 The twin tail layout helps in maneuvers at high angle of attack (AoA) while reducing the height of the aircraft to fit within the limited roof clearance of hangars aboard aircraft carriers.Two triangular shaped retractable surfaces, called glove vanes, were originally mounted in the forward part of the wing glove, and could be automatically extended by the flight control system at high Mach numbers.They were used to generate additional lift (force) ahead of the aircraft's center of gravity, thus helping to compensate for mach tuck at supersonic speeds.