Comments by "Tony L" (@tlangdon12) on "Are Vertical Axis Wind Turbines Better?" video.

The rotor configuration is important to the self-starting characteristics of the rotor. The graceful curved blades on some Darrius-type VAWTs are not there to look nice, they actually improve the ability of the rotor to self-start because there is always some part of the rotor that is at the optimal angle of lift to start the rotor turning, and as that part of the rotor turns away from that angle, another part of the rotor is turning into that optimum angle. Self-starting behaviour is a particular difficulty with VAWTs, but it can be overcome with careful design.
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@EngineeringwithRosie I think the question you posed as to whether VAWTs are not efficient enough yet for commercial use is due to a lack of development or an inherent inefficiency is a great question. It's not that they produce no energy; while it is certainly true that there is published data that shows certain VAWT installations did not performed well, these tend to be in poor wind sites where a HAWT would do no better. There is other data from large VAWTs in good wind sites that have produced a lot of energy quite reliably.
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I'm not sure if you are aware of Vertogen, but they are working on an self-governing variable pitch VAWT mechanism that might improve the efficiency of VAWTs significantly. It might be fair to say that "automatic variable pitch" is the holy grail of VAWT technology as it promises improved efficiency, improved self-starting and another layer of safety against overspeed. Only time will tell if the benefits outweigh the downsides produced by the complexity.
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@EngineeringwithRosie I think Drema Boy is suggesting that the generating coils/magnets for a VAWT could be more efficient if they are positioned at the periphery of the rotor rather than in a relatively small PMG driven by a shaft. His point being that the linear velocity at the periphery is greater than at the centre. I don't know enough about generator design to know whether he is right. :-(
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@EngineeringwithRosie Are you familiar with Qblade? I've done some work with the VAWT modelling in Qblade as part of my research into VAWTs.
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@EngineeringwithRosie Lower to the ground will definitely help, but the rotor diameter tends to be lower, so the force at the tips is lower. VAWT tip speeds never reach the supersonic!
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@ДэнКошман HAWTs and VAWTs place a great deal of cyclical stress on the components of the machines, so both are subject to failure due to fatigue. I don't think you can say that only people who don't know much about aerodynamics are engaged in VAWT research; I tend to agree than many people tend to ignore the fundamental aerodynamic issue with VAWTs - that the blades experience a variable local airflow as they rotate, but there are aerodynamicists working on variable pitch VAWTs specifically to reduce the effect of this variable airflow. Whether the complexity of the variable pitch mechanism provides a useful degree of additional energy extraction is still to be seen, but these are aerodynamic experts who are working with VAWTs.
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