Researchers Turn to 3D Printing and a Unique Flying Fish to Improve the Design of Tandem Wing Airplanes

Biomimicry, according to the Biomimicry Institute, is the search for sustainable solutions to human problems by mimicking solutions that are already found in nature. This practice has been coupled with 3D printing technology multiple times, from 3D printed dresses inspired by nature and mathematics and using a 3D printed dog nose to make better bomb detection equipment to 3D printed armor based on fish scales and studying a 3D printed salamander to help amputees and paraplegics. Researchers at Tokai University in Japan are currently studying a specific type of flying fish – the ribbon halfbeak – to come up with a better design for a specific type of airplane.

The ribbon halfbeak species can glide above the sea surface, but they differ from real flying fish in that they don’t have hind wing fins, which are typically necessary for any sustained above-water flight.

“Investigating the design of ribbon halfbeak could provide useful information for the optimal design of tandem wing airplanes,” said Dr. Yoshinobu Inada, with the university’s Department of Aeronautics and Astronautics Aerospace.

“Ribbon halfbeak fly above the water surface to evade large carnivorous fish and dolphins. Water is about a thousand times denser than air, so flying through the air is a really practical way to evade predators.”

Until now, there was not much information available about how the flying ribbon halfbeak fish actually took flight; in fact, it seems that all anyone knew was that its flying ability differed greatly from other flying fish. But thanks to the Tokai University research, scientists now know a lot more about this flying fish’s unique ability to glide right over the surface of the water.

Dr. Yoshinobu Inada [Image: Tokai University]

“Other flying fish, including the Japanese flying fish, have large pectoral fins that act as wings during flight and large pelvic fins that are used as horizontal tail wings, like those on airplanes. However, the ribbon halfbeak lacks these large pelvic tail wings. Amazingly, they solve this problem by rotating their rear body by 90 degrees and use their wide dorsal and anal fins as a horizontal tail wing.,” explained Dr. Inada.”Other related fish species are also able to jump and fly over the sea surface, but only halfbeak twist their bodies for flight. This is a really unique behaviour.”

Just imagine – a fish, essentially doing the Twist, to escape predators! According to study collaborator Junji Yonezawa, the ribbon halfbeak’s unique ‘flight’ behavior adaption could have progressed due to the “evolutionary selective pressures” the fish faced, which differed from other flying fish species.

Yonezawa said, “It has the largest number of vertebrae among Japanese halfbeaks, which means that it is able to twist the rear half of its body by a whole quarter-turn.”

This behavior adaption brings us to the tandem wing airplane, which is essentially the machine equivalent of the ribbon halfbeak. Tandem wing airplanes fly more efficiently than traditional aircraft, but they suffer a major issue in the form of downwash from the main wing onto the hind wing.

But these unique ‘flying’ fish have a solution to the problem that plagues tandem wing airplanes. In addition to twisting their bodies to actually make horizontal tail wings that allow them to fly, the Tokai University research team also discovered that the ribbon halfbeak are able to lower the effect of downwash on their tail wings, just by lifting their rear body up above their main pectoral wings.

“This has a positive effect on improving the lift and flight performance of the fish,” explained Dr. Inada.

Dr. Inada 3D printed a model that closely resembles a real ribbon halfbeak fish, and then analyzed its flight performance to get the fascinating results. He flew the 3D printed model in a wind tunnel, testing out various tail wing positions to determine how the fish was able to lower downwash, and therefore help optimize the design of tandem wing airplanes. This isn’t the first time animal studies and 3D printing technology have combined to help researchers improve flight, and I’m certain that it won’t be the last. Discuss in the Flying Fish forum at 3DPB.com.

[Source: PhysOrg]