Passage 1
Questions 11—15 are based on the following passage.
Plane wings are traditionally strong and thick but a team of researchers led by NASA hascreated a flexible wing that morphs(变形)as it flies. The new wing is constructed fromthousands of units that fit together and function in a similar way to a bird's wing, says NASAresearch engineer, Nick Cramer.
"Something like an eagle will lock its joints in while it's cruising, and then it adjusts itswings to a more suitable shape for its cruising, and then when it wants to do a more aggressivemove it'll unlock its shoulder. That's a similar response to what we're doing here,"he said.
The Boeing 787 Dreamliner is constructed from body parts that are so large, so they requireoutsize molds(模具)to create them. The same applies to the Airbus A380."The cost ofinfrastructure(基础设施)that the business needs to invest to build these planes is prettyextraordinary," said Kenneth Cheung, a NASA research scientist."So what we're doing withthese projects is trying to reduce all of that, so that you could have the same sort of performancein terms of the materials but be able to manufacture it without setting up all of the infrastructurethat's currently required."
The new wings are created by putting fiber reinforced polyetherimide into a 3D mold tocreate each part, which locks together in a process that could eventually be carried out byassembly robots. The new structure can also be easily packed down to allow transport, which also makes it potentially the ideal package for another purpose — to send into space.
While the idea of cheaper, more flexible planes could be appealing to the commercial aviationindustry,there are major obstacles to overcome. That demands time, research and money.“Ifyou want to revolutionize the traditional manufacturing process of the aerospace industry,youhave to have a really good reason,"Cramer said."So your performance gain has to be significantenough to justify that. It's not about whether it's practicable; it's about whether it's financiallymarketable."