The Lufbery Circle, or Lufbery Wheel, also spelled “Lufberry” or “Luffberry”, is a defensive air combat tactic first used during World War I.
While its name derives from the name of Raoul Lufbery, the leading fighter ace of the Lafayette Escadrille, he did not invent the tactic; how it acquired this name is not known, although it may be from his popularization of it among the incoming U.S. pilots he trained. In non-American sources it is in fact usually referred to simply as a “defensive circle”.
Mostly in World War II literature, a Lufbery Circle can be used to refer to any turning engagement between aircraft, i.e. what is more properly known as the Turn Fight in air combat tactics.
In modern discussions of air-to-air combat tactics, a “Lufbery” generally refers to any prolonged horizontal engagement between two fighters with neither gaining the advantage. This frequently occurs when both fighters have descended to low altitude and have insufficient energy for further vertical maneuvering, thus restricting the fight to the horizontal plane. Such a fight assumes that one fighter does not have a significant turn rate advantage and is thus locked in a seemingly endless tail chase.
Such a fight is said to wind up in a Lufbery or has said to have “Luffed out”; this being a generally undesirable circumstance as neither fighter is able to conclude the fight nor leave without potentially exposing himself to attack by the remaining fighter.