter may be the following:

  • - death or injury of the crew;
  • - defeat of the main structural elements of the airframe leading to the destruction of any part of the helicopter in flight;
  • - damage to elements of the carrier system or transmission;
  • - the occurrence of a fire;
  • - defeat of the propulsion system;
  • - loss of fuel or interruption of its supply to engines;
  • - loss of controllability of the helicopter;
  • - defeat of the main equipment, without which it is impossible to perform a combat mission;
  • - defeat of weapons and sights.

 

A quantitative measure of survivability of the aircraft is considered to be the probability that it will not be struck when exposed to a specific means of destruction in the specific conditions of combat use.

Probability is not the defeat of the helicopter depends on the type and power of the damaging agents, shooting direction, the layout of the helicopter, its design, structural measures aimed at improving its survivability. The definition of this magnitude is a very complex task and beyond the scope of this tutorial.

 

Design and layout measures to improve the survivability of helicopters

Selection of specific measures to improve the survivability of the helicopter is determined by the terms of its combat use, as well as the means of destruction, which most likely will be used against him.

As the use of fighter aircraft against helicopters ineffective, the main danger for them is the fire of small arms, small-caliber anti-aircraft artillery, rockets from the ground. It is included in the layout of helicopters, the development of protective measures. However, we must bear inmean that the combat use of helicopters in mountainous terrain and possible fire from above. In addition, currently already working on the issues of helicopters tactics of air combat, which would require changing the approach to ensure their survivability.

One of the most important measures to improve combat survivability is the protection of the crew. For this, when assembling a helicopter, they try to arrange the structural elements of the structure, massive aggregates so that they shield the crew members from the side of the most probable directions of attack. It is used to book crew jobs, in particular, transparent armor. Helicopters of fire support can use bulletproof vests and helmets for crew members. To protect against secondary fragments formed when the projectile is destroyed by structural elements and equipment of the cabin, the lining of its internal surface with special materials can be used.

Against helicopters are widely used missiles "land - air" with thermal homing, so it is highly probable defeat of their propulsion systems, creating a significant thermal radiation.

To improve the survivability of propulsion systems on their output devices used screen-exhaust device, reducing heat radiation, special equipment may be interfering with thermal homing missiles, booking the most vulnerable sites. In terms of layout engines advisable to diversity farther apart for isdlyucheniya simultaneous destruction of a missile or projectile.

The most critical element of the support system is a helicopter blade HB as its destruction will inevitably lead to disaster. To improve the survivability of the blades developed design with several spars.

The greatest danger in the fire relation are fuel, oil and hydraulic systems.

In order to increase the combat survivability of the fuel system, neutral gas systems are used that ensure the displacement of oxygen from the over-fuel space of the tanks and the fire-extinguishing system. Widely used filling of fuel tanks with a porous material (sponge) separating the vapor-air mixture into separate cells, loosely connected with each other, which helps suppress the ignition foci1 when the tanks are damaged. To reduce fuel losses and the possibility of a fire, the tested fuel tanks are used, in the construction of which a special protective layer is used, which helps tighten the holes.

Quite a danger of hydraulic pipelines under high pressure, as this happens vigorous spray of liquid that makes it easier to fire.

For povysheniya- vitality of all major units supply hydraulic circuit are performed in a single monolithic block. It desirably the application of non-flammable liquids.

In order to protect the vital easily vulnerable units of various systems, equipment, weapons, engines widely used screening them with other, more resistant units or structural elements, as well as reservations.

One way to improve combat survivability is redundancy of vital units: the use of multiple motors instead of one, several postings control of pipelines, energy sources, and so on. D.

 

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