[10:00 Wed,22.July 2026 � by Thomas Richter] ��� |
To make objects virtually invisible, there have been various attempts so far—such as using cameras and projection surfaces, mirror and lens systems, adaptive displays, or so-called metamaterials. Researchers at Northwestern University have now introduced an interesting new method, specifically developed for drones, that takes advantage of a quirk in human perception.  Phantom Twist drone in motion
The Phantom Twist drone is an experimental single-propeller UAV with an unusual design: while the propeller rotates in one direction, virtually the entire remaining, highly delicate airframe rotates in the opposite direction at up to 25 revolutions per second. As a result, the individual components blur into a faint, semi-transparent veil to the human eye, which merges with the background. While this does not make the drone invisible, it blurs it optically, turning it into a kind of optical phantom. youtu.be/1mUgyV3A1O0 The Phantom Twist exploits the motion blur effect, which also makes the rotors of a drone or other fast-moving objects barely perceptible due to their rapid movement. The optical camouflage effect is based on how human vision perceives rapid changes: it does not perceive them individually, but rather combines them over a short period into an overall impression. A fast-moving object is thus no longer perceived as a clearly defined shape. Instead, the visual system averages the dark components with the background behind them. Therefore, the decisive factor is not only the rotation speed but also the spatial distribution of the components: they must overlap as little as possible to form a solid dark surface during rotation.  Phantom Twist drone - two different designs Operating PrincipleBut how did the researchers apply this effect to the entire drone? In a normal quadcopter, the central fuselage remains visible, and only the propellers rotate quickly. In the Phantom Twist, these otherwise stationary components—such as the motor, battery, control board, and counterweights—are moved rapidly because the motor is positioned outside the center of mass, and its torque causes the entire airframe, which is mounted in a support structure made of thin carbon fiber rods, to enter a rapid counter-rotation. This rotation gyroscopically stabilizes the drone; it is steered by modulating the motor thrust within each rotation.  Phantom Twist drone stationary Due to its design, however, integrating a camera into such a drone is difficult, as it would also rotate 25 times per second along with the airframe and would still need to produce usable images. Furthermore, while it is difficult to see, it remains very audible due to its fast-spinning rotor, which produces a typical high-pitched whirring sound. AI assists in designThe unusual shape was developed with the help of AI. The team simulated around 20,000 configurations and arranged the motor, batteries, control board, and counterweights in such a way that the center of gravity, aerodynamics, and flight stability were maintained. These models were then simulated in rotation and evaluated against about 100 real background images. The 500 most inconspicuous variants were selected and further optimized—based on this, several prototypes were built.  Phantom Twist drone Future useIn the long term, the new technology is intended to lead to drones that, for example, observe wildlife, survey the environment, or inspect infrastructure without being as visually conspicuous as before or unnecessarily disturbing their surroundings—though the rotor noise would still need to be reduced for this. Here is the research paper as  PDF.  �more infos at bei news.northwestern.edudeutsche Version dieser Seite: Phantom Twist - die Drohne, die sich fast unsichtbar macht |
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