Closed wing
AIRCRAFT WING CONFIGURATION WITH A NON-PLANAR, CONTINUOUS SURFACE WING
Ring Wing; Closed wings; Ring wings; Annular wings; Annular wing; Boxplane; Joined wing; Nasa ring wing; Box wing; Ring wing
A closed wing is a wing that effectively has two main planes which merge at their ends so that there are no conventional wing tips. Closed wing designs include the annular wing (commonly known as the cylindrical or ring wing), the joined wing, the box wing and spiroid tip devices.