howto DIY 250 Watt VAWT glasfiber/xps two-blade H-Darrieus
Channel: robo durden
Date: 06/08/2023

https://www.RoboDurden.de :-(
Here the two papers i found, do not know how long they stay online:
https://www.researchgate.net/publication/347984992_Experimental_observations_on_efficiency_difference_between_helical_and_straight_bladed_vertical_axis_wind_turbines
https://www.researchgate.net/publication/344928008_Vertical_Axis_Wind_Turbines_Optimal_Positioning_of_the_Blades_Defined_by_Asymmetrical_Airfoils