Abstract: A drone including a body and a rotor unit, the body has a substantially cylindrical outer lateral surface, and at least one energy storage element of the drone is arranged in the body. The rotor unit is connected to a head side of the body, and the rotor unit comprises a first rotor with first blades and a second rotor with second blades, wherein the first rotor and the second rotor are arranged coaxially to each other, the first rotor is designed to rotate clockwise about a rotational axis, and the second rotor is designed to rotate counterclockwise about the rotational axis. The first blades and the second blades are mounted such that they can be freely folded so that they rest against the body in a rotation-free state.

Abstract: The invention relates to a waterjet propulsion system (1) for a watercraft, comprising an intake region (2), an impeller region (3) which adjoins the intake region and in which a one-stage impeller (4) is mounted, and an outlet nozzle (5) which adjoins the impeller region, the waterjet propulsion system having a drive motor (6) which is at least indirectly connected to an impeller driveshaft (7) of the impeller (4). According to the invention, the impeller has only one single blade (8).

Abstract: The invention relates to a waterjet propulsion system (1) for a watercraft, comprising an intake region (2), an impeller region (3) which adjoins the intake region and in which a one-stage impeller (4) is mounted, and an outlet nozzle (5) which adjoins the impeller region, the waterjet propulsion system having a drive motor (6) which is at least indirectly connected to an impeller driveshaft (7) of the impeller (4). According to the invention, the impeller has only one single blade (8).