Build a Darrieus Rotor yourself: Your project box includes 79 original patents as a fun way to reach your goal! Darrieus Rotor build it yourself: A collection of 79 patents on 632 pages. All patents, companies and individuals have registered on this topic. Nominal value: EUR 276.- (official price for patent research at EUR 3,50 / patent). Simple, intuitive navigation for selecting the patents.