The F-35B short takeoff/vertical landing (STOVL) variant is the world’s first supersonic STOVL stealth aircraft. It is designed to operate from austere bases and a range of air-capable ships near front-line combat zones. It can also take off and land conventionally from longer runways on major bases. The F-35B STOVL operation is made possible through the Rolls-Royce patented shaft-driven LiftFanÂ® propulsion system and an engine that can swivel 90 degrees when in short takeoff/vertical landing mode. Because of the LiftFanÂ®, the STOVL variant has smaller internal weapon bay and less internal fuel capacity than the F-35A. It uses the probe and drogue method of aerial refueling.