Austrian company Cyclotech is planning to begin flight-testing an 80-kg (176-lb) demonstrator of its unique electric VTOL airframe, which uses Voith-Schneider propellers instead of rotors for exceptional agility and control in the air.

The prop design, which looks a bit like it belongs on the back of an 1850s paddle steamer, was patented nearly 100 years ago but hasn’t made it into a production aircraft yet. Each prop is a spinning cylinder whose walls are formed by a number of wing blades.

The secret to the agility of this “Cyclogyro” arrangement is analogous to the way helicopter blades work, continuously altering the angle of the blades as they spin to adjust and direct lift using a “swashplate.” In the Cyclogyro arrangement, a mechanical linkage – conrods connected to a central hub – is able to tilt and angle the wing blades as they spin around the cylinder, tilting them gradually into the wind as they reach a certain point in their rotation, and then gradually back to flat as they pass the peak point.