美 AeroVironment 社가 개발 중인 수소연료 추진시스템 (Hydrogen-powered) 채용 고고도 장시간/장거리 체공 무인기
(HALE, High-altitude, Long-endurance), Global Observer 의 초도비행이 지난 1월 6일 美 서부 California 州 Edwards
공군기지에서 성공적으로 이루어졌다는 소식 입니다.
이번 Global Observer 의 비행은 2010년 8월 연료전지를 이용한 초도비행 이후, 액체수소연료 추진시스템 장착에 의한
것으로는 초도비행 입니다.
아래 소개하는 동영상은 2010년 8월 연료전지를 이용한 초도비행 장면이며, 이날 초도비행 후 AW&ST 에서 보도한 관련
기사도 함께 소개 합니다.
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Global Observer makes first hydrogen-powered flight
by 95th Air Base Wing Public Affairs
1/12/2011 - EDWARDS AIR FORCE BASE,
This milestone marks the beginning of high altitude, long endurance flight testing for the demonstration and operational utility phase of this Joint Capability Technology Demonstration program.
"Global Observer has moved quickly from development and testing toward demonstrating mission-ready, affordable persistence," said Tim Conver, chairman and chief executive officer for AeroVironment, Inc., maker of the system.
"Similar to a satellite, Global Observer is the first system designed to provide a 24/7/365 unblinking eye and continuous communications link over any location on the earth's surface for as long as needed," Mr. Conver said.
"The joint AV and
The hydrogen-powered flight lasted four hours and reached an altitude of 5,000 feet above mean sea level over the
The 412th Test Wing's Global Vigilance Combined Test Force will now systematically expand the altitude and duration of test flights to validate the aircraft's high-altitude, long endurance performance.
These flights will include the Air Force's Joint Aerial Layer Network Tactical Communications Suite payload. This capability provides persistent, IP-based aerial communications infrastructure that extends communications from a Global Observer aircraft positioned at 65,000 feet above sea level. The joint operational utility of the Global Observer system will also be assessed during this flight test series for future U.S. Government, civil, and military uses.
AeroVironment says that because of its extreme endurance and range, the Global Observer can be based out-of-theater, which will further reduce operating costs and local air traffic congestion while significantly reducing risk to operational personnel. AV plans to make Global Observer systems available for procurement and for operation as a turnkey service to provide communications and remote imaging in a manner similar to satellite services, but at a much lower cost.
AV is developing Global Observer to operate as a "stratospheric geosynchronous satellite system" with regional coverage and minimal signal delay. Two Global Observer aircraft, each flying for up to a week at a time, could alternate coverage over any area on the earth, providing a seamless, persistent platform for high-value missions such as communications relay, remote sensing, long-term surveillance and border patrol.
Offering greater flexibility than a satellite and significantly longer duration than conventional manned and unmanned aircraft, AV says Global Observer is designed to provide critical new capabilities in a reliable and more affordable manner while consuming no fossil fuels and releasing no carbon emissions.
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Hydrogen-Powered UAV Begins Flight Tests
Aug 17, 2010
By Graham Warwick
Following an initial hour-long, battery-powered flight, AeroVironment’s Global Observer unmanned aircraft is beginning a test program planned to culminate in a week-long flight in the stratosphere using liquid-hydrogen fuel. The flight debuts an innovative approach to persistent surveillance and marks a dramatic departure for a company that dominates the market for small, hand-launched UAVs.
The Global Observer (GO) is flying from Edwards AFB, Calif., where it will undergo an operational utility assessment under a joint concept technology demonstration (JCTD) sponsored by several
The aircraft reached almost 4,000 ft. on its Aug. 5 first flight and conducted a series of maneuvers, including climbs and turns. After battery-powered flights to expand the envelope, the Global Observer will begin using hydrogen fuel.
Unmanned platforms orbiting in the stratosphere for extended periods could allow operators to combine the capabilities of satellites with the flexibility of aircraft. But endurance measured in days not hours requires a different approach to design and propulsion.
After experimenting with solar power, AeroVironment selected hydrogen propulsion as the most practical solution for a high-altitude, long-endurance UAV that can be launched at short notice to maintain a continuous presence at low cost for persistent surveillance, communications relay, border security, remote sensing and other missions.
“In the same way that airplanes opened the lower atmosphere to practical use, and satellites did for space, we believe that the stratosphere can be opened for practical use by Global Observer,” says Chairman and CEO Tim Conver. Covering an area 600 mi. in diameter from the vantage point of the stratosphere with an affordable, persistent platform “translates into more coverage for fewer dollars,” he says.
“Compared to conventional aircraft, GO requires fewer takeoffs and landings, which translates into lower cost,” he says. “Compared to satellites, it will be easy to reposition GO, to upgrade technology and change out payloads.” The company calculates that the GO system requires up to two times fewer aircraft and eight times fewer takeoffs and landings to maintain year-round coverage compared with conventional UAVs.
AeroVironment is better known for its small unmanned aircraft, particularly the RQ-11 Raven, thousands of which have been produced. The hand-launched, battery-powered Raven weighs 4.2 lb. and flies for 90 min. The Wasp is even smaller, and the company is developing the Switchblade, a tube-launched lethal UAV, and the Shrike, a vertical-takeoff-and-landing “perch-and-stare” micro-UAV.
The Global Observer is a return to AeroVironment’s origins in designing large, lightweight aircraft. The company was founded by Paul MacCready, whose Gossamer Condor made the first sustained, controlled, human-powered flight in 1977. This led to the development of solar-powered aircraft — the Solar Challenger crossed the
As part of NASA’s Environmental Research Aircraft and Sensor Technology (Erast) program, AeroVironment then developed a series of high-altitude, solar-powered unmanned aircraft. The 100-ft.-span Pathfinder reached 71,500 ft. in 1977, the 120-ft. Pathfinder-Plus exceeded 80,000 ft. and the 247-ft. Helios reached 96,860 ft. in 2001. All these aircraft were flying wings sheathed with photovoltaic cells.
“By the end of the Erast program, we concluded that solar power would for many years be insufficient to support continuous operation beyond the tropics in the local winter,” says Kirk Flittie, Global Observer program manager. “Since most areas of interest are beyond the tropics, by 2000 we determined that something other than solar power would be required to enable long-endurance operation, most likely involving liquid hydrogen.”
In the meantime, the Pathfinder-Plus had demonstrated cellular communications relay and high-definition television transmissions from the stratosphere, validating the concept of using a high-altitude UAV for persistent communications.
The initial design of the Global Observer was developed in 2004, a conventional layout with fuselage, tail and high-mounted wing. The requirement was to maximize endurance at 55,000-65,000 ft. while providing 2.8 kilowatt-hours of power to a 380-lb. payload. Hydrogen was chosen because its specific energy is three times that of conventional fuel.
This presented a number of design hurdles. “Storing liquid hydrogen without heavy tanks is a significant challenge,” says Flittie, and critical to achieving light weight and long endurance. “[AeroVironment] developed a unique containment technology to enable storage vessels that are significantly lighter than conventional solutions.”
The Global Observer is powered by an internal-combustion engine modified to burn hydrogen. This drives a generator that produces electricity to power the four propellers and payload and charge batteries. “Continuous internal combustion in the stratosphere, where the oxygen content is approximately one-sixteenth that of sea level, is a challenge that was addressed through a unique compression solution,” says Flittie.
Compared with the alternative of burning the hydrogen in internal-combustion engines that drive the propellers directly, the company says its all-electric power network of generator, motors and batteries provides advantages in flexibility, reliability and redundancy.
AeroVironment’s Efficient Energy Systems (ESS) electric-vehicle business developed the starter/generator, which produces about 60 kw. of electricity, of which 2.8 kw. is available to the payload. “GO is made possible, in part, by the unique capabilities within our EES business that enable this solution,” says Conver. “Without these capabilities, it would be very difficult to develop and demonstrate GO successfully.” The company declines to give details of the hydrogen containment, compression solution or power system.
To demonstrate liquid hydrogen could be used safely and efficiently, AeroVironment flew a subscale prototype in 2005. The 50-ft. wing-span, 175-lb. “GO-0” was powered by a hydrogen fuel cell and flew at low altitude. Although it switched to internal combustion for GO-1, the company believes that, as their reliability increases and costs decrease, fuel cells could be a viable power source in the future.
Despite a wing span of 175 ft., the GO-1 weighs less than 10,000 lb. The airframe is composite, drawing on the company’s experience building lightweight solar-powered UAVs. “Working with our suppliers, we developed our own process for fabricating the composite wings with a very small number of layers,” says Flittie. The airframe is also modular, to allow the Global Observer to be transported by cargo aircraft.
Global Observer is designed to orbit a target for extended periods. “Launch, climb, descent and landing would typically be remotely piloted, while loiter could be conducted via autopilot following pre-designated GPS waypoints,” says Flittie. “A human pilot would be available at all times, even in autopilot mode.”
Three GO-1s are being built under the JCTD. Initial flights will use battery power to validate the aircraft’s handling and performance. Payload test flights will use hydrogen propulsion. The second air vehicle is expected to fly late this year and operate alongside the first to demonstrate persistent coverage in an operational utility assessment. The third is a backup. Payloads include a communications relay suite and remote-observation package.
Once the JCTD is completed, the air vehicles and ground equipment will be available for additional operational assessments and mission support. How the Global Observer could transition to development and operation, as well as potential uses for the residual hardware, have yet to be disclosed by the JCTD sponsors, says Flittie.
AeroVironment, meanwhile, has a plan to launch production of the Global Observer. Conver says manufacture of the initial systems has established a supply chain and infrastructure for low-rate production of up to five aircraft a year. Blueprints for larger-scale output have been developed “and we have plans to start up that facility as demand exceeds our existing capacity,” he says. A larger GO-2 has been proposed — a 250-ft.-span aircraft able to carry a 1,000-lb. payload — but the company says its focus is on the current configuration.
Although the Global Observer would seem a world away from small unmanned aircraft systems (UAS), Conver says there are common technologies and customers. As its small UAS business has grown, the company has developed a parallel Global Observer program organization with its own design, development, integration, production and support capabilities. “The result is that we are ready for GO production transition now,” he says.
ⓒ AeroVironment, Inc.
1. 2011년 1월 6일 California 州 Edwards 공군기지에서 수소연료를 이용한 초도비행 장면
ⓒ AeroVironment, Inc.
ⓒ AeroVironment, Inc.
ⓒ AeroVironment, Inc.
2. 2010년 8월 5일 California 州 Edwards 공군기지에서 연료전지를 이용한 초도비행 장면
ⓒ AeroVironment, Inc.
3. 2010년 4월 California 州 Edwards 공군기지에서 지상시험 중인 Global Observer
ⓒ AeroVironment, Inc.
ⓒ AeroVironment, Inc.
ⓒ AeroVironment, Inc.
ⓒ AeroVironment, Inc.
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