Researchers for years have tried to make drones “disappear.”

They’ve used camouflage, transparent materials and light-bending optical systems. But a team at Northwestern University has a new approach: “motion blur.”

That’s the same quirk of human vision that makes fast-spinning fans and propellers seem to disappear.

The “Phantom Twist” drone spins up to 25 times per second, making it too fast for human eyes to see.

“For a typical quadrotor drone, the propellers are spinning, but the robot is stationary,” says Northwestern’s Michael Rubenstein. “So, you still see its body. For our drone, the whole thing is rotating, so there are no stationary parts.”

Researchers say this technology could be useful for monitoring nesting birds, surveying wetlands or inspecting aging infrastructure without disturbing natural behavior.

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