Quad-Rotorcraft to Harness High-Altitude Wind Energy

  • Bryan W. Roberts
Part of the Green Energy and Technology book series (GREEN)


Wind at higher altitudes is generally stronger and more persistent than near-surface wind. At many locations the atmospheric flows have annual average power densities that by far exceed these of any other renewable energy sources. Capturing this energy potential has been the objective of a pioneering airborne wind energy concept based on a tethered rotorcraft which was invented in Australia in the 1980s. The chapter summarizes early research with a towed generating rotor, wind tunnel tests and a low-altitude atmospheric test vehicle. These tests have confirmed the feasibility of kite-like flight of a craft having twin or quadruple rotors with the rotors simultaneously generating electricity. Using high-altitude wind data statistics for Australia and the USA it is shown that near base-load electrical outputs can be achieved at capacity factors of 70 to 80%. The governing physical relations of the technology are derived from classical helicopter theory leading to the rotor thrusts and the rotors’ limits to power generation. The range of useful tip-speed ratios is presented for the complete range of rotor disk incidence angles. This mathematical model is used to describe the low-altitude operation of a small quad-rotorcraft. The model is suitable to predict the performance of a multi-megawatt machine. The final contribution of the chapter is a dynamic analysis of the system to devise a control strategy for the craft’s power output, pitch, roll and yaw, using purely blade collective pitch action.


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Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Altitude Energy Pty. LtdBrisbaneAustralia

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