Palm-Sized Spinning Drone Blurs at 25 Revolutions Per Second but Remains Audible and Limited to Hover

A drone developed at Northwestern University in Illinois spins at 25 revolutions per second to reduce its visibility to a faint haze against matching backgrounds. @NewScientist reported that the craft, called Phantom Twist, uses a single-motor design in which every component moves in continuous circles so that none remain fixed in the observer's view.

Emma Alexander and her colleagues created the drone through an automated three-stage process.

An initial AI produced millions of candidate designs and narrowed them to roughly 20,000 that could theoretically fly. A second AI then adjusted component positions to minimize average visibility from all angles, while a third model simulated human sight to test each design against varied backgrounds. The final layout spreads parts so they never overlap visually during rotation.

The finished drone fits in a palm and weighs 30 grams. Its structure consists of black carbon-fibre rods. Alexander said the motion blur turns mechanical components into a slight haze that an inattentive observer might miss as a change in environmental brightness.

David Whitaker of Cardiff University noted that the rotation speed causes the visual system to merge the drone's parts with the background rather than render it fully invisible. Peter Lee of the University of Portsmouth said the approach has military potential but is limited by its spindly construction, which restricts added sensors or payloads and makes rapid steering difficult.

The drone can currently maintain only a steady hover and remains audible.