further to dg800
the early Rogallo hang-gliders were invented in USA an English aeromodeller of my aquaintance experimented with some large bamboo poles and Ex-War-Department fabric. His eventual practical design was sold in kit-form through adverts in "Exchange and Mart" - best described as a paper predecessor to "fleabay".
Some time down the line, the business became "Skyhook" and produced many aircraft.
The owner was Len Gabriels,- A keen dinghy sailor and great orator, he once gave a lecture explaining just how much an inch of bilge water would degrade a dinghy's performance.
and, yes, he said the regulators were so hidebound that the innovators could run rings around them. Tales of early powered hang-glider experiments were enthralling. great bloke,deserved his success. and most of it self-taught from public library.