Flapping hummingbird
One of the coolest birds has to be the hummingbird, with it flapping it’s wings quickly back and forth, rather than up and down. I tried to recreate that mechanism with a single rotational input. The result is this model, it might look a bit complicated, but it’s super easy to assemble. Just turn “handle” on the back and it'll flap it's wings, direction doesnt matter.
Importantly a 3mmx20-28mm screw is needed for this. (you can try and print a 2.9 mm rod, but I can’t guarantee it’ll work, but an STL for it is included.)
Depending on the printer quality, you might want to go for the “tight” versions of things if the joints are too loose, since they have smaller tolerances.
Printables:
The rotation-base is printed with very low tolerance, so some parts of it may have stuck together, so if it doesn’t move easily on it's own, you can just use force and it should loosen up.
assembly:
1. Assemble two wing joints using the inner joints, outer joints and wing joints like seen below, importantly make sure 1 is “inverted”:
2. add the wing-lock and joint-lock to the wings joints:
3. attach the wing joints and arm crank to the rotation base as seen below:
4. drop in the screw through all the holes and make sure the mechanism functions properly as seen below:
5. insert the turning rod into the bird-body and push in the “gear-in”. This is a little hard, but helps if you hold the gear against the “wall” and then guide it unto the rod:
6. Insert the “rotation-gear” in the bottom of the “rotation-base” and then "place down the entire flapping assembly on top, you should be able to wiggle it completely into place and then make sure the mechanism still works:
7. Insert the “beak” into the hole in your chosen bird head, you might have to clean the bottom, since a trim was needed to print it:
8. Attach the head to the bird-body, it might require some force:
9. add the bottom connectors to the “bird-bot” they are a tight fit, so getting them in partly and then pressing against a hard surface like a surface works:
10. Attach the bottom to the main body:
11. Add the feet and tail.
12. Attach the wings, make sure they are all the way "in". And you are done! it should work smoothly.