So, here is what turned into a very "deep dive" project. After the 2010 WSMC (World Championships), to develop a folding flying wing glider to fit into a very light 2" diameter FAI type body tube (I chose 2" to have a decent wing chord).
The concept was not new, but the flop-wing method for a flying wing sort of was. Had terrible yaw stability problems (as in no yaw stability) til I added half-round rudder tips, problem solved. Had a bit of a flaky glide trim though, a bit of dutch roll and glide smoothly one moment and bobble a bit too easily from a minor air current.
The wing fold method worked very well, but this was not the deep dive part.
THIS was, using the wing fold tech for a "conventional" glider, 36" span:
To fit into a 2" tube, the fuselage had to fold in 3 places, plus the horizontal stab rotate 90 degrees, plus the offset rudder to fold flat. It was a "Eureka" moment when I stopped thinking of folding the fuselage vertically (pitch axis), with all sorts of complications, to horizontally, which solved so many things.
The whole fuselage and tail, sandwiched between the folded wings.
There are reasons why I kept the project under wraps at the time, and then did not end up using them after 2012 (main thing is the FAI rules changed S4 into "Rocket Glide" after 2012, and a bit risky for NAR contest flying).
Much more info, and link to a video about the project is here:
https://tinyurl.com/n9xwf5nv