Ramon Lopez/WASHINGTON DC
OFFICIALS AT US lighter-than-air-dirigible manufacturer Westinghouse Airships hope to establish before the end of the year a firm flight-plan for future airship production.
The previous business strategy went up in smoke, literally, when a devastating fire on 2 August destroyed the only existing Westinghouse Sentinel 1000 non-rigid airship and its hangar, at the firm's Airship Flight Center at Weeksville, North Carolina.
Over the next few months, company officials will decide whether to replace the Sentinel 1000 or build an improved model instead. They must also determine where to re-establish the company's airship production and support services.
Meanwhile, they await a clear signal from the US Department of Defense and US lawmakers on the future of the US Navy's large-airship programme, which has moved at a snail's pace over the past decade.
The company believes that the fire was accidentally started by a welding firm hired to repair the doors of the leased hangar - one of the largest wooden structures in the world before it was consumed by fire. The hangar was one of six built by the US Navy to house ZPG-3W airships during and after the Second World War.
The factory was used, by Westinghouse Airships for Skyship 500/600 and Sentinel 1000 manufacturing, repair and support. The loss in lighter-than-air vehicles, property, equipment and spares will total millions of dollars.
The Weeksville plant, handled regularly scheduled maintenance, for the six Skyship 500s and 600s in North America. The US firm has set up a temporary support base in the Baltimore, Maryland, area and customers have suffered no break in service, says William Adams, Westinghouse Airships chairman and chief executive.
OPEN OPTIONS
"We are still planning our future. All kinds of options are on the table," says Adams. A survey is being conducted of the remaining airship sites in the USA, and the firm is evaluating overtures from state and local governments for construction of a new manufacturing and support site.
The 67m (220ft)-long helium-filled Sentinel 1000 was claimed to be the largest non-rigid airship built and was certificated by the US Federal Aviation Administration in November 1993. It was a one-half-scale model of the YEZ-2A, which Westinghouse wanted to build for the Pentagon.
A decision on whether to replace the Sentinel 1000 remains to be made. Westinghouse Electric, the parent of the airship manufacturer, has yet to approve production funds for a replacement, or for an improved airship, which exists on the drawing board. The firm is seeking new customers, which might contribute to airship construction. In the interim, Westinghouse Airships will be unable to undertake an airship demonstration to the USN, which had been scheduled for late 1995
Despite the setback, Adams is buoyant about the prospects for selling modern airships to the US military, other US Government organisations and commercial customers such as FedEx, which has explored using airships for overseas package shipment.
Adams says that senior USN officials and US lawmakers continue to support planned operational trials in 1998 of the YEZ-2A, first proposed in the mid-1980s. They want to see whether an airship can provide continuous and extended surveillance for low-flying cruise missiles targeted at USN warships.
Earlier in the programme it was estimated that the YEZ-2A would cost $440 million to build. It is believed that a major redesign of the propulsion system and gondola will allow Westinghouse to build the giant non-rigid airship for $275 million. The mission-avionics suite would be extra, estimated to cost $120 million.
An USN request, for $60 million in initial airship production funding, is before the US Congress. Adams says that, "the redesign, allowed us to reduce the gondola's complexity and take a lot of cost out of the programme".
The Sentinel 1000's top speed is 60kt (110km/h) and its maximum altitude is 8,000ft (2,440m). The YEZ-2A will be 143m long, achieve a top speed of 87kt and float to 15,000ft. Its envelope, with a Kevlar outer ply, will be seven times larger than that of the Sentinel 1000.
'X' TAIL DESIGN
The Sentinel 1000 has an "X"-configured tail design. Flight-control surfaces are directed by a "fly-by-light" fibre-optic-signaled flight-control sys- tem (FCS). The dual-computer FCS was developed by GEC Marconi Avionics and includes a side-stick controller and a three-axis autopilot.
The precursor to the YEZ-2A, is powered by two modified Porsche car engines, mounted on the gondola. Engineering manager Charles Klusmann says that the YEZ-2A will have two engines mounted on a beam, which runs through the envelope and a single, tail-mounted, sprint engine. Westinghouse had originally planned to use Italian-made CRM diesel engines designed for small navy coastal vessels. The YEZ-2A will now be powered by three up-rated German-made Zoche ZO-04A compound engines, each offering 1,490kW (2,000hp) take-off power. The YEZ-2A will have the same FCS as that of the Sentinel 1000.
The YEZ-2A's pressurised gondola, to be constructed of either aluminum or composites, has gone through a radical redesign, says Klusmann. Originally to have been 26m long on three decks (including the pilot's compartment), it will now be a simpler, less-costly, 31m-long one-deck design.
The YEZ-2A will have an endurance of 48h between refueling by naval vessels. The idea is to keep it on-station for up to 30 days. It would loiter as far as 80km away from a naval battle group, with the operating distance limited to the range of the datalink. Two pilots and ten to 15 others would operate the giant non-rigid airship, the first to be built to full military standards.
Westinghouse and the USN have yet to determine which radar will be mounted within the helium-filled envelope, but the Westinghouse APG-66 and Texas Instruments APS-134 and APS-137 radar have been suggested.
According to Adams, an analysis performed by the USN in 1993 indicated a requirement for as many as 20 YEZ-2As. At a cost of $275 million apiece, an USN airship production programme alone could be worth $5.5 billion.
Adams says that the US Army "...could very likely join the programme". Westinghouse is floating the idea of using military airships to protect Patriot air-defence missiles. He says that the concept is backed by the Pentagon.
The US defence department is studying whether airships can help in the rapid transfer of military equipment and troops. Westinghouse has made an approach. Lockheed Martin's Skunk Works is developing a lighter-than-air cargo-lifter design of its own.
Westinghouse believes that the US Marine Corps should use unmanned sensor-laden airships to monitor future combat operations. Adams says that government agencies worldwide should also consider using airships for maritime-surveillance, border-patrol and internal- security missions.
As design work continues on the naval airship prototype, Westinghouse engineers are separately developing a follow-on to the Sentinel 1000. The proposed Sentinel 1240 would be slightly larger than its predecessor, with a new gondola, 15m long, designed to accommodate 40 passengers. A 12m-long 20-passenger gondola is envisioned for the Sentinel 1000.
The Sentinel 1000/1240 would be powered by two basic ZO-04A eight-cylinder, radial diesel engines. The Sentinel 1240 may also have a single, tail-mounted, sprint engine. A simpler FCS may be installed for commercial operators.
Westinghouse Airships' future production and support site will have to be larger than the one at Weeksville, which is not big enough to build the YEZ-2A. Potential sites include Moffett Field, California, and Lakehurst, New Jersey, where Second World War-era ZPG-3W airships were housed. The Hindenberg, the world's most famous airship, exploded into flames while mooring at Lakehurst in 1937.
During the Second World War, Navy airships compiled an almost perfect record as fleet escorts, and Adams believes that the USN leadership and other potential customers for modern airships should look "back to the future" in considering whether "...the [modern] airship's time is about to come".
Source: Flight International
