A small robotic aircraft powered by rotating “paddle-wheel” wings could yet rule the skies, if renewed interest in an antique design bears fruit.

Several international research groups are working on prototype “cyclogyros”, a design first proposed more than 100 years ago.

A cyclogyro flies using “cycloidal propellers” – several wings positioned around the edge of a rotating cylindrical framework, a bit like a paddle-wheel. As each wing rotates, its blades move through the air generating lift and thrust.

And, since each wing rotates through a full circle, altering the angle of the individual blades can pull the aircraft forwards, backwards and down as well up. The maneuverability that cycloidal propellers could offer provides benefits over more established flying methods.

Although no cyclogyro has yet flown without being tethered, its proponents say the design could prove more efficient and maneuverable than helicopters at small scales. A team of Singapore researchers is leading the race to construct a working cyclogyro with a prototype that hovers on the end of a line.

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