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Строка 133:
It was shown by Ganuaa ''et al'' that with 100% efficiencies (i.e. no losses in the drivetrain, on the wind turbine or on the propeller) and with no drag other than associated with energy harvesting (e. g. no aerodynamic drag besides the drag of the wind turbine) there's no upper limit to the speed for such a vehicle neither when travelling upwind nor when travelling downwind (regardless of how small the speed of the wind is). In practice, however, losses in the system and aerodynamic drag of the vehicle's hull limit the maximum speed that can be obtained for a given wind speed.<ref name = Gaunaa/>
 
The same principles are applicable as well to a watercraft using a water turbine to drive an airscrew, as is shown by Mark Drela—a [[MIT]] professor of [[aeronautics]] and [[astronautics]]—was the first to demonstrate mathematically the feasibility of the "Dead-Downwind Faster Than The Wind (DDWFTTW)" both for watercraft (using a water turbine to drive the airscrew propeller) and for wheeled vehicles.<ref name = Drela>{{Cite web|last=Drela|first=Mark|title=Dead-Downwind Faster Than The Wind (DFTTW) Analysis|url=http://www.boatdesign.net/forums/attachments/propulsion/28167d1231128492-ddwfttw-directly-downwind-faster-than-wind-ddw2.pdf|access-date=June 15, 2010}}</ref>
 
=== References ===