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.
波音公司和空中客车公司都在大肆宣扬他们最新型飞机的效率，它们的型号分别是787和A350。它们充满智慧的设计和使用的轻型复合材料当然是起到一定作用的。但是在斯坦福大学，一组由Ilan Kroo领导的研究人员建议航空公司可以采用一种更加贴近自然的方法来减少航空燃油的使用，并且这不需要它们去购买新的飞机来实现。
The answer, says Dr. Kroo, lies with birds. Since 1914, scientists have known that birds flying in formation -- a V-shape -- 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 rang increase of 71%.
Kroo博士说答案就在鸟类的身上。自从1914年来，科学家们就发现鸟类编成“V”字队型飞行时可以减少能量消耗。从鸟类翅膀上方流过的气流在翼尖后方盘旋而上，这种现象就是上升气流。其它经过上升气流的鸟在飞行时将减少空气阻力，并且只需要更小的能量就可以推动自身飞行。前加州理工学院和南加州大学的航空专家Peter Lissaman提到，一个由25只鸟组成的队型可以使它们的飞行距离增加71%。
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 assemble over Utah, assume an inverted V-formation, occasionally change places so all could have a turn in the most favourable 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.
当这些理论被应用到飞机上时，它的本质上没有太大的区别。Kroo博士和他的团队进行了一次模拟实验，如果三架客机分别从洛杉矶、旧金山和拉斯维加斯起飞，在犹他州上空会合，并编成一个倒“V”的队型，此后三架飞机间或更改位置，以便所有的飞机都轮流处在队型中的最佳位置，随后便以此规则继续飞行到伦敦。他们发现飞机少消耗了15%的燃料（与此同时二氧化碳的排放也减少了）。巡航过程中的一氧化氮的排放则下降了四分之一。
There are, of course, knots to be worked out. One consideration is safety, or at least the perception of it. Would passengers feel comfortable travelling in companion? Dr. Kroo points out that the aircraft could be separated by several nautical miles, and would not be in the intimate groupings favoured 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 Organisation has included the possibility of formation flying in a blueprint for new operational guidelines.
当然，仍然有一些关键问题需要解决。其中有一个需要考虑的事情那就是安全，或者至少说是对安全状况的感知能力。飞机结伴飞行时，乘客是否觉得舒适？Kroo博士指出飞机之间间隔几海里远，而不是保持一个被红箭之类的表演队所亲睐的紧密队型。乘客向窗外仔细看去甚至都不能发现其它的飞机。飞机间隔距离涉及到是否符合空中交通管制条例则是另一个问题，尽管国际民用航空组织的一个工作组已经将编队飞行的可能性纳入了新的操作指南蓝图中。
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.
天气状况会怎样影响使得编队飞行更加高效的气流还有待观察。在强乱流的地区，飞机的航迹消失地更快，尾流的效果也将消失。Kroo博士说这个问题是他的团队会继续研究的领域。为了获得编队飞行的好处，航空公司可能也很难去协调客机的起飞时间和目的地。相比之下货运飞机则像常规的军事飞机一样，更容易调整航班时间。
As it happens, America's armed forces are on the case already. Earlier this year the country's Defence Advanced Research Projects Agency announced plans to pay Boeing to investigate formation flight, though the programme 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 unsubstantiated. "My father was an RAF pilot and my cousin the skipper of a Lancaster lost over Berlin," he adds. So he should know.
碰巧的是，美国的武装部队已经在研究这件事情的可能性了。今年早些时候，国家国防高级研究计划局宣布将出资给波音公司来研究编队飞行，尽管该项目现在还尚未启动。有些报道提到在二战时期，有些军用飞机在低油量的情况下会编队飞行，然而Lissaman博士说这些报道是尚未被证实的，他表示：“我的父亲是英国皇家空军飞行员，而我的堂兄是一架在柏林上空失去联系的兰开斯特的机长”。因此他应该是了解情况的。