Recently, a large four-engine UAV independently developed by China with complete intellectual property rights made its first flight in Sichuan. It is understood that the "Twin-tailed Scorpion D" that successfully made its first flight this time is the world's first large-scale four-engine, multi-purpose, medium-altitude long-endurance fixed-wing UAV system. The aircraft has a wingspan of 20 meters, a length of 10.5 meters, a height of 3.1 meters, a maximum take-off weight of 4.35 tons, a maximum payload of 1.5 tons, and a maximum loading space of 5 cubic meters.