万花筒 2013-05-16&05-18 美X-51A破高超音速记录：6分钟冲刺5.1马赫
时间：2019-01-07 作者：英语课 分类：万花筒2013年
英语课
This was the flight of the Boeing X51A Waverrider. The company and the US military says it’s made aviation history. The unmanned craft achieved the longest ever hypersonic flights by a jet fuelled-propelling.
It hurtled alone at 5 times the speed of sound for 3 and a half minutes. It covered 213 nautical 1 miles in just over 6 minutes across the skies of California. The US Air Force says the craft was intended to demonstrate the new technology, not as a prototype for new weapons. It was the last 4 X51A craft built by Boeing. The end of the dramatic journey was a little less than glorious. It was crashed into the Pacific ocean in a controlled dive.