London, August 14 (ANI): The smallest ever free-flying aircraft to hover and climb with flapping wings has taken off successfully without the aid of wires.
The aircraft was tested at aerospace firm Aeronvironment of Monrovia, California.
Until now, such robots have not carried their own batteries and have been guided by wires that allow them to move only up and down.
According to a report in New Scientist, Aeronvironment has released video that shows its "nano air vehicle" (NAV), which is the size of a small bird or large insect, hovering indoors without such crutches and under radio control.
"It is capable of climbing and descending vertically, flying sideways left and right, as well as forward and backward, under remote control," said the company.
Aeronvironment's flapper appears to achieve propulsion, stabilization and control all at once using its paired wings.
Pentagon's Defense Advanced Projects Research Agency (DARPA) has said it wants a 10-gram aircraft with a 7.5-centimetre wingspan that can explore caves and other hiding places, relaying GPS data and images to base.
It will need to fly at 10 metres per second and withstand 2.5-metre-per-second gusts of wind.
That goal is a long way off, but according to DARPA programme manager Todd Hylton, Aeronvironment is on the right track.
"Progress to date puts us on the path to such a vehicle," he said.
Biopropulsion researcher Michele Milano at Arizona State University in Tempe agrees that the hovering bug is a breakthrough.
But, he added that Aeronvironment faces two big challenges: boosting manoeuvrability and energy efficiency.
"Achieving manoeuvring capabilities similar to those of hummingbirds or fruit flies will be tough. For that, a deeper knowledge and understanding of the aerodynamics of unsteady flapping flight is needed,"
The NAV's endurance will also need to be upgraded. At present, it can't manage more than 20 seconds aloft. (ANI)