With six cyclorotors, the BlackBird from CycloTech is designed to take off and land vertically, move sideways, brake mid-air and even parallel park.

The Z-drives include gear reduction and 360- degree thrust direction control in a compact unit. Elimination of conventional reduction gears and long propeller shafts frees up space for other uses.

they are quiet like straight teeth but they lack the axial thrust of spiral gears, and they can operate in both directions. They are also reportedly stronger than either spiral or bevel gears. Figure ...