Ultralight(超轻型的) airplanes are a recent development in aviation that provide what aviation enthusiasts have long been seeking: an inexpensive airplane that is easy to fly. The ultralight plane was born of the marriage of the hang glider and the go-kart(微型单座赛车) engine around 1974, when John Moody mounted a 12-horsepower go-kart engine on his Icarus Ⅱ hang glider.
Today’s ultralights are not just hang gliders with engines; they are" air recreation vehicles". Modem ultralight planes use snowmobile(雪地机动车)engines that let them cruise at about 50 miles per hour, climb at about 500 feet per minute, and carry combined payloads of pilot and fuel up to about 200 pounds, which is about equal to an ultralight plane’s weight when empty. More than ten thousand ultralight planes were sold last year at prices ranging from $ 2,800 to $ 7,000. But the main reason for the increasing popularity of these aircraft is not that they are inexpensive, but that they are fun to fly.
The modern ultralight plane would look very familiar to the earliest pioneers of aviation. Otto Lilienthal made more than 2000 flights in Germany in the 1890’s in what were actually hang gliders. Octave Chanute designed and built many early hang gliders. Augustus Herring, Chanute’s assistam, used these gliders as models for a glider that he built for him self. On this glider, Herring installed a compressed-air motor and flew 267 feet in 1898. The Wright brothers' Flyer was the grandfather of today’s ultralight plane. The pilot sat right out in the open, just as in modem ultralights, and used con trois that were much the same as those used in today's machines.
Though most ultralight planes are used for pleasure flying, some are also used for crop dusting, aerial photography, and even military observation service. The likelihood is that further uses will be found for ultralight planes, but their greatest use will continue to be as air recreational vehicles.
The author seems to feel that ultralight airplanes are ______.
A.a toy for the rich
B.nothing but hang gliders
C.a new development that meets the needs of aviation enthusiasts
D.the most important development in aviation since the Wright brothers' Flyer
第1题
A.规模收益不变
B.规模收益递减
C.规模收益递增
D.不能确定
第2题
A.应当扩大雇工规模
B.收益小于成本
C.缩减现有雇工规模
D.收益大于成本
E.应当维持现有雇工规模
第5题
A.规模收益递增
B.规模收益递减
C.规模收益不变
D.无法判断
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