The Swallowtail Challenge.

Apparently, swallowtail butterflies have posed a bit of a puzzle to the sort of chap that studies that sort of thing.

Butterflies actually have two pairs of wings - fore and aft, if you like.  Most butterflies have these pairs separated, to allow greater control over their flight, but swallowtail wings overlap, effectively becoming a single wing.

They are stuck with a simple up-and-down flap.  The puzzle was; where does the control come from.

It is hard to measure the forces acting on and in a live butterfly, so the researchers built a model - a small version of the hobbyists rubber-powered ornithopter, the same size and weight of a real swallowtail.

They cast replica wings from fluorocarbons and polyurethane, and set it off in front of slow-motion video cameras.

The conclusion?

The unique shape of the wing provides automatic control - the combination of flexibility of the wing and the rigidity of the veins provide a passive control and stability.

The point?

Why am I posting this here?  As a challenge: the swallowtail ornithopter was (except for the wings), very basic - wire frame and a rubber band.

How small could such an aircraft go?

How tiny could you, dear reader, build a working ornithopter?

Institute of Physics article.
(Free registration required to read it in full, if you are quick)

Picture of The Swallowtail Challenge.
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dombeef7 years ago
Here is what I made
Kiteman (author)  dombeef7 years ago
Oh, my goodness! Does it actually fly?
dombeef Kiteman7 years ago
It has a jerky motion but it can fly for about 3 to 5 feet if I wind it up to the maximum limit. That coin is a quarter for the comparison.
Kiteman (author)  dombeef7 years ago
dombeef Kiteman7 years ago
And can you feature the comment?
dombeef Kiteman7 years ago
CameronSS7 years ago
Looks like the same layout as royalestel's design, which is the same layout as the Make Weekend Project. The stick out the front of the butterfly appears to just be holding the wings still for a photo.

Translation: the instructions are already there, just make them little and make cool cutout butterfly wings.
 It looks more like Captain Molo's design
Having watched the video a few times I believe the stick out front is there to adjust the center of gravity.
Kiteman (author)  CameronSS7 years ago
There are two separate challenges:
  • Engineering the mechanism to be small, yet able to overcome friction (the swallowtail model had a very jerky motion).
  • The wings themselves - the team above cast their wings in photo-etched moulds

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