It's a bird… It's a plane… It's RoboSwift!

The world's first aircraft that looks and flies like a bird, will be flown in India in March 2008

Nine Dutch Aerospace engineering students from the Delft University of Technology took help from the Department of Experimental Zoology of Wageningen University, to come up with a micro airplane that manoeuvres by changing the shape and position of its wings. The common swift, one of nature's most efficient flyers, was the inspiration behind the device. That's why they've called it RoboSwift.

RoboSwift steers by sweeping one wing back, while keeping the other extended, allowing it to make very sharp turns. Wing geometry as well as wing surface area can be adjusted continuously, making RoboSwift so manoeuvrable that it can actually fly with a group of swifts.

Flying in India
RoboSwift will be seen in action at the First American-Asian Micro Air Vehicle competition in India in March 2008, in which the student team will enter three RoboSwifts.

RoboSwift has a wingspan of 50 cm span weighs just 80 g. It even looks like a common swift, and can go undetected while using three micro cameras to perform surveillance on vehicles and people on the ground. It can even be used to observe swifts in flight, enabling research in zoology.

It is powered by lithium-polymer batteries that drive an electric motor and a propeller, which folds back during gliding to minimise air drag. It can follow a group of swifts up to 20 minutes, or perform ground surveillance for up to one hour on a single charge.

The RoboSwift team presented the design at the yearly Design Synthesis symposium at TU Delft. The team will build the high-tech micro airplane in the coming months and is expected to fly it in January 2008.

Wings that morph
The unique morph-wing design is taken from the swift. The RoboSwift's wings can be swept back in flight by folding feathers over each other, which changes the wing shape and reduces the wing surface area. While it steers by morphing its wings, this feature also enables it to be highly manoeuvrable at very high and very low speeds, just like the swift.

RoboSwift's wing uses only four feathers, much less than the bird uses, which provide the wing with sufficient morphing capacity. Sweeping one wing back further than the other creates a difference in lift on the wings that is used to roll and turn the micro plane in the air.

Learning from nature
The project was based on research performed by the students' tutor David Lentink, who published a study about the swift's flight characteristics in the April 2007 issue of Nature. During its life, a common swift flies more than five times the distance to the Moon and back. Lentink found the swift continuously morphs its wings according to flight conditions, for better efficiency and manoeuvrability.

A revolutionary design
Airplanes do not fly as well as birds in terms of performance and efficiency, partly because their wings are fixed. With variable wings, birds can more easily take advantage of different conditions encountered during flight, increasing their efficiency and agility up to a factor of three.

A few military aircraft like the F14 Tomcat and the English-German Tornado, have 'swing wings' but cannot significantly reduce the surface area of the wing, and lose the benefits made possible by morphing. No known aircraft steers by changing wing shape.