Hollow-Axis Autogyro Kite Turbines
Consider bols, drogues,
Sept.22, 2019           Dave Santos
Priority Claim for "first hollow axis autogyro kite turbine"?

W&I claim on New Forum: "Daisy was the first hollow axis autogyro kite turbine. "

The theoretic advantage of a hollow axis is the absence of less efficient closely-axial mass. KiteLab/kPower looping foils are "hollow axis autogiro kite turbine" prior art, as well as  USWindlab's ST torque-tubes being arguably "hollow axis"prior art, just not much hollow volume.