Ramon Lopez/WASHINGTON DC
Events taking place 10,000km (6,200 miles) apart could prove pivotal to the long-awaited deployment by military forces of vertical take-off and landing (VTOL) unmanned air vehicles (UAVs).
US Navy officials now believe that VTOLUAV technology is mature enough for the service to begin equipping its warships with the pilotless aircraft. This assessment is fuelled by successes in the US Department of Defense's (DoD) VTOL UAV demonstration under way at the Yuma Proving Grounds in Arizona since March. This was scheduled to end on 11 June.
Acquisition of a VTOL UAV remains in limbo, however, pending the outcome of a critical test of the Alliant Techsystems Outrider joint tactical UAV and the issue of a US military requirements document for a VTOL UAV.
Meanwhile, UAVs have gained the attention of other navies, leading to development of a NATO Staff Requirement for a maritime unmanned air vehicle (MUAV) system.
A key MUAV demonstration is intended to form the basis of an international collaborative development by member countries. This was to have taken place in April, but technical problems have pushed it back to later this year, opening the door for wider industry involvement.
Although there are, as yet, neither plans nor funds to procure a VTOL UAV, the successful four-month flight test demonstration, involving three designs, has led the Pentagon's UAV Joint Project Office (JPO) to plan a fast-track acquisition programme.
MARITIME REQUIREMENTS
Elsewhere, USN officials are finalising the Operational Requirements Document (ORD) for a VTOL tactical UAV (VTUAV). This updates the Navy and Marine Corps' VTOL Integrated Platform for Extended Reconnaissance UAV requirements document, shelved in 1992 because of a lack of funding. The US Army is also participating, leading to speculation that the Outrider has lost favour with its leadership.
"The technology is demonstrating its maturity, and the warfighters want it for their ships," says USN Capt Lyn Whitmer, programme manager for naval UAVs.
Steve Hogan, deputy programme manager for naval UAVs, believes that "-VTOL technology is available that could be applied to satisfying an ORD". An industry official concludes: "There is no doubt the US Navy and US Marine Corps will eventually move to a VTOL UAV".
Last year, the US Congress tasked the Navy with evaluating the maturity of VTOL UAV technologies, concentrating on air vehicle performance. Congressional backers of the Bombardier CL-327 Guardian VTOL UAV added $15 million to the DoD's fiscal year 1997 budget to test the vehicle. The UAV JPO won permission instead to conduct competitive land-based trials of the CL-327, the Bell Helicopter Textron Eagle Eye and the Science Applications International (SAIC) Vigilante.
US lawmakers provided an extra $8 million in FY1998 to continue development of a VTOL UAV and to initiate a proof of concept project involving the Boeing Canard Rotor/ Wing design. For FY1999, they have earmarked more funds to exercise options to the demonstration contracts for VTOL UAV sea trials in the January 2000 timeframe. They have also budgeted for air vehicle integration with the Sierra Research UAV Common Automated Recovery System and the Tactical Control System (TCS), a common ground control station.
OUTRIDER DECISION
Procurement planning remains notional pending military budget deliberations and evaluation of test results from the land-based VTOL UAV trials and the Outrider military user assessment taking place at Fort Hood, Texas. This is due to conclude in June.
As it stands, full procurement of the Outrider calls for 73 systems: 38 for the US Army, 11 for the Marine Corps, 20 for the Navy and four training systems.
The Navy and Marine Corps say that they will decide in late June or early July whether to stick with the fixed wing, gasoline-powered Outrider or switch to a VTOL UAV powered by a heavy-fuel engine (HFE) to satisfy their TUAV requirement.
Whitmer says that USN fleet commanders have long backed the deployment of VTOL UAVs because they "-no longer want to see UAVs hurled into nets [the recovery method for the current Pioneer shipborne UAV]". Adm Jay Johnson, Chief of Naval Operations, has said that "-it is important to determine if there are valid fleet requirements for a VTOL UAV which may well provide important capabilities-that fixed wing UAVs can't provide".
Bell's Eagle Eye is a tiltrotor UAV powered by an Allison C20B turboshaft. The demonstrator flown at Yuma is a 7/8th-scale model of a production air vehicle. Operated with a FLIR System's Ultra 3000 forward looking infrared and television payload, the tiltrotor UAV was the first to complete the 50h flight demonstration - despite being grounded briefly after a gearbox was damaged. During the tests, the flight envelope was expanded to 14,600ft (4,450m) altitude and a 200kt (375km/h) dash speed while carrying a 95kg (210lb) payload.
Bombardier's CL-327 Guardian is a co-axial rotor helicopter powered by a Williams International WTS-117 turboshaft. Up to 5 June, the demonstrator had made 35 flights, totalling nearly 44h, and was on track to complete 50h before the 11 June deadline. The vehicle has flown hands-off missions using autonomous waypoint navigation, achieving an altitude of 9,100ft. Flights lasting more than 4h have also been conducted.
The Guardian is being operated from a high mobility multi-wheeled vehicle ("hummvee") and trailer, with a scaled-down UAV ground control station, an Elta C-band digital datalink, a back-up short range L-band datalink and the Ultra 3000 sensor package.
There were delays with installing the longer range C-band datalink, but "-overall, there were no major mishaps, and we showed that Guardian is extremely reliable", says the Canadian manufacturer.
SAIC did not begin flying the Vigilante at Yuma until the end of May because of technical problems, including a crash on 20 April. By 5 June, the Ultra 3000-equipped Vigilante had completed only 10 flights lasting for a total of 4.4h, making it difficult for the company to complete all required tests by the deadline.
The Vigilante demonstrator is built around the American SportCopter Ultrasport 496, a small kitbuilt helicopter which costs $49,000. Its 86kW (115hp) German-made Hirth two-cycle gasoline engine allows for a top speed of 117kt, but an HFE installation is planned: either the WTS-117 or a Zoche diesel radial in development, allowing for greater endurance and higher dash speed.
The draft requirements document says the VTUAV will replace the Pioneer UAV now deployed with Navy and Marine Corps units. The VTOL UAV can use JP-5, JP-8 or diesel fuel - with a top speed of 150kt - and it must be able to carry a 91kg payload. The vehicle must have a combat radius of at least 205km (110nm), be capable of reaching the outer mark in 1h, remain on station for 3h, and return to its original launch point without refuelling.
The draft ORD makes mandatory use of the TCS and specifies an electro-optical/infrared sensor with laser designator. It also calls for initial deployment of the VTUAV in 2001 to avoid a Pioneer service life extension programme, but project officials see problems with that date.
They say that initial deployment in 2003 or 2004 is achievable, especially if they are allowed to move directly to a three-year engineering and manufacturing development (EMD) programme. They see this as a low-risk "feasible proposition" given the number of previous VTOL UAV demonstrations.
Plans call for an open competition. A favoured option would carry several contractors through a portion of EMD, but funding constraints could prompt a "paper downselect."
Bell, Bombardier and SAIC have been asked to provide life cycle cost estimates for production systems. A baseline procurement of 23 VTOL UAV systems (each with four air vehicles) is envisioned: 11 for the USN, 11 for the USMC and one training system. The Army and Coast Guard are monitoring the project and the requirement for VTOL UAVs could grow.
BOMBARDIER WORRIES
Bombardier officials are worried that the draft ORD's dash speed requirement will penalise the CL-327, which can achieve only 85kt. If top speed becomes an issue, the company will offer the in-development CL-427 Puma, with an enlarged fuel cell, greater lift and new aerodynamic fairings. Powered by the Williams WTS-125, the Puma's advertised dash speed is 120kt.
The Pentagon, meanwhile, is part of Project Group 35 (PG35), of the NATO Naval Armaments Group, which two years ago set up the trilateral MUAV International Technology Demonstrator Programme (ITDP).
In Phase 1 of the ITDP, the USA is contributing the TCS, while Germany is providing the Daimler-Benz Aerospace (Dasa) Seamos VTOL UAV demonstrator, evolved from the US Gyrodyne QH-50D drone.
Under Phase 2, the UK will provide the MUAV datalink. An agreement between the USA and UK is close to being finalised. Phase 3 calls for land-based flight tests of a MUAV system in the 2002 timeframe, culminating in sea trials during Phase 4.
Dasa has suffered problems with the autopilot and navigation systems, however. A Seamos/TCS land-based demonstration due in April has been delayed until late this year and a follow-on test has been pushed to mid-1999.
PG35 officials are considering alternative VTOL UAVs. They view the MUAV contenders as possible alternatives to Seamos.
Bell would like the Eagle Eye to be tested as part of the ITDP, but sees a funding issue. Bombardier would like to have the CL-327 participate in the PG35 sea trials, either as a replacement for the Seamos or alongside it.
Source: Flight International
