Scientists develop a drone that spins so fast it becomes almost invisible

Researchers at Northwestern University in the US state of Illinois have developed a drone called Phantom Twist that spins around its own axis 25 times per second while in flight — so fast that the human eye perceives it only as a blur rather than a distinct aircraft silhouette.

Unlike conventional quadcopters, where only the spinning propeller blades are hard to see, this new drone works differently: it has just a single motor, and the entire body of the aircraft rotates, much like a flying frisbee. Because the whole structure is in motion, both the fuselage and every external component become blurred in flight, making the drone extremely difficult to spot visually.

According to project lead Michael Rubenstein, an associate professor of computer science and mechanical engineering at the university, artificial intelligence was used twice in developing the drone: first to assess how noticeable a given design would be, and then to help find the optimal arrangement of the drone's components in order to minimize its visibility in flight without sacrificing flight performance.

Rubenstein notes that at this stage, only the major components — batteries, motors and control boards — were factored into the visibility calculations. Smaller parts, such as cables and connecting rods, have not yet been included in the optimization, even though they too have a noticeable effect on how visible the drone is. The scientists believe that accounting for these smaller elements in future research could make drones even harder to spot.

Besides the obvious military applications, the developers also see peaceful uses for nearly invisible drones: such devices wouldn't startle or distract people and animals. Rubenstein expressed hope that the technology could be used for wildlife observation — in which case the drone's presence would not affect the animals' natural behaviour.

That said, Phantom Twist still has its drawbacks: despite its low visibility, the aircraft remains fairly noisy. The team is already working on this issue and plans to equip the drone with a quieter motor.

Around Prague, based on reporting by seznamzpravy.cz