A new "Bat Bot" drone could fly circles around its rivals as its flexible flying style may help navigate disaster sites.
The prototype, which weighs in at just 85g, mimics the unique way bats fly and could do better job of getting into disaster sites or scoping out construction zones than bulky drones with spinning rotors, according to a study in the Science Robotics journal.
It would have been ideal for going inside the damaged Fukushima nuclear plant in Japan, said study co-author Seth Hutchinson, an engineering professor at the University of Illinois.
The bat robot flaps its wings for better aerial manoeuvres, glides to save energy and dive bombs when needed.
Eventually, the researchers hope to have it perch upside down like the real thing, but that will have to wait for the robot's sequel.
The Bat Bot has nine joints and measures slightly less than 20cm from head to tail with its super-thin membrane wings spanning about 45cm.
The flexible flapping - as much as 10 times per second - acts "like a big power amplifier," Hutchinson said on Wednesday.
The researchers still need to add cameras, build more drones and get permission from federal agencies to fly them, but Hutchinson said these bat robots could be flying around work sites and disaster zones within five years.
It's already taken three years and cost $US1.5 million ($A2 million), including a team of experts from Brown University who studied bat flight, Hutchinson said.
Outside robotics experts were impressed, but cautious.
Smaller fixed-wing drones have problems with manoeuvrability and four rotors are not efficient, so a bat-inspired design is "a very intriguing line of research," University of Pennsylvania engineering professor Vijay Kumar said.
However, he noted, "it is too early to tell if these designs will actually be superior."
