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Apache Helicopters
Apache weapons
AH-64A/D Apache upgrades
Countermeasures
Engines
Performance
Sensors
AH-64 Apache (AGM-114 Hellfire variants)
Apache weapons

A 30mm automatic Boeing M230 chain gun is located under the fuselage. It provides a rate of fire of 625 rounds a minute. The helicopter has capacity for up to 1,200 rounds of ammunition.

The AH-64D is armed with the Lockheed Martin / Boeing AGM-114D Longbow Hellfire air-to-surface missile which has a millimetre wave seeker which allows the missile to perform in full fire and forget mode. Range is 8km to 12km.

"The helicopter has capacity for up to 1,200 rounds of ammunition."The Apache can be equipped with air-to-air missiles (Stinger, AIM-9 Sidewinder, Mistral and Sidearm) and the advanced precision kill weapon system (APKWS), formerly known as Hydra, family of guided and unguided 70mm rockets. Plans to arm the Apache with the advanced precision kill weapon system (APKWS) II, a laser-guided version of the Hydra were shelved in the FY2008 budget. The _______ awarded BAE Systems a development _______ for the APKWS II in April 2006.

British Army AH mk1 helicopters are armed with the CRV7 70mm rocket system from Bristol Aerospace of Winnipeg, Manitoba.

The Longbow Apache carries the combination of armaments chosen for the particular mission. In the close support role, the helicopter carries 16 Hellfire missiles on four four-rail launchers and four air-to-air missiles.

Sensors

The AH-64D Longbow Apache is equipped with the Northrop Grumman millimetre-wave Longbow radar. The Longbow fire control radar incorporates an integrated radar frequency interferometer for passive location and identification of radar-emitting threats. An advantage of millimetre wave is that it performs under poor-visibility conditions and is less sensitive to ground clutter. The short wavelength allows a very narrow beamwidth, which is resistant to countermeasures.

Apache AH Mk1 Attack HelicopterThe Apache AH Mk1 is an attack helicopter produced by AgustaWestland under license from Boeing, for the British Army.

The Longbow Apache can effect an attack in 30 seconds. The radar dome is unmasked for a single radar scan and then remasked. The processors determine the location, speed and direction of travel of a maximum of 256 targets.

The target acquisition designation sight, TADS (AN/ASQ-170), and the pilot night vision sensor, PNVS (AN/AAQ-11), were developed by Lockheed Martin. The turret-mounted TADS provides direct-view optics, television and three-fields-of-view forward-looking infrared (FLIR) to carry out search, detection and recognition, and Litton laser rangefinder / designator. PNVS consists of a FLIR in a rotating turret located on the nose above the TADS. The image from the PNVS is displayed in the monocular eyepiece of the Honeywell integrated helmet And display sighting system, IHADSS, worn by the pilot and copilot / gunner.

Lockheed Martin has developed a new targeting and night vision system for the Apache, using second-generation long-wave infrared sensors with improved range and resolution. The new system is called Arrowhead and has a targeting FLIR with three fields of view, a dual field-of-view pilotage FLIR, a CCD TV camera, electronic zoom, target tracker and auto-boresight.

"Lockheed Martin has developed a new targeting and night vision system for the Apache."Arrowhead entered production in December 2003 and the first unit was delivered to the US Army in May 2005. The first Arrohead system was integrated to the Apache helicopter in June 2005. A total of 704 US Army Apaches were to be equipped with Arrowhead by 2011. The 500th delivery was made in 2008 and the remaining deliveries were completed as scheduled. The US Army has also placed follow-on contracts for additional Arrowhead fittings to its fleet of Apaches, increasing the total number of Arrowhead integrations for the _______.

A ______ to equip the UK AH Mk1 helicopters with Arrowhead was placed in May 2005. The first two were delivered in November 2008 and deliveries concluded in 2010.

Countermeasures

The Apache is equipped with an electronic warfare suite consisting of: AN/APR-39A(V) radar warning receiver from Northrop Grumman (formerly Litton) and Lockheed Martin; Lockheed Martin AN/APR-48A Radar Frequency Interferometer Electronic Support target acquisition system; AN/ALQ-144 infra-red countermeasures set from BAE Systems IEWS (formerly Sanders, a Lockheed Martin company); AN/AVR-2 laser warning receiver from Goodrich (formerly Hughes Danbury Optical Systems then Raytheon); AN/ALQ-136(V) radar jammer developed by ITT; and chaff dispensers.

Z-10 Attack HelicopterThe Z-10 attack helicopter was developed by the Changhe Aircraft Industries Group (CHAIG) and China Helicopter Research and Development Institute (CHRDI).

_______ Longbow Apaches were to be fitted with the ITT AN/ALQ-211 SIRCM (suite of integrated radio frequency countermeasures) suite, however the availability of funding for this project is uncertain.

UK AH mk1 Apaches are fitted with BAE Systems helicopter integrated defensive aids suite (HIDAS), also chosen by Kuwait and Greece. HIDAS, which includes the Sky Guardian 2000 radar warning receiver, entered service on the AH mk1 in July 2003.

______ AH-64D helicopters are fitted with the Elisra Seraph self-protection system, including SPS-65 missile warner and SPJ-40 radar jammer.

Dutch AH-64D helicopters are being fitted with the Northrop Grumman directional infrared countermeasures (DIRCM) pod.

 Engines

The Apache is equipped with two turboshaft engines, each providing 1,265kW. The American AH-64D has General Electric T700-GE-701 engines and the UK Apache is fitted with RTM322 engines from Rolls-Royce / Turbomeca.

 Performance

The AH-64 Apache can climb at a rate of 889m/min. The maximum and cruise speeds of the helicopter are 279km/h and 260km/h respectively. The ferry range and service ceiling of the helicopter are 1,900km and 6,400m respectively. The endurance is 3 hours 9 minutes. The helicopter weighs around 5,165kg, while the maximum take-off weight is 10,433kg.


Range 400 km - internal fuel
1,900 km - internal and external fuel

The Apache can be equipped with air-to-air missiles (Stinger, AIM-9 Sidewinder, Mistral and Sidearm) and the advanced precision kill weapon system (APKWS), formerly known as Hydra, family of guided and unguided 70mm rockets.

Engines

The Apache is equipped with two turboshaft engines, each providing 1,265kW. The American AH-64D has General Electric T700-GE-701 engines and the UK Apache is fitted with RTM322 engines from Rolls-Royce / Turbomeca.

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 article, 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.

At its core, an Apache works pretty much the same way as any other 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. (See How Airplanes Work to find out how lift is generated.)

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 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. (See How Helicopters Work for a full explanation.)

We'll learn more about the rotors and blades next.

Apache Rotors and Blades

As the main rotor 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.

The newest Apache sports twin General Electric T700-GE-701C turboshaft engines, boasting about 1,700 horsepower each. Each engine turns a drive shaft, which is connected to a simple gear box. The gear box 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.

Apache Hellfire Missiles

The Apache's chief function is to take out heavily armored ground targets, such as tanks and bunkers. To inflict this kind of damage, you need some heavy fire power, and to do it from a helicopter, you need an extremely sophisticated targeting system.

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 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.

•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.

We'll look at the Apache's rockets next.

Apache Rockets and Chain Gun

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 submunitions, small bombs that separate from the rocket in the air and fall on targets below.

The gunner engages close-range targets with an 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 swing the turret from side to side and up and down.

The automatic cannon is a chain gun design, powered by an electric motor. 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.

The M-230A1 30-mm automatic cannon on an AH-64A Apache

Apache Controls

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 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.

Inside the Apache Longbow cockpitan traditional instrument dials. The pilot simply presses buttons on the side of the display to find the information he or she needs.

We'll look at the Apache's sensor equipment next.


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. (See How Night Vision Works for more information.)

The pilot's night vision sensor is attached to a rotating turret on top of the Apache's nose. The gunner's 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 sensor array on an Apache helicopter

Apache Evasion Tactics and Armor

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 also surrounded 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.
Black Hawk and Apache Engine
AH-64 Apache helicopter

Front view of an Apache attack helicopter showing its main rotor and turbofan engines

AH-64 in flight over rough desert terrain

Front view of a AH-64D Longbow Apache variant

Longbow Apache hovering among trees

Radar mast atop the main rotor of a __________ AH-64D

Longbow armed with a heavy load of 16 Hellfire anti-tank missiles

Front view of a hovering AH-64 showing the cannon mounted under its nose
Apache helicopter
AH-64 Apache
AH-64 Apache - Military Aircraft
Specifications (AH-64A/D)
Apache Sensors
Specifications

General characteristics

Performance

Armament

Avionics



The Apache has been designed to fight and survive during the day, night, and in adverse weather throughout the world. The principal intended mission of the Apache is the destruction of high-value targets with the HELLFIRE missile, primarily hostile armor. It is also capable of employing a 30mm M230 chain gun and the Hydra 70 (2.75 inch) family of rockets that are lethal against a wide variety of targets. The Apache has a full range of aircraft survivability equipment and has the ability to withstand hits from rounds up to 23mm in critical areas. The AH-64 is air transportable in the C-5, C-141 and C-17.

The AH-64 Apache is a twin-engine, four bladed, multi-mission attack helicopter designed as a highly stable aerial weapons-delivery platform. It is designed to fight and survive during the day, night, and in adverse weather throughout the world. With a tandem-seated crew consisting of the pilot, located in the rear cockpit position and the co-pilot gunner (CPG), located in the front position, the Apache is self-deployable, highly survivable and delivers a lethal array of battlefield armaments. The Apache features a Target Acquisition Designation Sight (TADS) and a Pilot Night Vision Sensor (PNVS) which enables the crew to navigate and conduct precision attacks in day, night and adverse weather conditions.

The Apache program had the potential to evolve into four different models in service simultaneously. These models were, the AH-64A, an AH-64+ with product improvements applied, and an AH-64D Longbow Apache with glass cockpit display, advanced engines, wiring for Longbow systems, radar interferometer, and the Longbow missile system. This AH-64D standard was previously known as AH-64C. Approximately 1/3 of the Longbow fleet was planned to also be equipped with the Longbow millimeter wave fire control radar, the original AH-64D standard.

The Apache can carry up to 16 HELLFIRE (Helicopter-Launched, Laser-guided, Fire and Forget) laser guided missiles. With a range of over 8000 meters, the HELLFIRE is used primarily for the destruction of tanks, armored vehicles and other hard materiel targets. The Apache can also deliver a maximum of 76, 70mm/2.75" wrap-around fin aerial rockets (WAFAR) for use against enemy personnel, light armor vehicles and other soft-skinned targets. Rounding out the Apache's deadly punch are 1,200 rounds of ammunition for its Area Weapons System (AWS), featuring the M230 30mm Automatic Gun.

An on-board video recorder has the capability of recording up to 72 minutes of either the pilot or CPG selected video. It is an invaluable tool for damage assessment and reconnaissance. The Apache's navigation equipment consists of a doppler navigation system, and most aircraft are equipped with a GPS receiver.

The Apache has state of the art optics that provide the capability to select from three different target acquisition sensors. These sensors are:

¦Day TV - Views images during day and low light levels, black and white. ¦TADS FLIR - Views thermal images, real world and magnified, during day, night and adverse weather. ¦DVO - Views real world, full color, and magnified images during daylight and dusk conditions. AH-64 aviators use the Integrated Helmet and Display Sighting System (IHADSS). The IHADSS helmet, at the time of its development, was lighter in weight and provided improved impact protection over the then-current SPH-4 series helmet. The IHADSS was the only helmet approved for the AH-64 and has been in use for over 20 years. A unique feature of the IHADSS helmet is that it serves as a platform for a Helmet Mounted Display (HMD). The HMD provides pilotage and fire control imagery and flight symbology. In order to view the HMD imagery, the helmet/HMD must be fitted such that the exit pupil of the HMD is properly aligned with the aviator's eye each time it is donned. This makes the fit and stability of the IHADSS helmet critical considerations. Achieving a proper fit of the IHADSS helmet is complicated by its intricate system of straps and pads. A proper, customized, repeatable fit is required in order to maintain the exit pupil position and optimize the resulting full Field of View (FOV). Fitting of the IHADSS helmet typically takes several hours to complete. This fitting process must be repeated every time aviators are transferred to a new duty station, as they cannot take the IHADSS helmet with them. It is part of the AH-64 aircraft system and is unit property.

The Apache has four articulating weapons pylons, two on either side of the aircraft, on which weapons or external fuel tanks can be mounted. The aircraft has a Laser Range Finder/Designator (LRF/D). This is used to designate for the HELLFIRE missile system as well as provide range to target information for the fire control computer's calculations of ballistic solutions.

Threat identification through the FLIR system is extremely difficult. Although the AH-64 crew can easily find the heat signature of a vehicle, it may not be able to determine friend or foe. Forward looking infrared detects the difference in the emission of heat in objects. On a hot day, the ground may reflect or emit more heat than the suspected target. In this case, the environment will be "hot" and the target will be "cool". As the air cools at night, the target may lose or emit heat at a lower rate than the surrounding environment. At some point the emission of heat from both the target and the surrounding environment may be equal. This is IR crossover and makes target acquisition/detection difficult to impossible. IR crossover occurs most often when the environment is wet. This is because the water in the air creates a buffer in the emissivity of objects. This limitation is present in all systems that use FLIR for target acquisition.

Low cloud ceilings may not allow the HELLFIRE seeker enough time to lock onto its target or may cause it to break lock after acquisition. At extended ranges, the pilot may have to consider the ceiling to allow time for the seeker to steer the weapon onto the target. Pilot night vision sensor cannot detect wires or other small obstacles.

Overwater operations severely degrade navigation systems not upgraded with embedded GPS. Although fully capable of operating in marginal weather, attack helicopter capabilities are seriously degraded in conditions below a 500-foot ceiling and visibility less than 3 km. Because of the HELLFIRE missile's trajectory, ceilings below 500 feet require the attack aircraft to get too close to the intended target to avoid missile loss. Below 3 km visibility, the attack aircraft is vulnerable to enemy ADA systems. Some obscurants can prevent the laser energy from reaching the target. They can also hide the target from the incoming munitions seeker. Dust, haze, rain, snow and other particulate matter may limit visibility and affect sensors. The HELLFIRE remote designating crew may offset a maximum of 60 degrees from the gun to target line and must not position their aircraft within a +30-degree safety fan from the firing aircraft.

Powered by two General Electric gas turbine engines rated at 1890 shaft horsepower each, the Apache's maximum gross weight is 17,650 pounds which allows for a cruise airspeed of 145 miles per hour and a flight endurance of over three hours. The AH-64 can be configured with an external 230-gallon fuel tank to extend its range on attack missions, or it can be configured with up to four 230-gallon fuel tanks for ferrying/self-deployment missions. The combat radius of the AH-64 is approximately 150 kilometers. With one external 230-gallon fuel tank the radius is approximately 300 kilometers. Both radii are dependent on temperature, pressure altitude, fuel burn rate, and airspeed. The addition of up to two wing tanks can further extend range. However, this configuration is currently authorized for ferry/self-deployment flights only. The Apache can attack targets up to 150 km across the FLOT. If greater depth is required, the addition of ERFS tanks can further extend the AH-64's range with a corresponding reduction in HELLFIRE missile carrying capacity (four fewer Hellfire missiles for each ERFS tank installed).

The Apache fully exploits the vertical dimension of the battlefield. Aggressive terrain flight techniques allow the commander to rapidly place the ATKHB at the decisive place at the optimum time. Typically, the area of operations for Apache is the entire corps or divisional sector. Attack helicopters move across the battlefield at speeds in excess of 3 kilometers per minute. Although dependent on mission, enemy, terrain, troops, time available, and civilian (METT-TC) considerations, typical planning airspeeds are 100-120 knots (185-222 km/hr) during daylight, and 80-100 knots (148-185 km/hr) at night. Speeds during marginal weather are reduced with respect to prevailing conditions.