China has unveiled a tail-sitter drone – which takes off and lands on its tail like a rocket – during a disaster rescue drill, according to state media.In its debut, the new unmanned aerial vehicle’s sensors and cameras were put to the test for reconnaissance and real-time situational awareness operations in a mountainous region of Sichuan province, the official Science and Technology Daily reported on Tuesday.The drone’s Wenyao intelligent control system was also on show, with the drill...