Kites flying circular patterns are well known in AWE R&D, for example Makani’s M600 looping kiteplane. KiteLab Group pioneered AWES looping-kite proof-of-concept. There has been tremendous progress and variety to how looping kites are now configured and tapped; including multi-kite formations, flygen or groundgen variants, torque or pumping PTOs, rigid or soft wings, etc.
Sample early KiteLab looping-kite videos-
http://energykitesystems.net/KiteLab/tripodtether.mpg
http://energykitesystems.net/KiteLab/wsikfwing.mpg
http://energykitesystems.net/KiteLab/eddyloop.mpg
http://energykitesystems.net/KiteLab/deltarch.mpeg