An Armada is the capoeira version of a Reverse Roundhouse kick.
After the take off, the torso stays upright and vertical, but will begin to quickly torque in order to swing the legs around and upwards.
The legs continue to swing over as the body straightens out for the landing.
A standing position and linking it in or at the end of a combo are more difficult due to the height and amount of torque needed.
A similar move is also performed in snowboarding and inline skating and is referred to as a Misty Flip.