Fort Felker (please see the attachment below or the link above): “Our largest kite to date, it has a wingspan of 26 m, and has eight onboard rotors that are each 2.3 m in diameter. For comparison, our previous prototype, Wing 7, was a 20 kW system with a 8m wingspan and with four rotors 0.7 m in diameter.”
The turbines aloft should add 1/2 drag of the wing alone in order to reach an optimal efficiency, the speed becoming 2/3. I checked this with my FlygenKite:
(please see also my comments as corrections).
But the drag of “eight onboard rotors that are each 2.3 m in diameter” (33 m²) seems to be largely above 1/2 the wing alone drag. Have you some explains please? Is it the large drag of the support of the turbines?
ch01_awec94_Felker.pdf (2.2 MB)