http://www.dsti.net/Information/News/73734
美國公開X-56A最新X研究機
2012-02-03
[據美航宇日報2012年2月1日報導]美國空軍最新型X系列研究機X-56A將研究主動控制技術在未來高空長航時(HALE)偵察飛機上的潛在應用。X-56A飛翼飛機由洛•馬臭鼬工程隊設計,該機是一種創新型模組化無人機,將用於試驗主動顫振抑制和陣風減緩。這些技術被視為對瘦長輕型大展弦比機翼在未來運輸機和情報、監視與偵察(ISR)無人機上的成功應用至關重要。在完成美國空軍試飛任務後該機還將轉由NASA進行研究試飛。
該無人機原名為多用途技術試驗台(MUTT),主要開展可能出現顫振的飛行包線邊界的試驗。顫振是翼面的自激振動,是飛行器上出現的一種破壞性振動,一旦飛行速度超過臨界值,振幅就迅速增大,以至機翼破壞。為了應付試驗中可能出現的機翼脫落,X-56A飛機機身內安裝了彈道降落傘改出系統。
X-56A安裝2台JetCat P240渦噴發動機,採用方便機翼更換的構型,試驗中該機將用固定翼和多種柔性機翼開展試驗。該機後機身上部有一承力點,可用於裝備第3台發動機或結合機翼翼梁,進而開展先進氣動構型的試驗。
該翼展為28英尺(8.5米)的飛機是美國空軍研究實驗室(AFRL)領導的多用途氣動彈性驗證專案(MAD)的關鍵試驗設施,並還將對AFRL SensorCraft(一組用於偵察、無線電通訊中繼及環境遙感的HALE飛行器)項目後續研究工作提供幫助。在完成美國空軍相關試飛後,X-56A將由NASA德萊登飛行研究中心使用,進行輕型結構和未來低排放運輸機相關先進技術的研究。NASA試飛工作將在亞聲速固定翼專案下開展,將有助於開發主動動態結構控制的規範與方法,並提供科研用經過驗證的飛機模型。
X-56A繼承了以往洛•馬SensorCraft飛機簡潔設計風格和P-175、RQ-170 及“暗星”無人機的飛翼型設計,採用倒海鷗式三角形構型。該機飛行試驗方案包括2個7.5英尺(2.9米)長的中機身和4套固定弦機翼。1套機翼將是基本試飛用剛性機翼,也可用於後續研究,剩餘3套機翼將是3套相同的顫振試驗用輕型蒙皮材料製成的柔性機翼。
X-56A目前正在GFMI航宇與國防公司進行總裝,該公司是加州一家專門進行原型機和樣機研製的工程公司。目前飛機計畫在4月底交付給洛•馬公司,今年6月運抵愛德華茲空軍基地。該機在美空軍第452飛行試驗中隊的試驗飛行計畫7月份在北部基地開始,並一直持續到9月份。X-56A計畫今年底前轉交給NASA。(中國航空工業發展研究中心 吳蔚)
http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=aerospacedaily&id=news/asd/2012/02/01/02.xml&headline=USAF%20Reveals%20Latest%20X-Plane:%20X-56A
USAF Reveals Latest X-Plane: X-56A
Feb 1, 2012
By Guy Norris
EDWARDS AFB, Calif. — A new U.S. Air Force X-plane designated X-56A will explore active control technology for potential use in future high-altitude, long-endurance (HALE) reconnaissance aircraft.
Designed by Lockheed Martin’s Skunk Works, the X-56A flying wing will also later be flown by NASA, and is an innovative modular unmanned air vehicle designed to test active flutter suppression and gust load alleviation. These technologies are considered vital for the successful development of the slender, lightweight, high-aspect-ratio wings that could be used by future transports as well as intelligence, surveillance and reconnaissance UAVs.
Formerly dubbed the Multi-Use Technology Testbed (MUTT), the UAV will test to the edge of the flight envelope where flutter occurs. Flutter is the potentially catastrophic dynamic coupling that can occur between the elastic motion of the wing and the aerodynamic loads acting on it. If a test goes too far and a wing fails in flight, the X-56A is fitted with a fuselage-mounted ballistic parachute recovery system.
Powered by twin JetCat P240 turbojets, and configured for easy wing replacement, the aircraft will be tested with stiff wings as well as multiple sets of flexible wings. The design also includes a hard point on the center upper deck of the aft fuselage that can either be adapted to house a third engine or the boom for a joined wing, thereby enabling testing of more advanced aerodynamic concepts.
The 28-ft.-span vehicle is the key test asset for the Air Force Research Laboratory-led Multi-utility Aeroelastic Demonstration Program (MAD). This is contributing to AFRL’s follow-on work to SensorCraft, a class of HALE vehicles intended for surveillance as well as telecommunication relay and environmental sensing. Following Air Force flight tests, the X-56A will be used by NASA’s Dryden Flight Research Center for further work also aimed at lightweight structures and advanced technology for future low-emissions transport aircraft.
AFRL MAD Program Manager Pete Flick says the SensorCraft studies “led us to very different configurations that are inherently more flexible with high-aspect-ratio wings. Gust-load alleviation and flutter suppression are two key technologies we needed to pursue, and there was no testbed out there where we could test active flutter suppression without a lot of risk. So we went out to develop a vehicle specifically for that purpose. So that’s what motivated AFRL, and to work with NASA, which has a similar interest in pursuing configurations for future aircraft.”
The NASA flights will be conducted under the subsonic fixed-wing project and will help to develop guidelines and methodology for active dynamic structural control as well as provide flight-validated aircraft models for academia. The aeroelastic and lightweight structures research will also contribute toward long-range planning for the proposed X-54 low-boom supersonic demonstrator program.
Displaying clear design heritage from previous Lockheed SensorCraft concepts as well as flying wing designs including the P-175 Polecat, RQ-170 and DarkStar UAVs, the X-56A is characterized by a cranked delta planform. The flight-test package will include two identical center bodies measuring 7.5 ft. long, as well as four sets of constant-chord wings. One set will be stiff for baseline flight tests, as well as follow-on research, while the remaining three will be identical flexible wings made with lighter skin material for flutter testing.
The X-56A is in final assembly at GFMI Aerospace and Defense, a Fountain Valley, Calif.-based engineering company specializing in prototype and mockup development. The aircraft is currently due to be delivered to Lockheed Martin in late April and will be transported to Edwards AFB in June. Flights with the 452nd Flight Test Squadron, part of the 412th Test Wing, will begin at the North Base in July and continue through September. Following an approximately 25-hr.-long flight test effort, the X-56A is expected to transfer to NASA by year’s end.