Bob Moore schrieb:

Just point us at the definition.

Barrel roll
From Wikipedia, the free encyclopedia
....

Wikipedia is not more reliable than you and me talking over a beer. That
said:


"... a 360 degrees roll around the aircraft's zero lift axis, producing
positive g throughout, starting and finishing at the same altitude in
horizontal flight and parallel to the competition axis. For a perfect
result the rate of roll should be constant, although this is not a
universal requirement.

.... a mixture of a roll and a loop ...

The amount of g pulled, the extent (below 90 degrees) of displacement of
the fuselage axis, and the diameter and shape of the "tunnel" will
depend on he aircraft's speed and rate of roll: they do not form part of
the judging criteria."

Source: Eric Muller in "Flight Unlimited".