The incredible agility of the common house or fruit fly puts every drone and robot to shame, but devices inspired by them are beginning to catch up. A new four-winged flapping robot not only successfully imitates the fruit fly’s hyper-agile flying method, but can travel for up to a kilometer before running out of juice.

Robotics researchers at the Delft University of Technology wanted to create a flying platform that could imitate and test theories on how insects fly the way they do, but without tethers or non-animal propulsion like propellers.

It’s not just that they want a cool robot: The way insects respond to things like gusts of wind or an imminent slapping hand demonstrate incredible reaction times and control feedback, things that could inform autonomous craft like drones or even small airplanes. Wouldn’t it be nice to know your jet could autonomously and smoothly dodge a lightning bolt?

The trouble is that when you get much bigger than an insect, that method of flying doesn’t always work any more due to the differences in mass, drag and so on. As the researchers put it in their paper, which made the cover of Science:

Because of technological challenges arising from stringent weight and size restrictions, most existing designs cannot match the flight performance of their biological counterparts; they lack the necessary agility, sufficient power to take off, or sufficient energy to fly for more than a minute.

Not only that, but tiny robots like the Robobee require a wired power connection, and other tiny flapping craft require manual piloting. Can’t have that! So rather than slavishly imitate the biology of a single animal, the team focused on how to achieve similar flight characteristics at a realistic scale.

The four-winged, tailless style of their creation, the DelFly Nimble, is novel but evidently effective. Their robot can go 7 meters per second, or about 15 MPH, hover in place or perform all kinds of extreme motions like dives and rolls smoothly. It’s no joke doing that using rotors with continuous thrust, let alone via coordinated wing movement. You can see it perform a few more capers in the video here.

Perhaps most amazing is its range; the robot can travel for a kilometer on a single charge. That sort of spec is the kind that military R&D directors love to hear about.

But the DelFly Nimble is already producing interesting scientific data, as lead researcher Matěj Karásek explains:

In contrast to animal experiments, we were in full control of what was happening in the robot’s ‘brain.’ This allowed us to identify and describe a new passive aerodynamic mechanism that assists the flies, but possibly also other flying animals, in steering their direction throughout these rapid banked turns.

Development is continuing, and no doubt biologists and three-letter agencies have tendered letters of interest to the Dutch inventors.