The key drawbacks include the relatively low rotational speed with all the consequential increasing torque and hence more expensive associated with the drive train, that inherently reduce power coefficient, that the three hundred sixty degree rotation of the aerofoil in the wind flow throughout every pattern thus ones extremely dynamic loading regarding the blade, the pulsating torque generated simply by a couple rotor designs regarding the drive train, as well as the difficulty to modelling ones wind movement accurately and hence the challenges concerning analysing and designing the rotor just before fabricating one prototype.