Many thanksI've been busy working on other things lately, but thought about Owlet again today. I thought it a shame that I wasn't doing anything with it, and recalled that someone had at one point expressed an interest in an stl for it. Why not? Maybe someone else can find something interesting to do with this.
-but very economical=1 kg bird can fly continously 10000 km on the 0.5 kg fat,birds flying
That is some really exciting stuff and exactly why I am following this thread. I intend to put a couple of wings like that on my aquatic pondhopper.For anyone interested, I've finally cracked the problem of stringing feathers such that they can spread and fold smoothly while also being load-bearing. As suspected back in post #99, I was doing something dumb. Notice that the feathers near the wrist now attach higher up on the bones, rather than down in the joint. This allows the secondaries to lay much more nicely over the primaries, without any of them getting dragged underneath like before. I've also eliminated the metal attachment loops, saving some weight and work. Everything is done with threads passing through holes in the bones and feathers.
The next trick was to shift the secondary hold-down lines over by one feather compared to what I've tried in the past and jammed up when folding. S1's hold-down line attaches to the bone at S2's hole, S2's hold-down attaches to S3's hole, and so on. This way the feathers are pulled farther down as the wing is extended, and relaxed as it folds so the secondaries can slide up over the primaries. The motion is so natural, I suspect the ligaments on real wings are arranged similarly. I could probably see it if I pick apart another real wing, now that I know what to look for. The answers are all there if you just have the eyes to see
The feathers near the elbow still stick up a little bit, and I'm pretty sure that's due to the shape of the bone itself rather than the stringing. I'm making some modifications to the 3D model to curve it down further at the elbow. I also need to do another round of feather fabrication for the underside coverts and the alula feathers. Or perhaps retire this wing and make a full feather set for a different species. Canada goose may be a good model for human flight, but was a terrible choice for R&D due to the ridiculous number of secondary feathers