XP831 This aircraft is the first prototype of the Hawker P1127 - the XP831 - which proved the practicability of vertical takeoff and landing (VTOL), and led to the Harrier Jump Jet.是什么意思_XP831 This aircraft is the first prototype of the Hawker P1127 - the XP831 - which proved the practicability of vertical takeoff and landing (VTOL), and led to the Harrier Jump Jet.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句