Hungry hawkmoths are helping scientists improve drone flight capabilities

Understanding the nuances of insect flight has enormous practical applications for improving drone flight capabilities

by GrrlScientist for Forbes | @GrrlScientist

Original title: “Not Even A Cannonball Can Shoot A Hungry Hawkmoth Out Of The Sky”

A hawkmoth (Family: Sphingidae) hovers at a flower as it sips nectar through a proboscis that is longer than its body.
(Credit: bioGraphic)

The first time I ever saw a hawkmoth in the wild, I mistook it for a very small hummingbird. What sort of hummingbird could it be? I wondered as I reached for my binoculars.

Then I realized … oh, oops. Never mind!

When you’re out roaming through a field of wildflowers or a garden flowerbed, look carefully and you too may spot a hawkmoth sipping nectar as it hovers in front of a flower in the dying sunlight.

Hawkmoths are members of the Sphingidae family of moths, which are amongst the largest flying insects in the world. These moths are extraordinary: even when it’s breezy, these large insects can hover in front of a flower and delicately extend their proboscis, which is at least as long as their body, to reach nectar deep inside a blossom.

“It’s like trying to drink from a soda can with a six-foot-long straw,” said Tyson Hedrick, a biology professor who studies animal locomotion and flight at The University of North Carolina at Chapel Hill.

In fact, hawkmoths remain surprisingly stable in flight, and can recover extremely quickly if they are knocked off balance midflight by some sort of disturbance. How do they do it? Professor Hedrick and his collaborators are asking this very question using a variety of high-tech methods, including 3D-printed “moth cannons” that shoot tiny copper cannonballs at the resilient insects whilst they sip nectar — all under the unblinking eyes of three high-speed video cameras that each shoot 1,000 frames per second. Hawkmoth wings flap 30–50 times per second, so Professor Hedrick and his team capture roughly 40 frames per hawkmoth wingflap with each camera. The resulting 3D-flight videos are analyzed to identify how the moths recover and stabilize their hovering flight (ref).

Not only is this research interesting, but Professor Hedrick’s biomechanical studies have important applications for improving flight stability of minidrones and a variety of small human-made wing-flapping robots and other gadgets that have not even been invented yet.

“If you want to build a small flapping-wing vehicle, what are the requirements to not just power it, but to make it stable in an environment that is not very friendly to small flying things?” Professor Hedrick said.

“[Hawkmoths] are teaching us general lessons in how this stability problem has been solved by evolution.”

Video courtesy of bioGraphic.

Read more about this:

Chao Zhang, Tyson L. Hedrick, and Rajat Mittal (2018). An Integrated Study of the Aeromechanics of Hovering Flight in Perturbed Flows, AIAA Journal | doi:10.2514/1.J056583

Originally published at Forbes on 31 August 2018.