My proposal did not include springs.
-in youth we have bad L/D hanggliders...for longering fly time/distance
we was "pumping" wing via trapetze.= weavy trajectory needs smaller energy as strait one !
Call 1-800-ROGALLO :) IIRC that situation is exactly what the original flexwing was designed for. And for GOODNESS sakes, how is the MOSI coming ???? :) .. hoping to come up with a feather weight wing with better glide than a parafoil or an old "standard" Rogallo (invented by John Dickenson)...
=trajectory for JANTAR glider...(circa 100 km/h)