AH-64D Longbow best helicopter on the World
Longbow Helicopter
The AH-64D Longbow Apache is structurally very similar to the original Apache – AH-64A. Key improvements include a more powerful engine, improved avionics and navigation systems, and a modern digital cockpit. All AH-64Ds have received the improvements, but only 227 have been fitted with the Longbow radar.
The AH-64D Longbow Apache is the ultimate development of America’s most important attack helicopter program to date. US Army pilots have described the Longbow as a helicopter from the next generation.
Development of AH-64D
Since the earliest days of AH-64A operations there have been plans to upgrade the helicopter. In the mid-1980s, even as the first Apaches were entering service, McDonnell Douglas began studies of the Advanced/Apache Plus, which was later referred to, unofficially, as the “AH-64B.” The AH-64B would have had a revised, updated cockpit with a new fire control system, Stinger air-to-air missiles, and a redesigned Chain Gun. Aimed exclusively at the US Army, the program was abandoned before it reached the hardware stage.
With new technologies becoming available, there was now the possibility of transforming the already formidable Apache into something of even greater capability: Operational limitations with the AH-64A became apparent during Desert Storm and provided the stimulus for developing an improved attack variant.
AH-64D Armament
One of the “new” Apache’s most significant developments was the mounting of a Longbow radar above the rotor-head to provide millimeter-wave (MMW) guidance for specially developed “fire-and-forget” AGM-114L Hellfire missiles. When this was fully integrated into the helicopter’s systems, the AH-64D was renamed the Longbow Apache. Largely impervious to atmospheric interference, the mast-mounted Longbow radar system allows the AH-64D to launch all 16 AGM-114L Hellfire missiles while remaining hidden behind a tree-line. Thus, in wartime, the Longbow Apache can stay concealed while attacking targets, thereby increasing its chances of surviving retaliation from AAA or shoulder-launched SAMs.
AH-64D Radar
The AH-64D Longbow mast-mounted rotating antenna weighs some 250lb. It can scan through 360″ in searching for aerial targets: in ground attack mode it can scan for vehicle and other non-flying targets over an arc of 270″. The AN/APG-78 Longbow radar can handle up to 256 targets simultaneously, presenting them to the pilot and gunner on color multifunction displays.
Although the radar system is probably the most important change in a tactical sense, the Longbow Apache has been significantly upgraded in other areas. The AH-64D has been fitted with a totally new avionics system. Four dual-channel MIL-STD 1553B data buses combine with new processors and an uprated electrical system to greatly increase the capabilities of the AH-64D compared to the AH-64A. The cockpit of the original Apache was a confusing mass of dials and more than 1,200 switches: in the Longbow cockpit these have been replaced by a Litton Canada multi-function display, two 6in square color CRT displays from Allied Signal Aerospace, and just 200 switches.
Longbow Helicopter Equipment
Improved helmet-mounted displays, an upgraded Plessey AN/ASN-157 Doppler navigation system, and Honeywell AN/APN-209 radar altimeter have also been incorporated. In service the AH-64D Longbow will have a dual embedded GPS and inertial navigation fit plus new secure VHF/FM radios. The helicopter’s improved navigation suite gives it near all-weather capability – the original Apache-A was more accurately described as having adverse-weather capability. The larger volume of avionics needing to be crammed into the Longbow has forced the designers to expand the size of the Apache’s cheek fairings, which have become known as EFABs (Enhanced Forward Avionics Bays).
The fluid nature of the battlefield has seen communication between friendly forces play an increasingly important role. Incorporating a data transfer module (DTM), the AH-64D is able to talk not only to other AH-64Ds and OH-58Ds, but also to USAF C3I assets such as the Rivet-Joint RC-135 and the J-STARS E-8. Target information can be supplied to the Longbow Apache crew on a secure frequency, allowing them to be directed safely into an assigned “killing zone.” Once the attack has begun, the Longbow radar can catalog targets, designating those that are deemed to be the most threatening.
Apache Longbow Engines
The Apache’s current General Electric T700-GE-701 turboshafts are to be completely replaced by uprated 1,723shp (1,285kW) T700-GE-701C engines. The more powerful 701C has already been standard on existing AH-64As (from the 604th production aircraft, delivered in 1990, onwards) and has proved to deliver a marked increase in performance.
AH-64D Upgrades and Service
The US Defense Acquisition Board authorized a 51-month AH-64D development program in August 1990. This was later extended to 70 months to incorporate integration of the AGM-114L Hellfire missile. Full-scale production of 232 Longbows was authorized on October 13, 1995, with the complete US Army AH-64D contract also calling for 13,311 AGM-114L missiles. The first AH-64Ds were delivered in March 1997, with the first front line unit becoming operational in July 1998.
Echoing the reaction to the original Apache in the late 1970s, the AH-64D was criticized by many observers as being too complex, too expensive, and potentially unreliable. But the Longbow’s capability was validated spectacularly in a series of field tests carried out between January 30 and February 9, 1995, at China Lake. In the tests, a joint team of AH-64As and AH-64Ds undertook gunnery trials involving some of the most complex exercise scenarios ever devised. The test results were staggering. The AH-64Ds achieved 300 confirmed enemy armor kills, as compared to the AH-64As, which notched up just 75. Four AH-64Ds were deemed to have been shot down, as opposed to 28 AH-64As. One test official slated, “In all my years of testing, I have never seen a test system which could so dominate the system it is intended to replace.”
AH-64D Specification
Name: | AH-64D Longbow Apache |
Role: | Attack Helicopter |
First Flight: | 1975 | Introduction: | 1986 |
Primary User: | United States and Israel Air Force |
Service: | In service |
Crew: | 2 (pilot and gunner) |
Capacity: | 2 (crew) |
Length: | 17.73 m (58 ft) | Rotor Diameter: | 14.60 m (48 ft 5 in) |
Height: | 3.87 m (12 ft 6 in) | Weight: | 5,165 kg (11,400 lb) |
Loaded Weight: | 8,000 kg (17,700 lb) | Max. Weight: | 10,500 kg (23,050 lb) |
Powerplant: | 2 × General Electric T700-GE-701D | Power: | 1,300 kW (1,690 shp) |
Fuel Ecnomy: | 1.38 km/l (3.25 NM/gallon) | Tank Capacity: | 1.420 l (375 gallon) |
Max. Speed: | 365 km/h (197 knots, 230 mph) | Range: | 476 km (257 nmi, 295 mi) |
Rate Of Climb: | 12.7 m/s (2,520 ft/min) |
Service Ceiling: | 6,100 m (20,000 ft) |
Number Built: | 1,200 (All variants) |
Unit Cost: | 55-65 million USD |
Boeing Official Page - http://www.boeing.com/
AH-64D Video
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