英语沙龙:高科技神话 隐形航空电子技术(在线收听

Vaunted Technology: Stealth Avionics

Northrop Grumman Corp.(NGC)boasts on its Web site the B-2spirit stealth bomber is nearly invisible.Because the plane’s composite materials and bat-shaped design make it hard for radar to pick up.However,in 1999,an F-117,which also has a stealthy shape and materials,was blasted out of the sky over the Balkans.Stealth technology is hardly a sham.It shrinks the radar“signature”of a plane.If a conventional aircraft makes a blip on radar screens at 200kilometers,a stealthy plane wouldn’ t appear until it was 34km away.The point is,radar does eventually detect the plane.Weather can also present a problem.The B-2’s materials were tested at Edwards Air Force Base,where it rarely rains.But when the high-tech bombers got drenched during missions in the Balkans,the tape used to fill seams in the composite skin often came loose.That en larges the radar signature.

高科技神话:隐形航空电子技术

诺思罗普-格鲁曼公司在自己的网站上吹嘘说,“精灵”B-2隐形轰炸机几乎是看不见的,因为该机的复合材料和蝙蝠形状的设计使其难以被雷达发现。然而以相同形状和材料制造的一架F-117战斗机却于1999年在巴尔干半岛上空被击落。隐形技术绝不是假的。它能缩小飞机在雷达屏幕上的信号特征。假如普通飞机在200公里以外时在雷达屏幕上形成一个光点,那么隐形飞机要到34公里时才会在雷达屏幕上显现。

问题是,雷达最终还是会发现飞机。天气也会带来问题。对B -2材料的测试工作是在很少下雨的爱德华兹空军基地开展的。但当该机在巴尔干半岛执行任务时,遭到雨淋后,用于填充复合材料外壳接缝的胶带往往会松脱,从而扩大了飞机的雷达信号特征。

  原文地址:http://www.tingroom.com/lesson/yyslhj/534033.html