Kite soars high with lightweight wings

Researchers at the Materials Science and Technology Institute (EMPA) are also exploiting wind energy by pulling a cable from a drum to turn a generator. 'Tensairity' elements made of air filled membrane assemblies, rods and cables have already made a name for themselves in the construction world as extremely light, yet strong load-bearing structures. EMPA researchers are currently pushing back the envelope in this field and are also demonstrating their first flying models. A team from EMPA, headed by Rolf Luchsinger, wanted to make use of a demonstrator device to find out where, from an aeronautical point of view, the limits of the technology lie, and whether a Tensairity kite would offer any particular advantages. The biggest Tensairity kite developed so far has a span of 8m and a surface area of 11m² and has undergone numerous load tests in the laboratory. With a weight of 2.5kg, it is designed to generate a tensile force of 1000N, and could, in theory, climb to an altitude of 4000m. After the extended design phase and subsequent construction of the demonstrator kite, the researchers were keen to try out their baby. The first tests were conducted at an obsolete military airfield in the Bernese Oberland, where the kite was towed behind a car at a height of 50m along a 1km long course. Luchsinger was happy with the outcome of this initial trial and is already planning his next project – a kite with a span of up to 30m with internal structures filled with helium, capable of staying afloat even with no wind.