Hybrid Air Vehicles HAV-3
|HAV-3 scale prototype first flight at Cardington.|
|Role||Optionally-manned ISR/transport hybrid airship|
|Manufacturer||Hybrid Air Vehicles
|Status||military version cancelled, civilian development restarted as Airlander|
|Primary user||United States Army (planned)|
|Number built||1 prototype as of June 2010|
The aircraft was selected by the United States Army for its Long Endurance Multi-intelligence Vehicle (LEMV) programme in which Northrop Grumman was to have been the prime contractor. The LEMV was intended to provide intelligence, surveillance and reconnaissance (ISR) support for ground troops through unmanned, Medium-altitude long-endurance unmanned aerial vehicle operations. On 7 August 2012 the first test flight of an LEMV was completed in Lakehurst, New Jersey. The vehicle tested was one of three planned for the US Army.
The US Army cancelled the LEMV project for cost reasons in February 2013. HAV bought back the airship in September 2013 for $301,000. In 2014 - named Airlander - it was reassembled at RAF Cardington in England.
Development and design
The first HAV-3 craft was a scale model based on the Skycat concept, developed by Hybrid Air Vehicles (HAV). It was submitted as a scale demonstrator for the US Army's Long Endurance Multi-intelligence Vehicle (LEMV) project;
HAV 304 and the LEMV project
With Northrop Grumman as the prime bidder, the HAV hybrid airship concept was accepted for the US Long Endurance Multi-intelligence Vehicle (LEMV) project, in preference to the Lockheed Martin P-791 also submitted.
Requirements included the capability to operate at 6 km (20,000 feet) above mean sea level, a 3000 km (2,000 mile) radius of action, and a 21-day on-station availability, provide up to 16 kilowatts of electrical power for payload, be runway independent and carry several different sensors at the same time. According to the U.S. Army, the LEMV was to have been a recoverable and reusable multi-mission platform. It could be forward located to support extended geostationary operations from austere locations and capable of beyond-line-of-sight command and control.
The agreement to develop the project was signed on June 14, 2010, between the U.S. Army Space and Missile Defense Command/Army Forces Strategic Command and Northrop Grumman. The agreement also included options for procuring two additional airships.
Northrop Grumman's subcontractors included:
- Hybrid Air Vehicles Ltd. in Cranfield, UK (HAV304 platform)
- Warwick Mills in New Ipswich, NH (Fabrics engineering)
- ILC Dover in Kent County, DE (Airship manufacturer and designer)
- Textron subsidiary AAI Corp. in Hunt Valley, MD (Makes the US Army’s OneSystem UAV/surveillance aircraft control & information distribution stations); and
- SAIC in McLean, VA.
The developmental prototype emerged as the HAV 304, having an internal capacity of 38,000 cubic metres. At 91 m long, it is the longest aircraft in the world today. This compares to the German Hindenburg-class airships which were 245 m (803 ft 10 in) long.
Its first flight took place on 8 August 2012 at Joint Base McGuire-Dix-Lakehurst.
The project cost between $154 million and $517 million, dependent on all options. The cost included the design, development, and testing of the airship system within an 18-month time period, followed by transportation to Afghanistan for military assessment.
Return to the UK
Following cancellation of the LEMV project, the HAV 304 was repurchased by HAV and returned to the UK, where it is hangared at RAF Cardington.
The Airlander 50 is a proposed commercial development of the HAV304, intended to have a 50 tonne payload.
HAV 304 design:
- Length: 91 m (298 ft 7 in)
- Width: 34 m (111 ft 7 in)
- Height: 26 m (85 ft 4 in)
- Envelope: 38,000 cubic metres
- Engines: four x 350 hp, 4 litre supercharged V8 diesel
Combined with an array of payloads - including ground moving target indication radar, electro-optical/infra-red sensors, communications relay, blue force tracking, signals intelligence, and electronic countermeasures - the LEMV would have augmented existing ISR platforms to provide additional capabilities. The LEMV was intended to provide a possible solution to communications beyond the line-of-sight to the user, signals intelligence collection and almost any other type of payload configuration that meets the power, weight and size requirements. By providing this all-source sensor data to existing ground stations, the data would be available to multiple users and analysts. This interoperability with existing tasking, processing exploitation, and dissemination had the potential to improve information-poor situations, mitigating Warfighter gaps and existing shortfalls through multi-intelligence sensor integration.
The LEMV would have enabled the DoD to fly the most technologically advanced payloads in the near term as they became available. Northrop Grumman designed their system to integrate into the Army’s existing common ground station command centers, and equipment used by ground troops in forward operating bases. The LEMV could also be used to move heavy equipment while in Afghanistan, a massive advantage over competing UAVs.
The airship was a hybrid air vehicle (HAV) and had a number of advantages over fixed-wing unmanned aerial vehicles (UAVs). A HAV uses aerodynamic lift like a conventional airplane to take off before using helium to keep it in the sky once it is airborne. Engines on board are then used to move while it monitors events on the ground. The LEMV’s skin - a blend of Vectran, Kevlar, and Mylar - would have been able to cope with a “reasonable amount of small arms fire.” Northrop estimated that the biggest threat to the craft was weather, where high winds or thunderstorms could buffet the craft.
While reconnaissance can be undertaken by airplanes, the costs involved for such a flight were estimated in 2010 to be $10,000–20,000 per flight hour, plus an additional $10,000 in recapitalization costs. Helicopters are more affordable than their fighter equivalent, and can intervene like fighters if weapons are needed, but they are noisy and vulnerable, have very low endurance, and are still not cheap to operate. Hybrid airships can operate from any small forward base, like a helicopter. Their operating cost is likely to be better than any other surveillance option, as is their endurance, which can be measured in weeks. The LEMV required no less than 1000 feet of runway (violating the runway-independent requirement), and required a tether point with 360 degrees of 300-foot smooth area to park, which restricted them from operating at most large bases and all small bases.
They could serve as steady communications relays, for instance, ensuring that groups of soldiers in mountainous areas never lose contact with one another, even if they do not have direct line of sight to each other. LEMVs could have tracked important convoys, key roadways, or other key infrastructure as semi-permanent overwatch escorts, monitor an urban area of interest to prepare for major battles or enforce security, or focus on shutting down border chokepoints.
According to Alan Metzger, director for airship programmes at Northrop Grumman, the airship’s ability to stay in the air for long periods made it perfect for surveillance missions. Speaking to The Engineer magazine, Mr Metzger claimed that the LEMV was “going to be the longest endurance UAV in the world. There will be no gaps in the data that gets put down to the war-fighter.” Northrop also said the LEMV could be used as a cargo aircraft, claiming that it had enough buoyancy to haul seven tons of cargo 2,400 miles at 30 miles per hour.
Construction and first flight
The timeline for LEMV was an 18 month schedule starting in June 2010 that includes vehicle inflation at about month 10. Additional operational characterization will occur at Yuma Proving Ground, Ariz., in month 16.
The Army was slated to demonstrate the first LEMV in Afghanistan 18 months after June 2010, with proposed plans to build five others following mission completion.
The overall concept has been struggling with constant time delays and technological challenges. In October 2011 Flight International reported that the LEMV would be ready for its first flight in November 2011. According to media reports the LEMV was then set up for its first flight in early June 2012. However, unspecified problems delayed the flight even further. The first flight of the LEMV took place on August 7, 2012 over Joint Base McGuire-Dix-Lakehurst, New Jersey. The flight lasted for 90 minutes and was performed with a crew on board. The first flight primary objective was to perform a safe launch and recovery with a secondary objective to verify the flight control system operation. Additional first flight objectives included airworthiness testing and demonstration, and system level performance verification. All objectives were met during the first flight. That put the combat deployment of the LEMV to Afghanistan in early 2013. However, two months after the test flight, the Army said it had concerns about sending the airship abroad. These included safety, transportation to the theater of operations, and the timeline of deployment.
On 14 February 2013, the Army confirmed that it had cancelled the LEMV development effort, citing technical and performance challenges, as well as the limitations imposed by constrained resources.
Hybrid Air Vehicles, the company which developed and helped build the airship, expressed interest in purchasing the airship from the Army before the craft was to be dismantled. Ostensibly, they would use it for cold- weather flights and other testing for the development of their "Airlander 50" 50-ton cargo airship. It was the only interested party - offering to purchase the aircraft, mooring masts and spare engines. In September 2013, the Pentagon sold the LEMV airship back to HAV for $301,000, a fraction of the $297 million spent on development. The cameras, sensors, and communications equipment were removed and the helium was drained before the sale. The Army maintains that the project's technical data and computer software could be useful for future projects and that selling it would save money.
- TCOM Blue Devil, US Air Force project for reconnaissance airship
- Cargolifter, a company proposing heavy lift airships
- Lockheed Martin P-791
- Walrus HULA - DARPA project for transport
- RAF Cardington
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