The story
The concept of creating a disk or polygonal aircraft has been around for many years and there are numerous patent applications but the first relying on the Coanda effect acting on the upper surface alone was first put forward in a paper by R. J. Collins.
Collins' invention is intended for civil UAV applications and aerial monitoring of urban areas.
A further paper described for a fully steerable and controllable air space platform accompanied by video footage of lift and attitude control. The Coanda disk concept has a number of attractive features for use in a non hostile environments, however one disadvantage is that flight control presents a heavy power over head compared to other vertical take off and landing air platforms. As a consequence, flight endurance using electric or even internal combustion engines does not compare favorably with helicopters.. Archived 13 September 2017 at the Wayback Machine To overcome this problem, a disk gas turbine engine has been specifically designed to be accommodated on a Coanda disk aircraft.
From Wikipedia’s article on GFS Projects, shared under CC BY-SA 4.0.3