Immelmann turn

(military, aviation, archaic) A WWI-era fighter pilot maneuver resembling the aerobatic wingover or hammer-head turn, originally developed by Max Immelmann.

(aviation) The roll-off-the-top aerobatic maneuver, where an aircraft in upright level flight pulls up through one-half of an inside loop until in level inverted flight and then rolls upright, ending up in upright level flight in the opposite direction at a higher altitude; a reverse split S.