seminar report

VISVESWARAYA TECHNOLOGICAL UNIVERSITYBELGAUM-590014

A Technical Seminar paper on

“THE TECHNOLOGIES INVOLVED IN APACHE HELICOPTER”

Submitted in partial fulfillment of the requirement of Bachelor of engineering in

Mechanical Engineering

By

JOSIAH PRINCE (1EP08ME042)

DEPARTMENT OF MECHANICAL ENGINEERING

EAST POINT COLLEGE OF ENGINEERING AND TECHNOLOGYBidarahalli, Virgonagar P.O, Bengaluru-560049

2011-2012

The APACHE HELICOPTER

EAST POINT COLLEGE OF ENGINEERING AND TECHNOLOGY

Bidarahalli, virgonagar P.O, Bangalore-560049

DEPARTMENT OF MECHANICAL ENGINEERINGCERTIFICATE

This is to certify that the Technical Seminar entitled “THE TECHNOLOGIES INVOLVED IN APACHE HELICOPTER” is carried out by JOSIAH PRINCE bearing USN 1EP08ME042 in partial fulfillment for the award of Degree of Bachelor of Engineering in MECHANICAL ENGINEERING Visveswaraya Technological University, Belgaum during the year 2011-2012. It is certified that all the deposited in the department library. The Technical Seminar report has been approved as it satisfied the academic requirements in respect to Technical Seminar prescribed for the Bachelor of Engineering Degree.

Signature of Co-ordinator Signature of HOD Signature of Principal (Mr. Sahadev) (Prof. H.R .Vittal) (DR. B.M Satish)

Dept. Of Mechanical Engg, EPCET


ACKNOWLEDGEMENT

The satisfaction and euphoria that accompany the successful completion of any task would be

incomplete without mention of the people who made it possible, whose constant guidance and

encouragement crowded our efforts with success.

I extend my sincere thanks to the management of “The East Point College of Engineering and

Technology” for their support.

I thank our principal Mr. B.M.SATISH for providing necessary resources.

I thank Prof. H.R.VITALA, Department of Mechanical for his efforts and motivation.

I also thank all the faculty members of Mechanical department for their support. I also thank all

non- teaching staff members for providing the necessary guidance, support, help and cooperation

without which the seminar would have been incomplete. My sincere thanks to all those who have

directly or indirectly supported us in all aspects, in bringing out this seminar efficiently and

successfully.

We would like to thank our parents for their constant moral support.

Above all I thank the Almighty for constantly helping me to overcome the hurdles and giving me

the strength to execute this seminar



ABSTRACTThe Apache Helicopter is a revolutionary development in the

history of war. It is essentially a flying tank- 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.

In this topic, we look at the Apache’s amazing flight systems,

engines, weapon systems, sensor systems and amour systems. Individually

these components are remarkable pieces of technology. Combined together

they make up an unbelievable fighting machine – the most lethal helicopter

ever created.



CONTENTS

INTRODUCTION……………………………………..02 HELICOPTER BASICS……………………………….03 BACKGROUND……………………………………....06 GENERAL CHARACTERISTICS……………………07 POWER AND FLIGHT……………………………….08 MAIN ROTOR ASSEMBLY…………………………11 HELLFIRE MISSILES………………………………..12 ROCKETS AND CHAIN GUNS……………………..14 CONTROL AND SENSORS…………………………16 EVASION AND ARMOURS………………………...19 CONCLUSION………………………………………..21 REFERENCE………………………………………….21


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INTRODUCTION TO APACHE HELICOPTER

The Apache helicopter is a revolutionary development in the history of war. It is essentially a flying tank -- 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. In this report, we'll look at the Apache's amazing flight systems, weapons systems, sensor systems and armor systems. Individually, these components are remarkable pieces of technology. Combined together, they make up an unbelievable fighting machine -- the most lethal helicopter ever created. The Apache is the primary attack helicopter in the U.S. arsenal. Other countries, including the United Kingdom, Israel and Saudi Arabia, have also added Apaches to their fleet.

The first series of Apaches, developed by Hughes Helicopters in the1970s, went into active service in 1985. The U.S. military is graduallyreplacing this original design, known as the AH-64A Apache, with the more advanced AH-64D Apache Longbow. In 1984, McDonnell Douglas purchased Hughes Helicopters, and in 1997, Boeing merged with McDonnell Douglas. Today, Boeing manufactures Apache helicopters, and the UK-based GKN Westland Helicopters manufacturers the English version of the Apache, theWAH-64.


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HELICOPTER BASICS Helicopters are the most versatile flying machines in existence today. This versatility gives the pilot complete access to three-dimensional space in a way that no airplane can.

The amazing flexibility of helicopters means that they can fly almostanywhere. However, it also means that flying the machines is complicated. 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, as well as continuous attention to the machine.

To understand how helicopters work and also why they are so complicated to fly, it is helpful to compare the abilities of a helicopter with those of trains, cars and airplanes. There are only two directions that a train can travel in -- forward and reverse. A car, of course, can go forward and backward like a train. While you are traveling in either direction you can also turn left or right:A plane can move forward and turn left or right. It also adds the abilityto go up and down. A helicopter can do three things that an airplane cannot: A helicopter can fly backwards. The entire aircraft can rotate in the air. A helicopter can hover motionless in the air.

In a car or a plane, the vehicle must be moving in order to turn. In aHelicopter, you can move laterally in any direction or you can rotate 360degrees. These extra degrees of freedom and the skill you must have to master them is what makes helicopters so exciting, but it also makes them complex.


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To control a helicopter, one hand grasps a control called the cyclic, which controls the lateral direction of the helicopter (including forward, backward, left and right). The other hand grasps a control called the collective, which controls the up and down motion of the helicopter (and also controls engine speed). The pilot's feet rest on pedals that control the tail rotor, which allows the helicopter to rotate in either direction on its axis. 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. Let's not even worry about getting back down for the moment -- up is all that matters. If you are going to provide the upward force with a wing, then the wing has to be in motion in order to create lift. Wings create lift by deflecting air downward and benefiting from the equal and opposite reaction that results straight upward.

A rotary motion is the easiest way to keep a wing in continuous motion. So you can mount two or more wings on a central shaft and spin the shaft, much like the blades on a ceiling fan. The rotating wings of a helicopter are shaped just like the airfoils of an airplane wing, but generally the wings on a helicopter's rotor are narrow and thin because they must spin so quickly. 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, the wings start to develop lift.

In order to spin the shaft with enough force to lift a human being and the vehicle, you need an engine of some sort. Reciprocating gasoline engines and gas turbine engines are the most common types. The engine's drive shaft can connect through a transmission to the main rotor shaft. This arrangement works really well until the moment the vehicle leaves the ground.

At that moment, there is nothing to keep the engine (and therefore the body of the vehicle) from spinning just like the main rotor does. So, in the absence of anything to stop it, the body will spin in an opposite direction to the main rotor. To keep the body from spinning, you need to apply a force to it.


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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. These wings are known as the tail rotor. The tail rotor produces thrust just like an airplane's propeller does. By producing thrust in a sideways direction, counteracting the engine's desire to spin the body, the tail rotor keeps the body of the helicopter from spinning. Normally, the tail rotor is driven by a long drive shaft that runs from the main rotor's transmission back through the tail boom to a small transmission at the tail rotor. 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. It provides the lift that allows the helicopter to fly, as well as the control that allows the helicopter to move laterally, make turns and change altitude. The adjustability of the tail rotor is straightforward -- 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. To handle all of these tasks, the rotor must first be incredibly strong. It must also be able to adjust the angle of the rotor blades with each revolution of the hub. The adjustability is provided by a device called the swash plate assembly. The main rotor hub, where the rotor's drive shaft and blades connect, has to be extremely strong as well as highly adjustable.


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BACKGROUND: The first fully equipped U.S. Army unit with the Apache Helicopter was fielded in November 1998. The U.S. Army fielded its first overseas Apache unit in October 2001. Between 1984 and 1997, Boeing produced 937 Apache’s for the U.S. Army, Egypt, Greece, Israel, Saudi Arabia and the United Arab Emirates. More than 1,800 Apaches have been delivered to customers around the world since the Apache went into production. The U.S. Army Apache fleet has accumulated more than 3 million flight hours since the first prototype aircraft flew in 1975.

CUSTOMERS: In all, 12 nations fly, have ordered or have selected Apache helicopters for their defense forces. The U.S. Army has ordered more than 600 Apache aircraft through multi-year contracts and follow-on purchases. Boeing delivered the first Apache to the Army in April 1997, and the first production AH-64D Apache Block III in October 2011. Follow-on orders and upgrades will keep the Apache in production well into the next decade.

International customers include Egypt, Greece, Israel, Japan, Kuwait, The Netherlands, Saudi Arabia, Singapore, the United Arab Emirates, and the United Kingdom. The first international Apache was delivered to the Royal Netherlands Air Force in May 1998, and the first international AH-64D Apache Block III will be delivered in 2012. More than 300 new and remanufactured international AH-64Ds have been delivered or are in production.

MISCELLANEOUS:


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The U.S. Army has fielded Apache Longbow units around the world. As of December 2011, U.S. Army Apache helicopters have logged nearly 900,000 combat hours in operations Enduring Freedom, Iraqi Freedom, and New Dawn, and in overseas contingency operations. Army aviators in the first battalion that will fly the Apache Block III helicopters have begun simulator and flight training, with the first class completing training in December 2011. The Apache performs across the full spectrum of operations as a force multiplier for Combatant Commanders and supports the safe return of troops.

GENERAL CHARACTERISTICS

LENGTH: 58.17ft (17.73m)

HEIGHT: 15.24ft (4.64m)

WING SPAN: 17.15ft (5.22m)

GROSS WEIGHT: 15,075lb (6838kg)

MAXIMUM FLIGHT SPEED: 153kt (284kmph)

CRUISE SPEED: 150kt (279kmph)

In the next topics, we'll look at the Apache's amazing flight systems, weapons systems, sensor systems and armor systems.

POWER AND FLIGHT

At its core, an Apache works pretty much the same way as any other


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helicopter. It has two rotors that spin several blades. A blade is a tilted airfoil, just like an airplane wing. As it speeds through the air, each blade generates lift.

The main rotor, attached to the top of the helicopter, spins four 20-foot (6-meter) blades. The pilot maneuvers the helicopter by adjusting a swash plate mechanism.

The swash plate assembly is the component that provides the adjustability. The swash plate assembly consists of two primary elements through which the rotor mast passes. One element is a disc, linked to the cyclic pitch control. This disc is capable of tilting in any direction but does not rotate as the rotor rotates.


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THE SWASH PLATE ASSEMBLY

The swash plate assembly has two primary roles: Under the direction of the collective control, the swash plate assembly can change the angle of both blades simultaneously. Doing this increases or decreases the lift that the main rotor supplies to the vehicle, allowing the helicopter to gain or lose altitude. Under the direction of the cyclic control, the swash plate assembly can change the angle of the blades individually as they revolve. This allows the helicopter to move in any direction around a 360-degree circle, including forward, backward, left and right.

The swash plate changes each blade's pitch (tilt) to increase lift. Adjusting the pitch equally for all blades lifts the helicopter straight up and down. Changing the pitch as the blades make their way around the rotation cycle creates uneven lift, causing the helicopter to tilt and fly in a particular direction. As the main rotor


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spins, it exerts a rotation force on the entire helicopter. The rear rotor blades work against this force -- they push the tail boom in the opposite direction. By changing the pitch of the rear blades, the pilot can rotate the helicopter in either direction or keep it from turning at all. An Apache has double tail rotors, each with two blades.

MAIN ROTOR ASSEMBLY The newest Apache sports twin General Electric T700-GE-701C turbo shaft engines, boasting about 1,700 horsepower each. Each engine turns a drive shaft,


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which is connected to a simple gearbox. The gearbox shifts the angle of rotation about 90 degrees and passes the power on to the transmission. The transmission transmits the power to the main rotor assembly and a long shaft leading to the tail rotor. 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, called spars, which are surrounded by a fiberglass skeleton. The trailing edge of each blade is covered with a sturdy graphite composite material, while the leading edge is made of titanium. The titanium is strong enough to withstand brushes with trees and other minor obstacles, which is helpful in "nap-of-the earth" flying (zipping along just above the contours of the ground). Apaches need to fly this way to sneak up on targets and to avoid attack. The rear tail wing helps stabilize the helicopter during nap-of-the-earth flight as well as during hovering. In the next few sections, we will see the Apache's advanced weaponry puts it in an entirely different class.

HELLFIRE MISSILES The Apache's chief function is to take out heavily armored ground


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targets, such as tanks and bunkers. To inflict this kind of damage, you need some heavy firepower, and to do it from a helicopter, you need an extremely sophisticated targeting system.

HOLDS FOUR HELLFIRE MISSILES

The Apache's primary weapon, the Hellfire missile, meets these demands. Each missile is a miniature aircraft, complete with its own guidance computer, steering control and propulsion system. The payload is a high explosive, copper-lined-charge warhead powerful enough to burn through the heaviest tank armor in existence.

The Apache carries the missiles on four firing rails attached to pylons mounted to its wings. There are two pylons on each wing, and each pylon can support four missiles, so the Apache can carry as many as 16 missiles at a time. Before launching, each missile receives instructions directly from the helicopter's computer. When the computer transmits the fire signal, the missile sets off the


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propellant. Once the burning propellant generates about 500 pounds of force, the missile breaks free of the rail. As the missile speeds up, the force of acceleration triggers the arming mechanism. When the missile makes contact with the target, an impact sensor sets off the warhead.

The original Hellfire design uses a laser guidance system to hit its mark. In this system, the Apache gunner aims a high-intensity laser beam at the target (in some situations, ground forces might operate the laser instead). The laser pulses on and off in a particular coded pattern.

Before giving the firing signal, the Apache computer tells the missile's control system the specific pulse pattern of the laser. The missile has a laser seeker on its nose that detects the laser light reflecting off the target. In this way, the missile can see where the target is. The guidance system calculates which way the missile needs to turn in order to head straight for the reflected laser light. To change course, the guidance system moves the missile's flight fins. This is basically the same way an airplane steers.

The laser-guided Hellfire system is highly effective, but it has some significant drawbacks:

Cloud cover or obstacles can block the laser beam so it never makes it to the target. If the missile passes through a cloud, it can lose sight of the target. The helicopter (or a ground targeting crew) has to keep the laser fixed on the target until the missile makes contact. This means the helicopter has to be out in the open, vulnerable to attack.

The Hellfire II, used in Apache Longbow helicopters, corrects these flaws. Instead of a laser-seeking system, the missile has a radar seeker. The helicopter's radar locates the target, and the missiles zero in on it. Since radio waves aren't obscured by clouds or obstacles, the missile is more likely to find its target. Since it doesn't have to keep the laser focused on the target, the helicopter can fire the missile and immediately find cover.


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ROCKETS & CHAIN GUNS

Apaches usually fly with two Hydra rocket launchers in place of two of the Hellfire missile sets. Each rocket launcher carries 19 folding-fin 2.75-inch aerial rockets, secured in launching tubes. To fire the rockets, the launcher triggers an igniter at the rear end of the tube. The Apache gunner can fire one rocket at a time or launch them in groups. The flight fins unfold to stabilize the rocket once it leaves the launcher.

The rockets work with a variety of warhead designs. For example, they might be armed with high-power explosives or just smoke-producing materials. In one configuration, the warhead delivers several sub munitions, small bombs that separate from the rocket in the air and fall on targets below. The gunner engages close-range targets with M230 30-mm automatic cannon attached to a turret under the helicopter's nose. The gunner aims the gun using a sophisticated computer system in the cockpit. The computer controls hydraulics that swings the turret from side to side and up and down.

The automatic cannon is a chain gun design, powered by an electricmotor. The motor rotates the chain, which slides the bolt assembly back and forth to load, fire, extract and eject cartridges. This is different from an ordinary machine gun, which uses the force of the cartridge explosion or flying bullet to move the bolt.


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M-230A1 30-mm automatic cannon

The cartridges travel from a magazine above the gun down a feed chute to the chamber. The magazine holds a maximum of 1,200 rounds, and the gun can fire 600 to 650 rounds a minute. The cannon fires high-explosive rounds designed to pierce light armor. One of the revolutionary features at the introduction of the Apache was its helmet mounted display, the Integrated Helmet and Display Sighting System (IHADSS) among other abilities the pilot or gunner can slave the helicopter's 30 mm automatic M230 Chain Gun to his helmet, making the gun track head movements to point at where he looks. The M230E1 can be alternatively fixed to a locked forward firing position, or controlled via the Target Acquisition and Designation System (TADS)

CONTROLS & SENSORS Dept. Of Mechanical Engg, EPCET

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The Apache cockpit is divided into two sections, one directly behind the other. The pilot sits in the rear section, and the co-pilot/gunner sits in the front section. As you might expect, the pilot maneuvers the helicopter and the gunner aims and fires the weapons. Both sections of the cockpit include flight and firing controls in case one pilot needs to take over full operation. The pilot sits in the rear and the gunner sits in the front.

The Apache’s two cockpit sections

The pilot flies the Apache using collective and cyclic controls, similar to ones you would find in any other helicopter. The controls manipulate the rotors using both a mechanical hydraulic system and a digital stabilization system. The digital stabilization system fine-tunes the powerful hydraulic system to keep the helicopter flying smoothly. The stabilization system can also keep the helicopter in an automatic hovering position for short periods of time.

On the Longbow Apache, three display panels provide the pilot with most navigation and flight information. These digital displays are much easier to read than traditional instrument dials. The pilot simply presses buttons on the side of the display to find the information he or she needs.


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Inside the Apache Longbow cockpit

One of the coolest things about the Apache is its sophisticated sensor equipment. The Longbow Apache detects surrounding ground forces, aircraft and buildings using a radar dome mounted to the mast. The radar dome uses millimeter radio waves that can make out the shape of anything in range. The radar signal processor compares these shapes to a database of tanks, trucks, other aircraft and equipment to identify the general class of each potential target. The computer pinpoints these targets on the pilot's and gunner's display panels.

The pilot and the gunner both use night vision sensors for night operations. The night vision sensors work on the forward-looking infrared (FLIR) system, which detects the infrared light released by heated objects. The pilot's night vision sensor is attached to a rotating turret on top of the Apache's nose. The gunner's


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night vision sensor is attached to a separate turret on the underside of the nose. The lower turret also supports a normal video camera and a telescope, which the gunner uses during the day.

The computer transmits the night vision or video picture to a smallDisplay unit in each pilot's helmet. The video display projects the image onto a monocular lens in front of the pilot's right eye. Infrared sensors in the cockpit track how the pilot positions the helmet and relay this information to the turret control system. Each pilot can aim the sensors by simply moving his or her head! Manual controls are also available, of course.

THE SENSOR ARRAY

EVASION & ARMOUR


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The Apache's first line of defense against attack is keeping out of range. As we saw earlier, the helicopter is specifically designed to fly low to the ground, hiding behind cover whenever possible. The Apache is also designed to evade enemy radar scanning.

If the pilots pick up radar signals with the onboard scanner, they can activate a radar jammer to confuse the enemy.

The Apache is also designed to evade heat-seeking missiles by reducing its infrared signature (the heat energy it releases). The Black Hole infrared suppression system dissipates the heat of the engine exhaust by mixing it with air flowing around the helicopter. The cooled exhaust then passes through a special filter, which absorbs more heat. The Longbow also has an infrared jammer, which generates infrared energy of varying frequencies to confuse heat-seeking missiles. The Apache is heavily armored on all sides. Some areas are alsosurrounded by Kevlar soft armor for extra protection. The cockpit is protected by layers of reinforced armor and bulletproof glass. According to Boeing, every part of the helicopter can survive 12.7-mm rounds, and vital engine and rotor components can withstand 23-mm fire.

The area surrounding the cockpit is designed to deform during collision, but the cockpit canopy is extremely rigid. In a crash, the deformation areas work like the crumple zones in a car -- they absorb a lot of the impact force, so the collision isn't as hard on the crew. The pilot and gunner seats are outfitted with heavy Kevlar armor, which also absorbs the force of impact. With these advanced systems, the crew has an excellent chance of surviving a crash.


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THE APACHE HELICOPTER

CONCLUSIONDept. Of Mechanical Engg, EPCET

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With the design of the apache the very concept of helicopter itself haschanged all over the world. Many countries like Russia, Germany etc. have rolled over their versions of attack helicopters. They replaced the main drawbacks of apache. Flying an Apache into battle is extremely dangerous, to be sure, but with all its weapons, armor and sensor equipment, it is a formidable opponent to almost everything else on the battlefield. It is a deadly combination of strength, agility and firepower. And hence it can be surely emphasized that the Apache is the pioneer in the attack helicopter family. Hope that APACHE becomes a part of THE INDIAN ARMY in the near future.

REFERENCE

www.howstuffworks.comwww.answers.comwww.google.comwww.wikiepedia.orgwww.helicopters.comwww.apachehelicopters.com


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