I call this an early model because I'm just learning how to make solidworks animate this type of shape change. It's a notional model still, and the only thing you should take from this animation is that it must be made of rubber to do what the central spar is asking of it.
My current thinking is to try for a single curved spar with simple bearings at the ribs. Without a sliding interface between spar and rib, the airfoil is going to swing forward and back as it flaps. Ill discuss ways to cope with that soon. I'm letting go for the moment the concept of storing energy in the spar, and assuming for now that the spar is going to be far too stiff for that, so I need to learn how to deal with fore and aft flapping that goes with the kind we want. (That is, explore it for a bit before reverting to the twin opposing spars I animated earlier.). Having a single spar and less mechanism is worth seeing if it's possible to cope with its weirdness.
All this leads to the first major riddle to this: how to make a rigid skin adapt to complex curvatures. Not njust flap and twist now, but add reaching fore and aft. One effort I found on the net talked to 2d stretchy fabrics, but really, in order to aim high, the goal needs to start with a laminar flow airfoil, and compromise as necessary, which is likely.
Laminar flow will depend on surface smoothness and a viable airfoil no matter where you take a cross section of the wing.
That last qualifier will make sense on the next post.
