Bell AH-1Z Viper

https://en.wikipedia.org/wiki/Bell_AH-1Z_Viper

The Bell AH-1Z Viper is an American twin-engine attack helicopter, based on the
AH-1W SuperCobra, that was developed for the United States Marine Corps as part
of the H-1 upgrade program. The AH-1Z features a four-blade, bearingless,
composite main rotor system, uprated transmission, and a new target sighting
system. The AH-1Z, one of the latest members of the prolific Huey family, is
also called "Zulu Cobra", based on the military phonetic alphabet pronunciation
of its variant letter.

Aspects of the AH-1Z date back to the Bell 249 in 1979, which was basically an
AH-1S equipped with the four-blade main rotor system from the Bell 412. This
helicopter demonstrated Bell's Cobra II design at the Farnborough Airshow in
1980. The Cobra II was to be equipped with Hellfire missiles, a new targeting
system and improved engines. Later came the Cobra 2000 proposal which included
General Electric T700 engines and a four-blade rotor. This design drew interest
from the US Marine Corps, but funding was not available. In 1993, Bell proposed
an AH-1W-based version for the UK's new attack helicopter program. The
derivative design, named CobraVenom, featured a modern digital cockpit and could
carry TOWs, Hellfire or Brimstone missiles. The CobraVenom design was altered in
1995 by changing to a four-blade rotor system. The design lost to the AH-64D
later that year however.

In 1996, the USMC launched the H-1 upgrade program by signing a contract with
Bell Helicopter for upgrading 180 AH-1Ws into AH-1Zs and upgrading 100 UH-1Ns
into UH-1Ys. The H-1 program created completely modernized attack and utility
helicopters with considerable design commonality to reduce operating costs. The
AH-1Z and UH-1Y share a common tailboom, engines, rotor system, drivetrain,
avionics architecture, software, controls and displays for over 84% identical
components.

Bell participated in a joint Bell-Government integrated test team during the
engineering manufacturing development (EMD) phase of the H-1 program. The AH-1Z
program progressed slowly from 1996 to 2003 largely as a research and
development operation. The existing two-blade semi-rigid, teetering rotor system
is being replaced with a four-blade, hingeless, bearingless rotor system. The
four-blade configuration provides improvements in flight characteristics
including increased flight envelope, maximum speed, vertical rate of climb,
payload and reduced rotor vibration level.

The AH-1Z's new bearingless, hingeless rotor system has 75% fewer parts than
that of four-bladed articulated systems. The blades are made of composites,
which have an increased ballistic survivability, and there is a semiautomatic
folding system for storage aboard amphibious assault ships. Its two redesigned
wing stubs are longer, with each adding a wingtip station for a missile such as
the AIM-9 Sidewinder. Each wing has two other stations for 2.75-inch (70 mm)
Hydra 70 rocket pods, or AGM-114 Hellfire quad missile launchers. The AN/APG-78
Longbow fire control radar can also be mounted on a wingtip station.


Role
Attack helicopter

National origin
United States

Manufacturer
Bell Helicopter

First flight
8 December 2000

Introduction
30 September 2010

Status
In service

Primary user
United States Marine Corps

Produced
2000–present

Number built
52

Unit cost

US$27 million
US$31 million (new built)


Developed from
Bell AH-1 SuperCobra

The AH-1Z completed sea-trial flight testing in May 2005. On 15 October 2005,
the USMC, through the Naval Air Systems Command, accepted delivery of the first
AH-1Z production helicopter to enter the fleet. The AH-1Z and UH-1Y completed
their developmental testing in early 2006. During the first quarter of 2006 the
aircraft were transferred to the Operational Test Unit at the NAS Patuxent
River, where they began operational evaluation (OPEVAL) testing.

In February 2008, the AH-1Z and UH-1Y began the second and final portion of
OPEVAL testing. AH-1Z testing was stopped in 2008 due to issues with its
targeting systems. The AH-1Z was later declared combat-ready on 30 September
2010.

Specifications (AH-1Z)

General characteristics
Crew: two: pilot, co-pilot/gunner (CPG)
Capacity: 6,661 lb (3,021 kg)
Length: 58 ft 3 in (17.8 m)
Rotor diameter: 48 ft (14.6 m)
Height: 14 ft 4 in (4.37 m)
Disc area: 1,808 ft² (168.0 m²)
Empty weight: 12,300 lb (5,580 kg)
Useful load: 5,764 lb (2,620 kg)
Max. takeoff weight: 18,500 lb (8,390 kg)
Rotor systems: 4 blades on main rotor, 4 blades on tail rotor
Powerplant: 2 × General Electric T700-GE-401C turboshaft, 1,800 shp (1,340 kW)
each

Performance
Never exceed speed: 222 knots (255 mph, 411 km/h) in a dive
Cruise speed: 160 kt (184 mph, 296 km/h)
Range: 370 nmi (426 mi, 685 km)
Combat radius: 125 nmi (144 mi, 231 km) with 2,500 lb (1,130 kg) payload
Service ceiling: 20,000+ ft (6,000+ m)
Rate of climb: 2,790 ft/min (14.2 m/s)

Armament

Guns: 1 × 20 mm (0.787 in) M197 3-barreled Gatling cannon in the A/A49E-7 turret
(750 round ammo capacity)
Hardpoints: Up to 6 pylon stations on stub wing
Rockets: 2.75 in (70 mm) Hydra 70 or APKWS II rockets – Mounted in LAU-68C/A (7
shot) or LAU-61D/A (19 shot) launchers (up to 76 unguided or 28 guided rockets
total)
Missiles:
AIM-9 Sidewinder air-to-air missiles – 1 mounted on each wing tip station (total
of 2)
AGM-114 Hellfire air-to-surface missiles – Up to 16 missiles mounted in four
4-round M272 missile launchers, two on each wing




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