This might be what you're referring to, but Tom Stanton built a swashplateless 4 axis R/C helicopter (albeit not with toroidal blades) based on this principle:

This might be what you're referring to, but Tom Stanton built a swashplateless 4 axis R/C helicopter (albeit not with toroidal blades) based on this principle: https://youtu.be/d80oXSCcHTk https://youtu.be/d80oXSCcHTk