Design and testing of a remotely controlled surfkite for the Laddermill

This paper presents the design and testing of a remotely controlled surfkite for the Laddermill. The Laddermill is a novel concept to generate electricity from high altitude winds. It generates electricity by pulling a rope from a generator, with lift generated by kites. Part of the rope that is connected to the kites is wound around the generator. The kites pull the rope from the generator, thus driving it. Subsequently the kites fly down in a configuration that generates significantly less lift than during the ascent. This way the tether is retrieved and the process is repeated. The Laddermill concept allows very large single unit powers. For an early demonstration of the Laddermill principle, a commercially availably Peter Lynn surfkite is used. This surfkite is radio controlled, by means of drag creating actuators on the wing tips. This paper presents the actuator design and results of testing of the surfkite. Preliminary results of generation of Laddermill energy are also presented.