新题型

　　本文出处：The Economist print edition;Dec 3rd 2009

　　原文标题：Copying birds may save aircraft fuel

　　BOTH Boeing and Airbus have trumpeted the efficiency of their newest aircraft, the 787 and A350 respectively. Their clever designs and lightweight composites certainly make a difference. But a group of researchers at Stanford University, led by Ilan Kroo, has suggested that airlines could take a more naturalistic approach to cutting jet-fuel use, and it would not require them to buy new aircraft。

　　第41题：【F】 因为飞机的飞行路线可以改用更具仿生效应的路径来节省燃油，而且并不需要购买新的飞机。

　　The answer, says Dr Kroo, lies with birds. Since 1914, and a seminal paper by a German researcher called Carl Wieselsberger, scientists have known that birds flying in formation—a V-shape, echelon or otherwise—expend less energy. The air flowing over a bird’s wings curls upwards behind the wingtips, a phenomenon known as upwash. Other birds flying in the upwash experience reduced drag, and spend less energy propelling themselves. Peter Lissaman, an aeronautics expert who was formerly at Caltech and the University of Southern California, has suggested that a formation of 25 birds might enjoy a range increase of 71%。

　　第42题：【T】，因为drag有阻力的意思。

　　When applied to aircraft, the principles are not substantially different. Dr Kroo and his team modeled what would happen if three passenger jets departing from Los Angeles, San Francisco and Las Vegas were to rendezvous over Utah, assume an inverted V-formation, occasionally swap places so all could have a turn in the most favorable positions, and proceed to London. They found that the aircraft consumed as much as 15% less fuel (coupled with a reduction in carbon-dioxide output). Nitrogen-oxide emissions during the cruising portions of the flight fell by around a quarter。

　　There are, of course, kinks to be worked out. One consideration is safety, or at least the perception of it. Would passengers feel comfortable traveling in convoy? Dr Kroo points out that the aircraft could be separated by several nautical miles, and would not be in the intimate groupings favored by display teams like the Red Arrows. A passenger peering out of the window might not even see the other planes. Whether the separation distances involved would satisfy air-traffic-control regulations is another matter, although a working group at the International Civil Aviation Organization has included the possibility of formation flying in a blueprint for new operational guidelines。

　　第43题：【T】，根据以上划线部分，即飞机间会相隔几海里，不会像红箭表演队(英国皇家空军特技表演队)那样间距小到令人窒息。乘客往窗外看也许都看不到另外的飞机。可以得出乘客其实不受影响。另外要注意的是，题目中的more在这里不表示比较级。

　　It remains to be seen how weather conditions affect the air flows that make formation flight more efficient. In zones of increased turbulence, the planes’ wakes will decay more quickly and the effect will diminish. Dr Kroo says this is one of the areas his team will investigate further. It might also be hard for airlines to co-ordinate the departure times and destinations of passenger aircraft in a way that would allow them to gain from formation flight. Cargo aircraft, in contrast, might be easier to reschedule, as might routine military flights。

　　第44题：【T】段首句强调“天气情况对气流的影响现在仍需观察”所以本题正确。

　　As it happens, America’s armed forces are on the case already. Earlier this year the country’s Defense Advanced Research Projects Agency announced plans to pay Boeing to investigate formation flight, though the program has yet to begin. There are reports that some military aircraft flew in formation when they were low on fuel during the Second World War, but Dr Lissaman says they are apocryphal. “My father was an RAF pilot and my cousin the skipper of a Lancaster lost over Berlin,” he adds. So he should know。

　　第45题：【F】根据but转折词，即划线部分，但Dr Lissaman称那些都是杜撰的。

　　41. Findings of the Stanford University researchers will promote the sales of new Boeing and Airbus aircraft。

　　42. The upwash experience may save propelling energy as well as reducing resistance。

　　43. Formation flight is more comfortable because passengers can not see the other planes。

　　44. The role that weather plays in formation flight has not yet been clearly defined。

　　45. It has been documented that during World War II, America’s armed forces once tried formation flight to save fuel。

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