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Aviation History
2001
2001 - 2565.PDF
.„,,. 1. E±Z*^^ -JIM. . ggp developed by EADS for the German navy and forming the main technology focus for the NATO Project Group 35 naval UAV demonstration programme. The USN also undertook an extended evaluation of rotary wing technology in 1998, including flight trials of the Bell Eagle Eye aVd Bombardier CL-327. Based on the outcorhe of that programme, many analysts believed the Eagle Eye would win the USN's VTUAV competition. The subse quent choice of the Firescout over the Eagle Eye is generally seen to reflect a major price differential between the two bids, and the need for tiltrotor technology to mature further. This point was dramati cally brought home by last year's crashes of the Bell-Boeing V-22 Osprey being built for the US Marine Corps. According to Long, at least part of the reason for the extended gap between the QH-50 and the Firescout has been that fixed wing systems were "things that peo ple know best. They have a glide ratio bet ter than a rock and people tend to think that they are a little bit safer. We have done a lot of research in those areas. Helicopters themselves are not the most stable of sys tems., .even with a pilot on board, they are pretty tricky to fly. You have got to counter torque and those sorts of issues." VTOL UAV development has been littered with more than a frequent spatter ing of failures. Bombardier, for example, has pioneered co-axial rotor VTOL UAVs with its CL-327 design flying for close to a decade. In 1995, without firm orders, the company optimistically put the CL-327 into production. But six years later, it still awaits buyers despite having participated in extensive international demonstration programmes and trials. History of losses The CL-327 has also racked up a history of losses. In 1998, while participating in the USN's VTOL demonstration programme at Yuma proving grounds in Arizona, a CL- 327 lost its fuel tank in flight and crashed. Bombardier said that the accident was caused by structural failure which would be rectified through design changes. In August 1998, two months after the crash, a three-month-long Australian Army demonstration programme was terminated in mid-course after one of two leased CL-327s also crashed, destroying the only available sensor payload. Sikorsky has experimented with ducted fan designs since the early 1990s, eventu ally securing a US Marine Corps contract to demonstrate an evolved form of its Cypher UAV under its Dragon Warrior pro gramme. Last December, however, the USMC decided to shelve that demonstra tion due to slower than expected progress in development of the Cypher II air vehi cle, handing it over to the US Army to troubleshoot. Sikorsky acknowledged major mechanical problems associated with the development of a two-engine drive-train at the time, but has since devel oped a solution. The EADS Seamos has had similar diffi culties since development first commenced in the late 1980s to support the German navy, leading to the replacement of its engine and navigation systems. EADS' sole demonstrator air vehicle was severely dam aged in a crash during tethered flight in mid-1999, but this was caused by the fail ure of part of the anchoring system and not air vehicle problems. EADS is continu ing development with a programme of sea trials which commence next year as part of the NATO PG35 programme. Even the Firescout has had problems. The first test vehicle crashed in November www.flightinternational.com FLIGHT INTERNATIONAL 10-16 JULY 2001 43
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