A tetropter on the verge of being snapped up by a tetrapterate
I turned to the world of 'micro air vehicles' for proof, but had to end the post with a question, as I could not find solid proof that a similar flight mechanism had indeed been invented.
Luckily, I can now report that there was indeed such a flying vehicle: the Mentor, and it flew in 2002! I emailed Roy Kornbluh (see the previous post), and he was kind enough to confirm that each of the Mentor's four wings clapped against both of its neighbours. Moreover, he directed me to a website with footage of the vehicle in flight. If you want to see it at its original place, you can find it here.
But you can also simply admire it here:
So the radial flight principle has been proven!
That does not mean that tetropters must exist on other planets. But my hypothesis is that they could, and that their mode of flying makes sense depending on what you start with. Perhaps ancestry is the simpleanswer to the question what determines whether evolution produces radial or bilateral flying body plans. Animals with bilateral symmetry that take to the air will probably end up with bilateral wings. All animal groups that evolved flight on Earth (insects, pterosaurs, bats and birds) started with a bilateral body plan in the first place. But if animals such as starfishes had gone for a more active mode of life, and had made it to land as well, perhaps their descendants would have made it into the air. If so, they would have started with a radial body plan. If evolution had taken this course, perhaps there would be animals with radial flight on Earth right now. For now, it's just machines.