Lomcevak

A Lomcovák (or incorrectly spelled Lomcevak) is a family of extreme aerobatic maneuvers where the aircraft, with almost no forward speed, rotates on chosen axes due to the gyroscopic precession and torque of the rotating propeller.

The word originates from the Czech aerobatic pilot Ladislav Bezák's mechanic at the 1958 air show in Brno, Czechoslovakia. When asked by journalists what Bezák's tumble maneuvers were, jokingly called them Lomcovaks explaining it means headache.

The expression Lomcovat is commonly used in Moravia to describe the rotating motions of one who has had one drink too many of its famous alcoholic drink slivovitz. Lomcovák is the slang name for the shot of a strong drink. This expression comes from word "lomcovat" which means to jiggle; shake violently (violently move with short moves with something, what is attached hardly - e.g. the jail grille). The etymology origin is in Lomit which means "to diffract; to divide; braking (rod)". Most likely a link to steering rod manipulation during the maneuvre.

In the 1940s Czech aerobatic pilots called this a Talířek which means a small saucer, after the horizontal rotary movement of the aircraft.

The Lomcovak is a family of freestyle maneuvers performed at airshows. It is not in the Aresti catalogue and therefore may not be flown in competition.

Lomcovaks are very disorienting but otherwise fairly gentle for the pilot. However they are highly stressful on the aircraft structure and should only be performed by aeroplanes built for aerobatics. The worst effects are on the engine mounts, crankshaft and propeller. There have been quite a few cases of major damage to these components during Lomcovaks.

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Wikipedia