AH-64 Apache :Specification

MANUFACTURER: McDonnell Douglas Helicopters
CREW: 2 (pilot, copilot/gunner)
ENGINES: 2 General Electric T700-GE-701 or -701C turboshaft
Max power: 1,695 shp (-701) or 1,890 shp (-701C) each
Internal fuel capacity:376 US gal (1,422 liters)

WEIGHTS:
Empty: 10,760 Ib (4,881 kg)
Primary mission gross weight:
14,445 Ib (6,553 kg) with 3,350 Ib (1,520 kg) weapons load and 2,500 Ib (1,134 kg) of fuel 17,650 Ib (8,006kg)
Ferry mission: 21,000 Ib (9,525 kg)

DIMENSIONS:
Rotor diam: 48 ft (14.63 m)
Length: 48 ft 2 in (14.68 m)
Height top of rotor: 12 ft 7 in (3.84 m)
Top of air data sensor: 15 ft 31/? in (4.66 m)
Disc area :1,809.5 ft2 (168.1 m2)

PERFORMANCE:
Army Hot day = 95° F/(35° C at
4,000 ft/1,220m
Speed max clean: 164 kts (189 mph;304km/h)Army Hot day: 147-155kts (169-178 mph;
272-287 km/h)Euro theater, 2,000 ft
(610 m) at 70° F (21°C): 148-153 kts (170-176 mph; 274-284km/h)
Econ cruise sea level, standard day:128 kts (147 mph; 237km/h)
Army Hot day: 119 kts(137 mph; 221 km/h)
Rate of climb max standard day: 3,200 ft/ min (975 m/min)
Army Hot day: 2,750 ft/min (783 m/min)
Max, vertical standard day: 2,460 ft/ min (750 m/min)
Army Hot day: 1,450 ft/ min (442 m/min)
Ceiling standard day:2 engines: 21,000 ft(6,400 m)1 engine: 10,800 ft (3,292m)Army Hot day2 engines: 10,300 ft(3,139 m)1 engine: 6,400 ft (1,951m)
Hovering ceiling in ground effect: 14,445Ib (6,553 kg)
Standard day: 15,000 ft(4,572 m)
Army Hot day: 10,200 ft(3,109 m)
hovering ceiling out of ground effect,
14,445 Ib (6,553 kg) standard day: 11,500ft (3,505 m)
Army Hot day: 7,000 ft(2,134m)
Range internal fuel: 260 nm
(300 mi; 482 km)
Ferry: 918 nm (1,057 mi;
1,701 km)armament 1 M230 Chain Gun 30-mm cannon in belly turret with 1,200 rounds 4 wing pylons for up to 16 Hellfire antitank missiles or 76 2.75-in (70-mm) rockets in 4 pods and 4 FIM-92 Stinger airto-
air missiles.

AH-64 Apache :Overview

The AH-64 Apache is the US Army's principal gunship/antitank helicopter. It was the winner in the 1973-76 competition for an Advanced Attack Helicopter (AAH), beating out the Bell YAH-63 entry. The AH-64 Apache is intended primarily for the antitank role, with an all-weather/night operating capability. It is relatively fast and maneuverable, carries a large antiarmor weapons load, has reduced radar and Infrared (IR) signatures, is damageresistant against most small and medium antiaircraft artillery, and is crashworthy.

AH-64 Apache :Characteristics

The four-blade main rotor assembly consists of a hollow mast with an inertiawelded nickel-steel driveshaft. Each blade has five stainless-steel spars, steel leading edge, stainless-steel skin, and composite trailing edge. The blade design features a high-lift airfoil section and swept tips; the 20° sweep at the tips delays compressibility and improves the stability of both advancing and retreating blades.

The blades are linked to the hub arms with 22-ply-laminate strap packs. Two lead-lag dampers are fitted to each hub arm, and the flapping hinge is offset to 4% of blade radius to augment control power. The blades can be folded for transport by large cargo aircraft.

The antitorque rotor has two two-blade teetering rotors with a relatively low tip speed, which reduces tail rotor noise, and a 4,500-hour fatigue life. The titanium fork assembly carries one set of blades in elastomeric bearings above the plane of the other and at a 60°/120° angle. The tailplane had originally been mounted at the top of the tail. After tests, the broad, all-moving surface was relocated to near the base of the pylon. It adjusts automatically to provide a level attitude during Nap of the Earth (NOE) flight.

Primary flight control is by hydraulic actuation; a Sperry Fly-by-Wire (FEW) is provided as a backup. Stabilization is by the Sperry Digital Automatic Stabilization Equipment (DASE). Manufacturer McDonnell Douglas Helicopters claims that the AH-64 Apache can move laterally and to the rear at speeds up to 45 kts (52 mph; 83 km/h). Maximum load factors are +3.5 g/—0.5 g; the positive load factor is reduced to 2.4 g with a 3,350-lb (1,520- kg) weapons load.

The two turboshaft engines are shoulder-mounted on the fuselage behind the main rotor mast. Each engine is fitted with a "black hole" passive IR exhaust suppressor.

The fuselage is designed to be crashworthy in vertical crashes of up to 42-ft/ sec descent; the crew compartment is further protected by progressive deformation of the rest of the airframe, which absorbs additional energy. The entire airframe is designed to be invulnerable to 12.7-mm rounds. In addition, most vital components can sustain hits from 23-mm rounds and continue flying to a safe landing. The pilot and copilot/gunner sit in tandem, Kevlar-armored seats surrounded by boron armor and under a heavily framed canopy. The canopy frame is designed to act as a roll cage, and the glazing between the crew members is impact-resistant; the glazing is not ballistically tolerant. The pilot is in the rear seat, which is 19 in (480 mm) above the copilot/gunner's. The front seat has a full set of flight controls that are typically stowed under the front sight.

The landing gear is fixed with the main, trailing-arm struts below the pilot's position and the tail gear extending beyond the tail rotor pylon. Detachable stub wings are fitted to the fuselage below the main rotor mast; each wing has two weapons pylons.

The core of the avionics fit is the Martin Marietta Target Acquisition and Designation Sight/Pilot's Night Vision Sensor (TADS/PNVS) linked to the Honeywell Integrated Helmet and Display Sight System (IHADSS) worn by both crew members. The turrets for the TADS and PNVS systems are fitted in the nose of the Apache. The upper PNVS turret contains a Forward-Looking Infrared (FLIR) sensor directly linked to the IHADSS and traverses with the user's head movements. Azimuth range is +/-900; elevation is +20°/-45°. The lower TADS turret is divided vertically; the left half has direct vision optics with two fields of view (4° and 18°) above a daylight TV with 0.9° and 4° fields of view.

The right half has a FLIR sensor. TADS is also fitted with a laser spot tracker and laser designator. Azimuth coverage is +/-1200, elevation is +30°/-60°. TADS imagery is relayed to the copilot/gunner through an optical relay "tube" that resembles a small console; it has both Head- Down and Head-Up Displays (HDD/ HUD).

The three principal weapons systems on the AH-64 Apache are the McDonnell Douglas Helicopters M230 30-mm Chain Gun, Rockwell AGM-114 Hellfire laser-guided antitank missiles, and Hydra 2.75-in (70- mm) rocket pods. The Chain Gun is fitted in a turret below the cockpit; turret traverse is +/ —100°, elevation is + 110/—60°. Ammunition is fed from a 1,200-round pallet fitted under the main rotor assembly; operational experience has shown that a 380-round ammunition load is best. The stub pylons can carry up to 16 Hellfire missiles, although a load of eight is more typical. As an alternative load, up to four 19-rocket Hydra pods can be carried.

To improve its self-defense capabilities, the AH-64 Apache was tested in November 1987 with Loral Aeroneutronic AIM-9 Sidewinder Air-to-Air Missiles (AAM) fitted on stub wingtip rails. The usual AAM fit, however, is the Air-to-Air Stinger (ATAS) adaptation of the General Dynamics FIM-92 Stinger shoulder-fired surface-toair missile. Shorts (UK) Starstreak and Matra Mistral air-to-air and AGM-122 Sidearm antiradar missiles are also compatible.

AH-64 Apache :Development

The Apache's initial operational capability was in 1985. Its first flight was on September 30, 1975, and its first production rollout was in January 1984; the 500th production aircraft was rolled out on September 15, 1989. The first squadron of Apache's stationed in Europe arrived in August 1987 as part of REFORGER '87. A total of 975 AH-64A Apaches had been planned for procurement through FY1992, equipping 27 attack helicopter battalions. With the defense drawdowns following the collapse of the Soviet Union, the figure was again reduced under former Defense Secretary Cheney.

Since its service entry in 1985, the AH-64 Apache has been the most advanced combat helicopter in service as well as plagued with reliability shortcomings in several key areas. Several studies conducted by the General Accounting Office (GAO) found many faults with the Apache, both mechanical and with its electronics.

Several countries have purchased the AH-64 Apache: Bahrain, Egypt, Greece, Israel, Kuwait, Saudi Arabia, and the United Arab Emirates.

AH-64 Apache :Variants

AH-64 D Apache Longbow: The advanced model, the AH-64 D 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-64 Ds 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-64 D Apache Longbows", as the radome is removable and interchangeable between aircraft. AH-64 Ds 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. 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-64 A Apache are retained.

AH-64 Apache :Combat Experience

In December 1989, 11 Apache's flew 200 hours of missions in support of the US military operation Just Cause to remove Panamanian General Noriega from power; 66% of the flying time was at night. According to the US Army, three AH-64's were damaged by ground fire and one aircraft took 32 7.62-mm hits, but they were back in service within 24 hours. The Army reported that Hellfire missiles used against fixed targets, including General Noriega's headquarters, were very accurate and effective.

In August 1990, Apaches from the 101st Airborne Division (Air Assault) were sent to Saudi Arabia as part of the US response to the Iraqi invasion and annexation of Kuwait. Accounts of their degree of readiness varied from 70% to 90%.

Eight Apaches were used to attack early-warning radar sites in western Iraq on a round-trip of 950 nm (1,094 mi; 1,759 km) that opened Operation Desert Storm's air war. The mission, which cleared an attack lane for precision strikes, achieved complete surprise and within two minutes had scored 15 hits with Hellfire missiles.

Additional reports during Desert Storm suggest that the AH-64 Apache performed very well, whether alone or when flown in concert with the A-10. When the ground war was launched, Apaches led the 101st Airborne's airlift into Iraq. During the ground assaults against Iraq's Republican Guard formations, some AH-64's hit and destroyed several tanks with a single load of eight Hellfires. Overall, Apache's fired 2,876 Hellfires during Desert Storm. The 4th Battalion of the 229th Aviation Brigade was credited with 50 tanks in a single battle.

Serviceability reportedly remained high, and the AH-64 Apache ended the campaign with an enhanced reputation.