"The actuators on the airship work - like biological muscles - in an agonist-antagonist configuration. While the actuators on one side of the airship are activated, the corresponding actuator on the other side contracts. Thus the body and tail fin are excited in an undulating movement which propels the airship like a fish through the air. The EAPs can be actuated with varying frequency, activation voltage and a phase shift between the body and the tail fin movement. In fluid-dynamical similarity to the rainbow trout, the appropriate motion pattern (deflections, frequency and phase shift) were defined and verified by wind tunnel tests. The expected travelling velocity was calculated. The "skeleton" and passive parts of the airship consist of an ultra-light carbon-sandwich structure and a model-airship hull material developed by aeroix GmbH in Berlin. The electrical supply and control system was developed at Empa and everything was optimized for minimum of weight. The flight of this fish-like airship can be controlled with a joy stick connected to a ground-based portable computer. The flight control data are processed by a LabView program and transmitted by WLAN to the receiver system in the gondola on the airship."