Monday, February 19, 2007

Apache

AH-64 Apache
Type Attack helicopter
Manufacturer Hughes, McDonnell Douglas, Boeing IDS
Maiden flight 30 September 1975
Status Active service
Primary users United States Army
Israel
Produced 1984-1996
Number built 1,048[1]
Unit cost US$18 million (1984)[1]
Variants Westland WAH-64 Apache


History

The United States Army issued a request for proposals (RFP) in 1972 for an Advanced Attack Helicopter (AAH). From an initial list of 5 manufacturers, Boeing-Vertol, Bell, Hughes, Lockheed, and Sikorsky, the finalists selected were Hughes Aircraft's Toolco Aircraft Division (later Hughes Helicopters) and Bell. Hughes' Model 77/YAH-64 was selected over Bell's Model 409/YAH-63 in 1976. First flight of a development prototype occurred on September 30, 1975 but it was not until 1982 that a production contract was signed. In 1983 the first production helicopter was rolled out at Hughes Helicopter's facility at Mesa, Arizona. In 1984 Hughes Helicopters was purchased by McDonnell Douglas for $500 million. Hughes later became part of The Boeing Company with the merger of Boeing and McDonnell Douglas in August 1997.

Features

The AH-64 is a two-seat attack helicopter powered by two General Electric T700 turboshaft engines, with high-mounted exhausts on either side of the rotor shaft. The crew sit in tandem, with the pilot sitting behind and above the gunner. The crew compartment is armoured against 20mm gunfire. The helicopter is armed with a 30mm M230 chain gun which is slaved to the gunner's helmet-mounted gunsight. The AH-64 carries a range of external stores on its stub-wing pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles Hydra 70 general-purpose unguided 70mm rockets, and AIM-92 Stinger anti-aircraft missiles for defence. In case of emergency the pylons also have mounting points for personnel transfer. [1]

Royal Netherlands Air Force AH-64D at the Farnborough Air Show, 2006.
Royal Netherlands Air Force AH-64D at the Farnborough Air Show, 2006.

Two major models of AH-64 Apache are in service in the US Army; AH-64A (USAR and ARNG) and AH-64D (Active). An AH-64B variant was designed for naval operation (Marine Corps), but never manufactured.[citation needed] As of 2007 the Marine Corps still uses the AH-1 Cobra. When development of the D model started, the corresponding radarless version initially had the designation AH-64C. However, since 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, a decision was made to not distinguish between the two versions, irrespective of the presence or absence of the radar. A number of other models have been derived from both AH-64A and AH-64D for export. The British-built Westland WAH-64 (assembled from kits purchased from Boeing) is based on the AH-64D with several different systems, including newer engines.

Built to endure front-line environments, it can operate during the day or night and in adverse weather using the integrated helmet and display sight system. The Apache is also equipped with some of the latest avionics and electronics, such as the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), Black Hole passive infrared countermeasures, nap-of-the-earth (sic) navigation, and GPS.

Variants

AH-64D
Apache Longbow at the ILA airshow 2006
Apache Longbow at the ILA airshow 2006

The advanced model, the AH-64D Apache Longbow, is equipped with an improved sensor suite and weapon systems. The key improvement over the A-variant is the AN/APG-78 Longbow dome installed over the main rotor which houses a millimeter-wave Fire Control Radar (FCR) target acquisition system. The elevated position of the radome allows detection and (arcing) missile engagement of targets even when the helicopter itself is concealed by an obstacle (e.g. terrain, trees or buildings). Further, a radio modem integrated with the sensor suite allows a D-variant Apache to share targeting data with other AH-64Ds that do not have a line-of-sight to the target. In this manner a group of Apaches can engage multiple targets but only reveal the radome of one D-variant Apache. Apaches that include all of the improvements of the Longbow Apache, with the exception of the Fire Control Radar are still designated as "AH-64D Apache Longbows", as the radome is removable and interchangeable between aircraft. AH-64Ds are currently flying in Iraq and Afghanistan without the Fire Control Radar as there are simply no armored threats for coalition forces to deal with.[citation needed]

Also, the aircraft was updated with T700-GE-701C engines, and a fully-integrated cockpit. The fusaelage of the aircraft was expanded to accommodate new systems. In addition, the aircraft receives improved survivability, communications, and navigation capabilities. Most existing capabilities of the AH-64A Apache are retained.


Specifications (AH-64A)

Data from Jane's Air Forces[1]

General characteristics

  • Crew: 2: pilot, CPG (co-pilot/gunner)
  • Length: 58.17 ft (17.73 m)
  • Rotor diameter: 48 ft 0 in (14.63 m)
  • Height: 12.7 ft (3.87 m)
  • Disc area: 1,809.5 ft² (168.11 m²)
  • Empty weight: 11,387 lb (5,165 kg)
  • Loaded weight: 18,000 lb (8,000 kg)
  • Max takeoff weight: 21,000 lb (9,500 kg)
  • Powerplant: 2× General Electric T700 1,690 shp and later upgraded to T701 1,890 shp (1988-1990) and furthur upgraded to T701C (1991- today) turboshafts, (1,260 kW) each

Performance

Armament



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