Bell AH-1Z Viper

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For an overview of the whole Huey family of aircraft, see Bell Huey.
AH-1Z Viper
AH-1Z HMLA-303 in flight 2008.jpg
An AH-1Z from HMLAT-303 at Camp Pendleton
Role Attack helicopter
National origin United States
Manufacturer Bell Helicopter
First flight 8 December 2000
Introduction September 2010
Status In service, in production
Primary user United States Marine Corps
Number built 28
Unit cost
US$27 million[1]
US$31 million (new built)[2]
Developed from Bell AH-1 SuperCobra

The Bell AH-1Z Viper[3] is a twin-engine attack helicopter based on the AH-1W SuperCobra, that was developed for the United States Marine Corps. The AH-1Z features a four-blade, bearingless, composite main rotor system, uprated transmission, and a new target sighting system.[4] The AH-1Z is part of the H-1 upgrade program. It is also called "Zulu Cobra" in reference to its variant letter.

Development[edit]

Background[edit]

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.[5]

H-1 upgrade program[edit]

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.[5][6] 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 tail boom, engines, rotor system, drive train, avionics architecture, software, controls and displays for over 84% identical components.[7]

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.[5] 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.[8]

The AH-1Z first flew on 8 December 2000.[9] Bell delivered three prototype aircraft to the United States Navy's Naval Air Systems Command (NAVAIR) at Naval Air Station Patuxent River in July 2002, for the flight test phase of the program. Low-rate initial production began in October 2003,[5] with deliveries to run through 2018.[10] In late 2006 NAVAIR awarded a contract to Meggitt Defense Systems to develop a new linkless 20 mm ammunition handling system to improve on the gun feed reliability of the existing linked feed system. These systems are now being retrofitted into the AH-1W and AH-1Z fleets with good results during combat in Afghanistan.[citation needed]

In February 2008, the U.S. Navy adjusted the contract so the last 40 AH-1Zs are built as new airframes instead of the previously planned rebuild of AH-1Ws.[11] In September 2008, the Navy requested an additional 46 airframes for the Marine Corps, bringing the total number ordered to 226.[12] In 2010, the Marine Corps planned to order 189 AH-1Zs with 58 of them being new airframes,[13] with deliveries to continue until 2019.[14] On 10 December 2010, the Department of the Navy approved the AH-1Z for full-rate production.[15][16]

Design[edit]

An AH-1Z at an air show displaying four-blade rotors and longer stub wings.

The AH-1Z incorporates new rotor technology with upgraded military avionics, weapons systems, and electro-optical sensors in an integrated weapons platform. It has improved survivability and can find targets at longer ranges and attack them with precision weapons.[7]

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.[7] Its two redesigned wing stubs are longer, with each adding a wing-tip 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 Longbow radar can also be mounted on a wing tip station.[5]

AH-1Z pilots wear helmet mounted displays.

The Z-model's integrated avionics system (IAS) has been developed by Northrop Grumman. The system includes two mission computers and an automatic flight control system. Each crew station has two 8x6-inch multifunction liquid crystal displays (LCD) and one 4.2x4.2-inch dual function LCD display. The communications suite combines a US Navy RT-1824 integrated radio, UHF/VHF, COMSEC and modem in a single unit. The navigation suite includes an embedded GPS inertial navigation system (EGI), a digital map system and Meggitt's low-airspeed air data subsystem, which allows weapons delivery when hovering.[8]

The crew are equipped with the Thales "Top Owl" helmet-mounted sight and display system.[4] The Top Owl has a 24-hour day/night capability and a binocular display with a 40° field of view. Its visor projection provides forward looking infrared (FLIR) or video imagery. The AH-1Z has survivability equipment including the Hover Infrared Suppression System (HIRSS) to cover engine exhausts, countermeasure dispensers, radar warning, incoming/on-way missile warning and on-fuselage laser spot warning systems.[7]

The Lockheed Martin target sight system (TSS) incorporates a third-generation FLIR sensor. The TSS provides target sighting in day, night or adverse weather conditions. The system has various view modes and can track with FLIR or by TV.[7] The same system is also used on the UH-1Y Venom and the KC-130J Harvest HAWK.[17]

Operational history[edit]

A U.S. Marine AH-1Z lands on the USS Makin Island (LHD-8) in 2010.

The AH-1Z completed sea-trial flight testing in May 2005.[18] 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.[19] The AH-1Z and UH-1Y completed their developmental testing in early 2006.[20] 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.[21]

In February 2008, the AH-1Z and UH-1Y began the second and final portion of OPEVAL testing.[22] AH-1Z testing was stopped in 2008 due to issues with its targeting systems.[12] The AH-1Z was later declared combat-ready in September 2010.[23]

Foreign interest[edit]

On 21 September 2012, the U.S. Congress was notified of the possible purchase of 36 AH-1Z Vipers by South Korea. The request included 84 engines (72 installed and 12 spares), 288 AGM-114K3 Hellfire missiles, 72 AIM-9M-8 Sidewinder missiles, integrated missiles launchers, targeting systems, and radar jammers. The order would be worth $2.6 billion.[24] The Viper was competing against the Boeing AH-64 Apache and the TAI/AgustaWestland T-129 for the order; a decision was expected by the end of 2012.[25] In April 2013, South Korea announced they had selected the AH-64E Apache.[26]

Operators[edit]

 United States

Specifications (AH-1Z)[edit]

AH-1Z Line Drawing.svg
Front view of AH-1Z at the MCAS Miramar Air Show

Data from Bell Specifications,[7] The International Directory of Military Aircraft, 2002–2003,[28] Modern Battlefield Warplanes[5]

General characteristics

  • Crew: 2: 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)
  • Powerplant: 2 × General Electric T700-GE-401C turboshaft, 1,800 shp (1,340 kW) each
  • Rotor systems: 4 blades on main rotor, 4 blades on tail rotor

Performance

Armament

Avionics

See also[edit]

Related development
Aircraft of comparable role, configuration and era
Related lists

References[edit]

  1. ^ AH-1Z Viper enters production as substantially new aircraft (article). Flight global. 2010-12-20 .
  2. ^ Fiscal Year (FY) 2011 Budget Estimates, Aircraft Procurement, Vol. I, BA 1–4 (PDF). USA: Department of the Navy. February 2010. p. 27 .
  3. ^ 4120-15L, Model Designation of Military Aerospace Vehicles. USA: DoD. 12 May 2004 .
  4. ^ a b Bell AH-1Z page. Bell Helicopter. Retrieved 3 January 2008.
  5. ^ a b c d e f Donald, David. Modern Battlefield Warplanes. AIRTime Publishing, 2004. ISBN 1-880588-76-5.
  6. ^ Bishop, Chris. Huey Cobra Gunships. Osprey Publishing, 2006. ISBN 1-84176-984-3.
  7. ^ a b c d e f [1]. Bell Helicopter, Retrieved: 16 July 2012.
  8. ^ a b AH-1W/AH-1Z Super Cobra Attack Helicopter, USA[dead link]. Airforce-Technology.com. Retrieved: 14 January 2008.
  9. ^ "AH-1Z completes first flight". Bell Helicopter, 7 December 2000.
  10. ^ "AH-1Z/UH-1Y complete developmental testing"[dead link]. US Navy, 6 March 2006.
  11. ^ Warwick, Graham. "Bell AH-1Z upgrade to switch to new airframes". Flightglobal.com, 15 February 2008.
  12. ^ a b Trimble, Stephen. "US Navy proposes more UH-1Ys, AH-1Zs despite test phase setback". Flight International, 22 August 2008.
  13. ^ Butler, Amy. "U.S. Marines Propose AH-1Z Production Boost"[dead link] Aviation Week, 13 October 2010. Retrieved: 13 October 2010.
  14. ^ "Bell Helicopter AH-1Z Earns Navy Recommendation for full Fleet Introduction". Bell Helicopter, 4 October 2010.
  15. ^ "Bell Helicopter AH-1Z earns Navy approval for full rate production". Shephard Group Limited. 10 December 2010. Retrieved 11 December 2010. [dead link]
  16. ^ "Snakes and Rotors: The USMC’s H-1 Helicopter Program". Defense Industry Daily. 30 December 2010. Archived from the original on 14 February 2011. Retrieved 2 January 2011. 
  17. ^ Cpl. Samantha H. Arrington. "From Hueys to Harvest Hawk: Ordnance Marine arms aircraft in Afghanistan". DVIDS. 19 May 2011
  18. ^ "AH-1Z/UH-1Y complete first sea trials"[dead link], US Navy, 13 June 2005.
  19. ^ "Bell 449 SuperCobra and KingCobra"[dead link]. Jane's Information Group, 7 December 2005.
  20. ^ Milliman, John. "AH-1Z/UH-1Y complete developmental testing". US Navy, 1 March 2006.
  21. ^ "AH-1Z/UH-1Y Start OPEVAL"[dead link]. US Navy, 6 May 2006.
  22. ^ Warwick, Graham. "US Marine Corps' Bell AH-1Z and UH-1Y enter final test phase". Flightglobal.com, 20 February 2008.
  23. ^ Trimble, Stephen (30 September 2010). "USMC declares AH-1Z Viper combat ready". Flight International. Archived from the original on 2 October 2010. Retrieved 1 October 2010. 
  24. ^ Korea – 36 AH-1Z Cobra Attack Helicopters. Pacificsentinel.com, 26 September 2012.
  25. ^ Korea helicopter bids. Flightglobal.com, 26 September 2012.
  26. ^ Song, Sang-ho (17 April 2013). "Seoul to Purchase 36 Apache Helicopters". Korea Herald. 
  27. ^ "World Air Forces 2013". Flightglobal Insight. 2013. Retrieved 12 February 2013. 
  28. ^ Frawley, Gerard: The International Directory of Military Aircraft, p. 37. Aerospace Publications Pty Ltd, 2002. ISBN 1-875671-55-2.
  29. ^ BAE’s APKWS rockets integrated on Bell’s new Model 407GT - Flightglobal.com, March 5, 2013
  30. ^ AN/APG – Equipment Listing. designation-systems.net

External links[edit]