The turn ( double. Renversement , also in German-speaking Switzerland so called; English stall turn , hammerhead turn or (rarely) Fieseler maneuvre ) is an aerobatic maneuver from the catalog of Aresti .
The aircraft is raised from a horizontal to a vertical attitude at high speed. The force of gravity reduces the speed; At a speed that depends on the aircraft, the rudder initiates a rotation of 180 ° around the vertical axis. The aircraft rotates almost at a standstill around its vertical axis (which at this moment is parallel to the ground). After the turn, it flies straight down and regains speed.
In powered flight, the turn is one of the aerobatic maneuvers that are easier to fly. In gliding, on the other hand, the turn is a difficult figure because there is no propeller wind and therefore, on the one hand, the point in time for initiating the turn must be met very precisely, and on the other hand, there are only very limited correction options in the fanning phase (turning around the vertical axis). With gliders, the turn can hardly be carried out properly without “pre-tensioning” (conscious pushing during the upward line).
The turn is one of the figures that are required at the aerobatic test.
Since there is no aircraft weight opposing the lift of the wings during the vertical phase of the maneuver, the flow does not break off at any point in time, even with decreasing speed: At zero g ( g-force ) lift, the stall speed is zero. Therefore, the term stall turn sometimes used in English is incorrect.