The Boeing AH-64 Apache is an American twin-turboshaft attack helicopter with a tailwheel-type landing gear arrangement and a tandem cockpit for a crew of two. It features a nose-mounted sensor suite for target acquisition and night vision systems. It is armed with a 30 mm M230 chain gun carried between the main landing gear, under the aircraft’s forward fuselage, and four hardpoints mounted on stub-wing pylons for carrying armament and stores, typically a mixture of AGM-114 Hellfire missiles and Hydra 70 rocket pods. The AH-64 has significant systems redundancy to improve combat survivability.
The Apache began as the Model 77 developed by Hughes Helicopters for the United States Army’s Advanced Attack Helicopter program to replace the AH-1 Cobra. The prototype YAH-64 was first flown on 30 September 1975. The U.S. Army selected the YAH-64 over the Bell YAH-63 in 1976, and later approved full production in 1982. After purchasing Hughes Helicopters in 1984, McDonnell Douglas continued AH-64 production and development. The helicopter was introduced to U.S. Army service in April 1986. The advanced AH-64D Apache Longbow was delivered to the Army in March 1997. Production has been continued by Boeing Defense, Space & Security, with over 2,400 AH-64s being produced by 2020.
The U.S. Army is the primary operator of the AH-64. It has also become the primary attack helicopter of multiple nations, including Greece, Japan, Israel, the Netherlands, Singapore, and the United Arab Emirates. It has been built under license in the United Kingdom as the AgustaWestland Apache. American AH-64s have served in conflicts in Panama, the Persian Gulf, Kosovo, Afghanistan, and Iraq. Israel used the Apache in its military conflicts in Lebanon and the Gaza Strip. British and Dutch Apaches have seen deployments in wars in Afghanistan and Iraq.
Design
The AH-64 Apache has a four-blade main rotor and a four-blade tail rotor. The crew sits in tandem, with the pilot sitting behind and above the co-pilot/gunner. Both crew members are capable of flying the aircraft and performing methods of weapon engagements independently. The AH-64 is powered by two General Electric T700 turboshaft engines with high-mounted exhausts on either side of the fuselage. Various models of engines have been used on the Apache; those in British service use engines from Rolls-Royce. In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at 1,500 kW for AH-64Ds.
The crew compartment has shielding between the cockpits, such that at least one crew member can survive hits. The compartment and the rotor blades are designed to sustain a hit from 23 mm rounds.
The airframe includes some1,100 kg of protection and has a self-sealing fuel system to protect against ballistic projectiles. The aircraft was designed to meet the crashworthiness requirements of MIL-STD-1290, which specifies minimum requirement for crash impact energy attenuation to minimize crew injuries and fatalities. This was achieved through incorporation of increased structural strength, crashworthy landing gear, seats and fuel system.
Avionics and targeting
One of the revolutionary features of the Apache was its helmet-mounted display, the Integrated Helmet and Display Sighting System (IHADSS) among its capabilities, either the pilot or gunner can slave the helicopter’s 30 mm automatic M230 Chain Gun to their helmet, making the gun track head movements to point where they look. The M230E1 can be alternatively fixed to a locked forward-firing position or controlled via the Target Acquisition and Designation System (TADS). On more modern AH-64s, the TADS/PNVS has been replaced by Lockheed Martin’s Arrowhead (MTADS) targeting system.
U.S. Army engagement training is performed under the Aerial Weapons Scoring System Integration with Longbow Apache Tactical Engagement Simulation System (AWSS-LBA TESS), using live 30 mm and rocket ammunition as well as simulated Hellfire missiles. The Smart Onboard Data Interface Module (SMODIM) transmits Apache data to an AWSS ground station for gunnery evaluation. The AH-64’s standard of performance for aerial gunnery is to achieve at least 1 hit for every 30 shots fired at a wheeled vehicle at a range of 800–1,200 m.
The AH-64 was designed to perform in front-line environments and to operate at night or day and during adverse weather conditions. Various sensors and onboard avionics allow the Apache to perform in these conditions; such systems include the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), passive infrared countermeasures, GPS, and the IHADSS. Longbow-equipped Apaches can locate up to 256 targets simultaneously within 50 km. In August 2012, 24 U.S. Army AH-64Ds were equipped with the Ground Fire Acquisition System (GFAS), which detects and targets ground-based weapons fire sources in all-light conditions and with a 120° visual field. The GFAS consists of two sensor pods working with the AH-64’s other sensors, and a thermographic camera that precisely locates muzzle flashes.
In 2014, it was announced that new targeting and surveillance sensors were under development to provide high-resolution color imagery to crews, replacing older low definition black-and-white imaging systems. Lockheed received the first contract in January 2016, upgrading the Arrowhead turret to provide higher-resolution color imaging with longer ranges and a wider field of view. In 2014, the U.S. Army was adapting its Apaches for increased maritime performance as part of the Pentagon’s rebalance to the Pacific. Additional avionics and sensor improvements include an extended-range radar capable of detecting small ships in littoral environments, software adaptions to handle maritime targets, and adding Link 16 data-links for better communications with friendly assets.
Variants
AH-64A
The AH-64A is the original production attack helicopter. The crew sit in tandem in an armored compartment. It is powered by two GE T700 turboshaft engines. The A-model was equipped with the −701 engine version until 1990 when the engines were switched to the more powerful −701C version.
U.S. Army AH-64As are being converted to AH-64Ds. The service’s last AH-64A was taken out of service in July 2012 before conversion at Boeing’s facility in Mesa, Arizona.
AH-64B
In 1991, after Operation Desert Storm, the AH-64B was a proposed upgrade to 254 AH-64As. The upgrade would have included new rotor blades, a Global Positioning System (GPS), improved navigation systems, and new radios.
AH-64C
The C upgrade would include all changes to be included in the Longbow except for mast-mounted radar and newer −700C engine versions. However, the C designation was dropped after 1993. With AH-64As receiving the newer engine from 1990, the only difference between the C model and the radar-equipped D model was the radar, which could be moved from one aircraft to another; thus the decision was made to simply designate both versions “AH-64D”.
AH-64D
The AH-64D Apache Longbow is equipped with a glass cockpit and advanced sensors, the most noticeable of which being the AN/APG-78 Longbow millimeter-wave fire-control radar (FCR) target
acquisition system and the Radar Frequency Interferometer (RFI), housed in a dome located above the main rotor.[m The radome’s raised position enables target detection while the helicopter is behind obstacles. The AN/APG-78 is capable of simultaneously tracking up to 128 targets and engaging up to 16 at once; an attack can be initiated within 30 seconds. A radio modem integrated with the sensor suite allows data to be shared with ground units and other Apaches, allowing them to fire on targets detected by a single helicopter.
AH-64E
Formerly known as AH-64D Block III, in 2012, it was redesignated as AH-64E Guardian to represent its increased capabilities. The AH-64E features improved digital connectivity, the Joint Tactical Information Distribution System, more powerful T700-GE-701D engines with upgraded face gear transmission to accommodate more power, the capability to control unmanned aerial vehicles (UAVs), full IFR capability, and improved landing gear. New composite rotor blades, which successfully completed testing in 2004, increase cruise speed, climb rate, and payload capacity.
AH-64F
In 2014, Boeing conceptualized an Apache upgrade prior to the introduction of the U.S. Army’s anticipated attack version of the Future Vertical Lift (FVL) aircraft, forecast to replace the Apache by 2040. The conceptual AH-64F would have greater speed via a new 3,000 shp turboshaft engine from the Improved Turbine Engine Program, retractable landing gear, stub wings to offload lift from the main rotor during the cruise, and a tail rotor that can articulate 90 degrees to provide forward thrust.
Compound Apache
In October 2018, Boeing began testing the AH-64E Block 2 Compound, a compound helicopter design that added a larger fixed-wing and a pusher propeller to the Apache airframe to provide additional lift and thrust, respectively. In addition, the engine exhaust was redirected downwards. Collectively, the modifications were anticipated to improve speed to 343 km/h, range to 850 km, payload to 2,700 kg, and fuel economy.
Sea Apache
During the 1980s naval versions of the AH-64A for the United States Marine Corps and Navy were examined. Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons.
Specifications
Crew: 2 (pilot, and co-pilot/gunner)
Length: 17.73 m
Fuselage length: 15.06 m
Height: 3.87 m
Empty weight: 5,165 kg
Gross weight: 8,006 kg
Max takeoff weight: 10,433 kg
Powerplant: 2 × General Electric T700-GE-701 turboshaft engines.
Main rotor diameter: 14.63 m
Main rotor area: 1,908.5 sq ft (177.31 m2) 4-bladed main-rotor and 4-bladed tail-rotor in non-orthogonal alignment
Blade section: root: HH-02
tip: NACA 64A006
Performance
Maximum speed: 293 km/h
Cruise speed:265 km/h
Never exceed speed: 365 km/h
Range:476 km with Longbow radar mast
Combat range:480 km
Ferry range:1,896 km
Service ceiling:6,100 m
Disk loading: 48 kg/m2
Power/mass: 0.30 kW/kg
Armament
Guns: 1× 30 mm (1.18 in) M230 Chain Gun with 1,200 rounds as part of the Area Weapon Subsystem
Hardpoints: Four pylon stations on the stub wings. Longbows also have a station on each wingtip for an AIM-92 Stinger twin missile pack.
Rockets: Hydra 70 70 mm, CRV7 70 mm, and APKWS 70 mm air-to-ground rockets
Missiles: Typically AGM-114 Hellfire variants; AIM-92 Stinger and Spike missiles may also be carried.
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