Whirligig beetle Could Inspire Boat Design

[GordMay]

Fastest swimming insect could inspire uncrewed boat designs

Whirligig beetles, the world's fastest-swimming insect, achieve surprising speeds, by employing a strategy shared by fast-swimming marine mammals and waterfowl, according to a new study [1] that rewrites previous explanations of the physics involved.

The centimeter-long beetles can reach a peak acceleration of 100 meters per second, and a top velocity of 100 body lengths per second [or one meter per second].

Not only do the results explain the whirligig’s Olympian speeds, but they also offer valuable insights, for bio-inspired designers, of near-surface water robots, and un-crewed boats.

Until now, researchers have believed that whirligigs attain their impressive speeds, using a propulsion system called drag-based thrust.

This type of thrust requires the insect’s legs to move faster than the swimming speed, in order for the legs to generate any thrust.

For the whirligig beetle to achieve such fast swimming speeds, its legs would need to push against the water at unrealistic speeds.

In fact, fast-swimming marine mammals [& waterfowl] tend to forgo drag-based thrust, in favour of lift-based thrust, another propulsion system.

Lift-based thrust works like a propeller, where the thrusting motion is perpendicular to the water surface, eliminating drag. and allowing for more efficient momentum, capable of greater speed.
Lift-based thrust has previously been identified in large-scale organisms, such as whales, dolphins, and sea lions.

The U.S. Navy has been developing uncrewed boats, as traditional ship design is constrained by the need to make boats hospitable to a crew. By eliminating a crew, boats can be much smaller and more flexible.
The small size, ship-like shape, and lift-generating propulsion mechanism of whirligigs, translate well, to inform robotic ship designs.

The finding was described, in a study [1] published Jan. 8, in the journal ‘Current Biology’.

More about ➥ https://news.cornell.edu/stories/202...d-boat-designs

[1] “Whirligig beetle uses lift-based thrust for fastest insect swimming” ~ by Yukun Sun, Jena Shields, & Chris Roh
➥ https://www.cell.com/current-biology...showall%3Dtrue