Commercial planes could soon mimic migrating birds by traveling together, with one airliner following close behind the other to gain some free lift. European manufacturing giant Airbus says this project, called fello’ fly, could reduce the follower aircraft’s fuel requirements by up to 10 percent per trip.
Fello’ fly was inspired by the way some birds, typically geese, often fly in formation (编队) to save energy. Like a bird, a moving airplane leaves a wake of disturbed air behind as its wings produce swirling vortices (气旋). These vortices move in a circular motion and expand outward until they disappear, creating an updraft (上升气流) around the wake. If a second aircraft follows the leader at a specific distance and slightly away from the center of the wake, this updraft provides extra lift.
Such a boost allows the follower to cut down on engine thrust, fuel use and emissions. But to reap these benefits, airliners have to position themselves carefully: if the follower gets too close to the center of the leader’s path, the vortices will actually push it downward instead of up.
Aircraft flying so close would need to coordinate (协调) carefully to prevent accidents, and this coordination would need to start on the ground. Airline pilot David Mrak, who is not involved in the fello’fly project, says challenges would likely include setting rules of engagement between the two planes, deciding on the role of air traffic controllers, maintaining communication between all parties involved, creating plans to deal with emergency situations or bad weather, and splitting the economic benefits.
Although the minimal separation might sound potentially dangerous, Mrak suggests that operating planes so near each other may not be out of the question. “As pilots, we undergo extensive training,” he says. “Flying aircraft in formation is a matter of proper training procedures.”
Mrak estimates that if the system works, “it could potentially save the airlines thousands of pounds of fuel per transatlantic trip.” And according to Airbus, every metric ton of fuel saved means roughly three metric tons less carbon dioxide emitted.
12. Which one of the following is closest in meaning to the underlined word “mimic”?
A.support | B.imitate | C.approach | D.discover |
13. Why did Airbus try to develop fello’ fly?
A.Because it can help save fuel for the two aircraft. |
B.Because it can eliminate accidents caused by birds. |
C.Because it can improve air safety for passengers. |
D.Because it can reduce greenhouse gas emissions. |
14. Which of the following is not a challenge posed to this project?
A.maintaining an appropriate distance between the two flights |
B.figuring out how to handle emergency situations |
C.deciding on the proper height of the follower flight |
D.coordinating communication between all sides |
15. What is the pilot Mrak’s attitude toward fello’ fly?
A.Disapproving. | B.Skeptical. | C.Optimistic. | D.Uninterested. |