Introduction The Apache helicopter is a revolutionary development in the history of war.It is essentially a flying tank in which it is known as a helicopter designed to survive heavy attack and inflict massive damage. It can zero in on specific targets, day or night, even in terrible weather. As you might expect, it is a terrifying machine to ground forces. This helicopter is a military helicopter designed for use by the United States Army. In addition to being used by the American military, this design is also utilized by several other militaries, including those of Greece, Israel, and the Netherlands. The Apache design is revolutionary in the world of military helicopters, as the helicopter essentially acts as an airborne tank, with heavy weapons systems which are capable of targeting heavily-armored ground targets. The Apache helicopter is also one tough bird: it's extremely difficult to bring down an Apache. The design for the Apache was developed by Hughes Helicopters in the 1980s. The AH64 Apache, as it is formally known, is manufactured by Boeing Aircraft. However, the Apache twin-engine army attack helicopter is developed by McDonnell Douglas (Boeing). The helicopter's name reflects a longstanding military tradition of referencing Native American culture in the names for military helicopter, and “Apache” is an apt name for this aircraft, as this Native American tribe is famed for its militant nature and skilled performance in war. This helicopter is designed for offensive attack, and it can provide air support to the Army on the ground, or actively seek out and eliminate targets, depending on the mission. Each Apache helicopter has two cockpits, with a complete set of controls for both a pilot and a gunner the gunner sits in the forward cockpit and the pilot sits in the back. Combined together. weapons systems.in each cockpit. sensor systems and armor systems. It was used in Operation Desert Storm and has supported low intensity and peacekeeping operations worldwide including Turkey. In this report. .000 have been exported. Bosnia and Kosovo. we'll look at the Apache's amazing flight systems. Under normal conditions. they make up an unbelievable fighting machine which can be described as the most lethal helicopter ever created. these components are remarkable pieces of technology. The US Army has more than 800 Apaches in service. Individually. The Apache was first used in combat in 1989 in the US military action in Panama. but either officer can take over in the event that one is disabled. and more than 1. can go forward and backward like a train. It also adds the ability to go up and down. However. These extra degrees of freedom and the skill you must have to master them is what makes helicopters so exciting. The amazing flexibility of helicopters means that they can fly almost anywhere. The pilot has to think in three dimensions and must use both arms and both legs constantly to keep a helicopter in the air! Piloting a helicopter requires a great deal of training and skill. The entire aircraft can rotate in the air. A helicopter can hover motionless in the air In a car or a plane.Helicopter Basics Helicopters are the most versatile flying machines in existence today. There are only two directions that a train can travel in -. as well as continuous attention to the machine. To control a helicopter. which controls the up and down motion of the helicopter (and also controls engine speed). cars and airplanes. The other hand grasps a control called the collective. of course. While you are traveling in either direction you can also turn left or right: A plane can move forward and turn left or right. In a helicopter. A car. which controls the lateral direction of the helicopter (including forward. backward. This versatility gives the pilot complete access to three-dimensional space in away that no airplane can. To understand how helicopters work and also why they are so complicated to fly. HA helicopter can do three things that an airplane cannot: A helicopter can fly backwards. The pilot's feet rest on pedals . it also means that flying the machines is complicated. the vehicle must be moving in order to turn. it is helpful to compare the abilities of a helicopter with those of trains.forward and reverse. you can move laterally in any direction or you can rotate 360 degrees. but it also makes them complex. left and right). one hand grasps a control called the cyclic. counteracting the engine's desire to spin the body. The rotating wings of a helicopter are shaped just like the airfoils of an airplane wing. This arrangement works really well until the moment the vehicle leaves the ground. in the absence of anything to stop it. It takes both hands and both feet to fly a helicopter! Imagine that we would like to create a machine that can simply fly straight upward. So you can mount two or more wings on a central shaft and spin the shaft. A rotary motion is the easiest way to keep a wing in continuous motion.that control the tail rotor. Normally. To keep the body from spinning. which allows the helicopter to rotate in either direction on its axis. By producing thrust in a sideways direction. The engine's drive shaft can connect through a transmission to the main rotor shaft. the tail rotor keeps the body of the helicopter from spinning. the wings start to develop lift. the body will spin in an opposite direction to the main rotor. If you are going to provide the upward force with a wing. The helicopter's rotating wing assembly is normally called the main rotor. If you give the main rotor wings a slight angle of attack on the shaft and spin the shaft. Let's not even worry about getting back down for the moment -. The tail rotor produces thrust just like an airplane's propeller does. The usual way to provide a force to the body of the vehicle is to attach another set of rotating wings to a long boom. then the wing has to be in motion in order to create lift. So. Reciprocating gasoline engines and gas turbine engines are the most common types. In order to spin the shaft with enough force to lift a human being and the vehicle. but generally the wings on a helicopter's rotor are narrow and thin because they must spin so quickly. the tail rotor is driven by a long drive shaft that . you need an engine of some sort. These wings are known as the tail rotor. At that moment. Wings create lift by deflecting air downward and benefiting from the equal and opposite reaction that result straight upward. you need to apply a force to it.up is all that matters. much like the blades on a ceiling fan. there is nothing to keep the engine (and therefore the body of the vehicle) from spinning just like the main rotor does. the swash plate assembly can change the angle of both blades simultaneously. The main rotor hub. The adjustability of the tail rotor is straightforward -. including forward. Under the direction of the cyclic control. The swash plate assembly has two primary roles: Under the direction of the collective control. What you end up with is a vehicle that looks something like this: A helicopter's main rotor is the most important part of the vehicle. To handle all of these tasks. has to be extremely strong as well as highly adjustable. The swash plate assembly is the component that provides the adjustability. as well as the control that allows the helicopter to move laterally.what you want is the ability to change the angle of attack on the tail rotor wings so that you can use the tail rotor to rotate the helicopter on the drive shaft's axis. the rotor must first be incredibly strong. make turns and change altitude. It provides the lift that allows the helicopter to fly. where the rotor's drive shaft and blades connect. and right. Doing this increases or decreases the lift that the main rotor supplies to the vehicle. The adjustability is provided by a device called the swash plate assembly. This allows the helicopter to move in any direction around a 360degree circle.runs from the main rotor's transmission back through the tail boom to a small transmission at the tail rotor. It must also be able to adjust the angle of the rotor blades with each revolution of the hub. left. Basic Parts of a Helicopter . the swash plate assembly can change the angle of the blades individually as they revolve. backward. allowing the helicopter to gain or lose altitude. which are surrounded by a fiberglass skeleton. By changing the pitch of the rear blades.Power and Flight At its core. The gearbox shifts the angle of rotation about 90 degrees and passes the power on to the transmission. each blade generates lift. boasting about 1. while the leading edge is made of titanium. A blade is a tilted airfoil. Each engine turns a drive shaft. which is connected to a simple gearbox. an Apache works pretty much the same way as any other helicopter. which is helpful in "nap-of-the-earth" flying (zipping along just above the contours of . As the main rotor spins. just like an airplane wing. Adjusting the pitch equally for all blades lifts the helicopter straight up and down.they push the tail boom in the opposite direction. As it speeds through the air. The newest Apache sports twin General Electric T700-GE-701Cturboshaft engines. it exerts a rotation force on the entire helicopter. attached to the top of the helicopter. The trailing edge of each blade is covered with a sturdy graphite composite material. the pilot can rotate the helicopter in either direction or keep it from turning at all. The titanium is strong enough to withstand brushes with trees and other minor obstacles. The rear rotor blades work against this force -. each with two blades.700 horsepower each. Changing the pitch as the blades make their way around the rotation cycle creates uneven lift. An Apache has double tail rotors. The pilot maneuvers the helicopter by adjusting a swash plate mechanism. The swash plate changes each blade's pitch (tilt) to increase lift. causing the helicopter to tilt and fly in a particular direction. called spars. It has two rotors that spin several blades. spins four 20-foot(6-meter) blades. The rotor is optimized to provide much greater agility than you find in a typical helicopter. The core structure of each blade consists of five stainless steel arms. The transmission transmits the power to the main rotor assembly and a long shaft leading to the tail rotor. The main rotor. the Apache's advanced weaponry puts it in an entirely different class.the ground). As we'll see in the next few sections. Apache Helicopter Parts and Compenants . that the Apache is just a high-end helicopter. The rear tail wing helps stabilize the helicopter during nap-of-the-earth flight as well as during hovering. You could say. Apaches need to fly this way to sneak up on targets and to avoid attack. But that would be like calling James Bond's Aston Martin just a high-end car. based on all this information. and each pylon can support four missiles. you need an extremely sophisticated targeting system. The guidance system calculates which way the missile needs to turn in order to head straight for the reflected laser light. The missile has a laser seeker on its nose that detects the laser light reflecting off the target. Each missile is a miniature aircraft. complete with its own guidance computer. The Apache's primary weapon. so the Apache can carry as many as 16 missiles at a time. the guidance system moves the missile's flightfins. the Apache computer tells the missile's control system the specific pulse pattern of the laser. As the missile speeds up. you need some heavy firepower. When the missile makes contact with the target. To change course. the force of acceleration triggers the arming mechanism. the Hellfire missile. The original Hellfire design uses a laser guidance system to hit its mark. When the computer transmits the fire signal. the missile can see where the target is. meets these demands. the Apache gunner aims a high-intensity laser beam at the target (in some situations. the missile sets off the propellant. The Apache carries the missiles on four firing rails attached to pylons mounted to its wings. ground forces might operate the laser instead). the missile breaks free of the rail. but it has some significant drawbacks: . Before giving the firing signal.Hellfire Missiles The Apache's chief function is to take out heavily armored ground targets. The payload is a highexplosive. Before launching. To inflict this kind of damage. steering control and propulsion system. each missile receives instructions directly from the helicopter's computer. The laser-guided Hellfire system is highly effective. Once the burning propellant generates about 500 pounds of force. In this system. In this way. and to do it from a helicopter. The laser pulses on and off in a particular coded pattern. such as tanks and bunkers. There are two pylons on each wing. This is basically the same way an airplane steers. an impact sensor sets off the warhead. copper-lined-charge warhead powerful enough to burn through the heaviest tank armor in existence. Since it doesn't have to keep the laser focused on the target. This means the helicopter has to be out in the open. the missile is more likely to find its target. corrects these flaws. it can lose sight of the target. An Apache fires two Hellfire missiles in a training exercise. The helicopter's radar locates the target. Cloud cover or obstacles can block the laser beam so it never makes it to the target. . used in Apache Longbow helicopters. Since radio waves aren't obscured by clouds or obstacles. the missile has a radar seeker. Each rail set holds four Hellfire missiles. vulnerable to attack. and the missiles zero in on it. If the missile passes through a cloud. The helicopter (or a ground targeting crew) has to keep the laser fixed on the target until the missile makes contact. The Hellfire II. the helicopter can fire the missile and immediately find cover. Instead of a laser-seeking system. The rockets work with a variety of warhead designs. Each rocket launcher carries 19 folding-fin 2. and the gun can fire 600 to 650 rounds a minute. small bombs that separate from the rocket in the air and fall on targets below. The motor rotates the chain. powered by an electric motor.200 rounds.Rockets and Chain Guns Apaches usually fly with two Hydra rocket launchers in place of two of the Hellfire missile sets. For example. To fire the rockets. The cartridges travel from a magazine above the gun down a feed chute to the chamber. The Apache gunner can fire one rocket at a time or launch them in groups. they might be armed with high-power explosives or just smoke-producing materials.75-inchaerial rockets. The gunner aims the gun using a sophisticated computer system in the cockpit. which uses the force of the cartridge explosion or flying bullet to move the bolt. which slides the bolt assembly back and forth to load. extract and eject cartridges. The gunner engages close-range targets with M230 30-mm automatic cannon attached to a turret under the helicopter's nose. The computer controls hydraulics that swings the turret from side to side and up and down. the launcher triggers an igniter at the rear end of the tube. This is different from an ordinary machine gun. the warhead delivers several sub munitions. The automatic cannon is a chain gun design. secured in launching tubes. fire. The cannon fires high-explosive rounds designed to pierce light armor. The flight fins unfold to stabilize the rocket once it leaves the launcher. In one configuration. . The magazine holds a maximum of 1. .The Hydra rocket launcher (right) and Hellfire missile rails (left) on an AH64A Apache helicopter The M-230A1 30-mm automatic cannon on an AH-64A Apache. which detects the infrared light released by heated objects. The digital stabilization system fine-tunes the powerful hydraulic system to keep the helicopter flying smoothly. trucks. The controls manipulate the rotors using both a mechanical hydraulic system and a digital stabilization system. These digital displays are much easier to read than traditional instrument dials. The stabilization system can also keep the helicopter in an automatic hovering position for short periods of time. three display panels provide the pilot with most navigation and flight information. The night vision sensors work on the forward-looking infrared (FLIR) system. other aircraft and equipment to identify the general class of each potential target. As you might expect.Controls and Sensors The Apache cockpit is divided into two sections. The pilot's night vision sensor is attached to a rotating turret on top of the Apache's nose. The pilot and the gunner both use night vision sensors for night operations. The pilot sits in the rear section. and the co-pilot/gunner sits in the front section. The Longbow Apache detects surrounding ground forces. The computer pinpoints these targets on the pilot's and gunner's display panels. The radar dome uses millimeter radio waves that can make out the shape of anything in range. the pilot maneuvers the helicopter and the gunner aims and fires the weapons. The pilot simply presses buttons on the side of the display to find the information he or she needs. The pilot flies the Apache using collective and cyclic controls. one directly behind the other. The gunner's night vision . similar to ones you would find in any other helicopter. The radar signal processor compares these shapes to a database of tanks. On the Longbow Apache. One of the coolest things about the Apache is its sophisticated sensor equipment. aircraft and buildings using a radar dome mounted to the mast. Both sections of the cockpit include flight and firing controls in case one pilot needs to take over full operation. Each pilot can aim the sensors by simply moving his or her head! Manual controls are also available. The rear section is raised above the front section so the pilot can see clearly. Inside the Apache Longbow cockpit. .sensor is attached to a separate turret on the underside of the nose. The Apache has two cockpit sections: The pilot sits in the rear and the gunner sits in the front. of course. The computer transmits the night vision or video picture to a small display unit in each pilot's helmet. The lower turret also supports a normal video camera and a telescope. which the gunner uses during the day. Infrared sensors in the cockpit track how the pilot positions the helmet and relay this information to the turret control system. The video display projects the image onto a monocular lens in front of the pilot's right eye. Evasion and Armour The Apache's first line of defense against attack is keeping out of range. In a crash. The cooled exhaust then passes through a special filter. the helicopter is specifically designed to fly low to the ground. Some areas are also surrounded by Kevlar soft armor for extra protection. If the pilots pick up radar signals with the onboard scanner. to be sure. According to Boeing. The Black Hole infrared suppression system dissipates the heat of the engine exhaust by mixing it with air flowing around the helicopter. The cockpit is protected by layers of reinforced armor and bulletproof glass. As we saw earlier.7-mm rounds. The area surrounding the cockpit is designed to deform during collision. With these advanced systems. Flying an Apache into battle is extremely dangerous. they can activate a radar jammer to confuse the enemy. the crew has an excellent chance of surviving a crash. so the collision isn't as hard on the crew. agility and firepower. The Apache is also designed to evade heat-seeking missiles by reducing its infrared signature (the heat energy it releases). every part of the helicopter can survive 12. It is a deadly combination of strength. and vital engine and rotor components can withstand 23-mm fire. The Apache is also designed to evade enemy radar scanning. . armor and sensor equipment. it is a formidable opponent to almost everything else on the battlefield. hiding behind cover whenever possible. The Apache is heavily armored on all sides. which absorbs more heat. The Longbow also has an infrared jammer. The pilot and gunner seats are outfitted with heavy Kevlar armor. the deformation areas work like the crumple zones in a car -. which also absorbs the force of impact. but with all its weapons. which generates infrared energy of varying frequencies to confuse heat-seeking missiles.they absorb a lot of the impact force. but the cockpit canopy is extremely rigid. The sensor array on an Apache helicopter. .The Apache Longbow has a distinctive radar dome mounted to its mast. the following relationships must be true: Thrust = Drag Lift = Weight If. Straight and Level Flight In order for an airplane to fly straight and level. the plane will speed up. Similarly. thrust and drag. if the amount of lift drops below the weight of the airplane. . for any reason.Aerodynamic Forces We take a look at four basic aerodynamic forces: lift. the pilot can make the airplane climb. weight. the amount of drag becomes larger than the amount of thrust. the plane will slow down. the plane will descend. By increasing the lift. If the thrust is increased so that it is greater than the drag. Airplanes create thrust using propellers. It acts opposite to thrust. pulling air past the blades. which acts like a very powerful version of a household fan. Weight This one is the easiest. and is probably the trickiest of the four aerodynamic forces to explain without using alot of math. most of the lift required to keep the plane aloft is created by the wings (although some is created by other parts of the structure). the thrust is being created with a propeller. Every object on earth has weight (including air). Drag Drag is an aerodynamic force that resists the motion of an object moving through a fluid (air and water are both fluids). In the figure above. Lift Lift is the aerodynamic force that holds an airplane in the air.Thrust Thrust is an aerodynamic force that must be created by an airplane in order to overcome the drag (notice that thrust and drag act in opposite directions in the figure above). jet engines or rockets. . On airplanes. In this seminar I’ve tried to put forward some of the design features of the same.Conclusion With the design of the apache the very concept of helicopter itself has changed all over the world. But it can be surely emphasized that the Apache is the pioneer in the attack helicopter family. have rolled over their versions of attack helicopters. . Many countries like Russia. They replaced the main drawbacks of apache. Germany etc. com www.howstuffworks. 4. 5.apachehelicopters.helicopters.wikiepedia.org www.References: www.answers.com www. .com 1. 2.com 6. www. 3.com www.google.