X-51 极超音速飞行失败 X-51A“乘波者”采用美国普惠公司制造的“空气式超音速燃烧冲压引擎”,可在数秒内加速到每小时4500英里(约7242公里),接近6倍音速。 这架世界顶尖的飞行器将由B-52轰炸机从美国加利福尼亚州的爱德华兹空军基地运载至太平洋上空进行全新测试。“乘波者”将在慕古角附近的5万英尺(约15240米)高空同B-52分离,一台火箭助推器将被随即点燃,把“乘波者”的时速提升至4.5马赫。如果一切顺利,“乘波者”的引擎会在这一节点启动,把飞行速度继续推进至6马赫,把飞行高度抬升至7万英尺(约21330米)。此次测试任务预计用时300秒,这将是该飞行器迄今为止最长的飞行时长。测试结束后,“乘波者”将自动解体并坠入大海,有关方面没有任何后续的打捞计划。 美国空军研究实验室(AFRL)高速系统部门负责人罗伯特·默西埃表示:“获得持续极超音速飞行器就好比是从螺旋发动机迈入喷气发动机。自莱特兄弟以来,人类已经在尝试制造更好、更快的飞机。极超音速飞行器无疑是航空学的一个前沿领域,我认为我们正准备进入新的竞技场。” “乘波者”项目预计花费在8900万英镑(约人民币8.88亿元),由美国国家航空航天局(NASA)和五角大楼出资,旨在能将其应用于隐形飞机和新式武器。 最新消息, The U.S. Air Force says its most ambitious test of its X-51 WaveRider hypersonic aircraft ended in failure less than a minute after launch on Tuesday, due to a flaw in one of the craft's control fins. The X-51 broke apart after it was dropped from a B-52 bomber, with pieces falling into the Pacific Ocean, a spokesman for the project told me today. If the test had proceeded as planned, the Boeing-built X-51 would have shot through the sky for a five-minute flight at a speed of up to 3,600 mph (5,800 kilometers per hour), or six times the speed of sound. Instead, the Air Force is going back to the drawing board. Hypersonic scramjet propulsion has been widely touted as eventually opening up the way for flights between London and New York in less than an hour. But in reality, the first application is more likely to come in the form of super-fast cruise missiles. (Scramjet is a short term for "supersonic combustion ramjet," and there have been many efforts through the years to perfect scramjet-powered aircraft.) In a statement, the Air Force said the unmanned craft was successfully launched from the B-52 over Point Mugu Naval Air Warfare Center Sea Range, in the Pacific near California's coast, at about 11:36 a.m. PT (2:36 p.m. ET) on Tuesday. The X-51's rocket booster fired as planned — but 16 seconds later, a fault was identified with the cruiser control fin, the Air Force said. When the X-51 separated from the booster, about 15 seconds later, the cruiser couldn't maintain control and was lost. "'Came apart' is the term that they used," said Daryl Mayer, a spokesman for the Air Force's 88th Air Base Wing at Wright-Patterson Air Force Base in Ohio. The WaveRider never had a chance to reach supersonic speed. "It is unfortunate that a problem with this subsystem caused a termination before we could light the scramjet engine," Charlie Brink, X-51A program manager for the Air Force Research Laboratory, said in today's statement. "All our data showed we had created the right conditions for engine ignition, and we were very hopeful to meet our test objectives." The Air Force said the control system had proven reliable during the X-51A's two previous flights — including a successful test in May 2010 and a not-so-successful test in June 2011. Today's statement said program officials will conduct a "rigorous evaluation" of this week's test to assess all the factors behind the failure. One of the four X-51A vehicles remains, but officials have not decided when or if that vehicle will fly, the Air Force said. The X-51 project's cost has been estimated at $140 million. |