Como funcionam os helicópteros Apache

Autor: 
Tom Harris

The helicopters have military and civilian uses such as transport of troops, infantry support, transport entrepreneurs, transport of goods, etc. The Apache helicopter is a revolutionary development in the history of warfare. It is essentially a flying tank. It is designed to withstand heavy attacks to hit the enemy and causing heavy damage. He can aim at specific targets, day or night, even in critical weather conditions. 

In this article, we the flight systems of the Apache, as well as weapons systems, sensors, and shielding. Individually, these components are already remarkable pieces in technology. Combined, form an incredible flying machine - the deadliest helicopter created today.

Basically, Apache works the same way as any other helicopter : it has two rotors that spin several blades . A shovel is an inclined airfoil, like the wing of a plane . As the air accelerates, each blade generates a support (see How Airplanes Work to find out how the support is generated).

apache helicopter diagram

The main rotor attached to the top of the helicopter, four rotating blades 6 m. The maneuver the helicopter pilot adjusting mechanism of the swash plate, which modifies the pitch of each blade to increase the lift. Adjusting the pitch equally for all blades, raise or lower the helicopter. Changing the pace as the blades make their way around the rotation cycle, an uneven lift is created, causing the helicopter to tilt and fly in a particular direction (see How Helicopters Work for a detailed explanation).

When the main rotor rotates, it exerts a rotational force on the helicopter as a whole. The tail rotor blades work against this force as push the tail in the opposite direction. Changing the slope of the rear blades, the pilot can rotate the helicopter in any direction or keep it in a certain. Apache has two tail rotors, each with two blades.

rotor assembly on an AH-64A Apache
Photo courtesy Department of Defense The rotor assembly of the Apache AH-64A

The new Apache uses two General Electric engines turboárvore T700-GE-701C  (in English), approximately 1,700 horsepower each. Each engine turns a tree that is connected to a gearbox simple. The gearbox changes the rotation angle of approximately 90 degrees and passes the power for transmission. The transmission transmits power to the main rotor assembly and a long tree that goes to the tail rotor. The rotor is optimized to provide more agility than an ordinary helicopter.

The backbone of each blade consists of five stainless steel arms called beams , which are surrounded by a plastic skeleton reinforced with glass fiber. The edge of each blade is covered with a leakage of solid graphite composite, while the leading edge is made ​​of titanium. Titanium is strong enough to endure little touches in trees and other smaller objects, which is desirable flights at low altitude (close to the ground, "copy the ground"). The Apaches have to fly that way to peek targets and prevent attacks. The rear wing tail helps stabilize the helicopter during flight at low altitude and also while hovering.

Apache helicopter blades and wings detach for easier transport
Photo courtesy Department of Defense blades and wings of Apache are disassembled for easy transport

 

Who uses Apache and who manufactures it?

The Apache is the primary attack helicopter of the United States arsenal. Other countries, including the UK, Israel and Saudi Arabia, Apaches also added to its fleet.

The first series of Apaches, developed by Hughes Helicopters in the 70s, went into operation in 1985 The United States Army is gradually changing this unique project known as Apache AH-64A Apache Longbow by AH-64D, more advanced. In 1984, McDonnell Douglas purchased Hughes Helicopters and in 1997, the Boeing  (in English) merged with McDonnell Douglas. Today, Boeing manufactures the Apache helicopters and GKN Westland Helicopters  (in English) based in the UK, makes the British version of Apache, the WAH-64.

Hellfire missiles
The main function of Apache is heavily armored ground targets to reach, such as tanks and bunkers. To perform this function, it is necessary heavy artillery, as well as an extremely sophisticated to achieve the target sighting system.

The main weapon of the Apache, the Hellfire missile , fulfills these requirements. Each missile has its own computer guide, steering control and propulsion system. The missile is a high-explosive warhead loaded with copper and powerful enough to destroy the strongest tank shroud that may exist.

An apache fires two Hellfire missiles in a training exercise
Photo courtesy Department of Defense American An Apache fires two Hellfire missiles at a training exercise

Apache loads the missiles in four rails shooting arrested the brackets mounted on each wing. There are two brackets in each wing and each can hold four missiles, so - Apache can carry up to 16 missiles at a time. Prior to launch, each missile receives instructions directly from the helicopter computer. When the computer transmits the trigger signal, the missile releases the propellant. When the hot propellant generates about 230 pounds of force, the missile is launched from the rail. As the missile accelerates, the acceleration force triggers the arming mechanism. When the missile makes contact with the target, an impact sensor releases the warhead.

The design of the original Hellfire uses a laser guidance system to reach its target. In this system, the Apache gunner aims a laser beam of high intensity toward the target (in some situations, land forces can operate the laser instead of the gunner). The laser pulses on and off in a particular coded pattern.

apache helicopter hellfire missiles and four
Photo courtesy American Army Each set of rails supports four Hellfire missiles

Before the trigger signal, the computer tells the Apache specific pattern of the laser pulse to control the missile system. The missile has a searcher laser at its tip, which detects the laser light reflected by the target. Thus, the missile can "see" where the target is. The guidance system calculates which way the missile should do to go directly toward the reflected laser light. To change course, the guidance system moves the fins direction of flight of the missile, the same way that an airplane.

Apache helicopter firing missiles
Photo courtesy of the American Army

The Hellfire laser-guided system is quite effective, but has some issues that should be considered:

  • concealment by clouds or obstacles can block the laser beam, causing the missile can not reach the target;
  • if the missile passes through a cloud, he may lose sight of the target;
  • the helicopter (or the ground team that is monitoring the target) have to maintain the fixed laser on the target until the missile make contact. This means that the helicopter has to be discovered, vulnerable to attack.

The Hellfire II , Longbow Apache helicopters used in corrects these flaws. Instead of a laser search system, the missile has a search system using radar . The radar helicopter located the target and the missile pointed at him. As radio waves are not obscured by clouds or obstacles, the missile is more likely to hit the target. As he did not have to keep focused laser on the target, the helicopter can fire the missile and immediately seek cover.

Rockets and automatic cannon
Apaches usually fly with two rocket launchers Hydra , instead of two sets of Hellfire missiles. Each rocket launcher carries 19 folding fin aerial rockets of 7 cm , arrested the launch tubes. To fire the rocket launcher triggers an actuator at the rear of the tube. The Apache gunner can fire a rocket at a time or throw them into groups. Flight fins open to stabilize the rocket when it leaves the launcher.

hydra hellfire missile and rocket launch rails on AH-64A Apache helicopter> <br> <font size =

Photo courtesy Department of Defense The Hydra rocket launcher (right) and the rails of the Hellfire missile (left) in the AH-64A Apache helicopter

The rockets work with varieties of models of warheads. For example: can be armed with high explosives or only with materials that produce smoke. In one embodiment, the warhead delivery several submunitions , small bombs that separate from the rocket in the air and fall on the targets below.

The gunner sight short-range targets with M230 automatic cannon 30 mm attached to a turret under the nose of the helicopter. The gunner aim the cannon using a sophisticated computer system in the cabin. The computer controls the hydraulic mechanism moving the tower side to side and top to bottom.

M-230A1 30-mm automatic cannon on an AH-64A Apache
Photo courtesy Department of Defense American Auto M-230A1 30mm cannon on an Apache AH-64A

The automatic cannon is a model cannon current , powered by an electric motor . The motor rotates the chain, which slides the whole plate forward and backward, in order to load, fire, extract and eject cartridges. This is different from a machine gun common, that uses the force of explosion of the cartridge.

Cartridges travel comb above the canyon via a ramp, until you reach the chamber. The magazine accepts maximum 1,200 bullets and the cannon can fire 600-650 rounds per minuto.Os cannons firing highly explosive charges designed to pierce light armor.

On the next page, we'll look at the target location of the gun system as well as the other main controls of the Apache.