As occurred in many ways in the first decades of 1900s, the triangle control frame (TCF) (at least used cable-stayed with pilot hung from tether to keel behind TCF in 1908 in a hang glider as we often use today in hang gliders and microlights) emerged in some builds, one of which is shown in November issue of Popular Mechanics, 1961. Popular Mechanics has enjoyed readership around the world.

See article:
I flew the Pterodactyl Flex-Wing  
The Hottest Thing in Aviation
by Lou Everett, test pilot for Ryan Aeronautical Company

This publication was at about the moment the other program of hung-pilot gliders was taking place in the Paresev  program, where build orders were issues in December 1961 and completed in a month or so under Paul Bikle and Charles Richards. 

http://tinyurl.com/FlexWingNov1961PopMech