Good question @PierreB.
Oddly though the same data seems to give us diametrically opposite conclusions.
Consider the following ring as a ground station PTO.
The red, green and blue lines hold it to anchors and can be extended and retracted, (let’s say in much the same way as rotating reel tethers can) But let’s just use these lines to allow the ring to be lifted to height and hold the ring against the torque of generation (blue cylinder)
Back in Feb 2014 I was drawing the logic of ground rails which would use tensile material to support rotary actions of kite systems … such as this…
So on the first drawing, Maybe the green ring is rigid, The yellow one doesn’t have to be. Green, wouldn’t need to be too heavy as long as the 2nd moment of inertia is good. The green and yellow ring could be configured like this tensile rail in the second drawing. Where the yellow PTO ring (1st drawing) is a tensile carriage ring array of inwardly connected rail carriages inside the supporting ring (green ring 1st drawing)
Say at the height of the yellow as show already… there is a wing deployed which just clears the ground. These wings arrayed around the ring will be potentially very light.
So … that’s an easily hoistable PTO, aligned to the axis in working operation, which lays on the ground for take off and landing, is large scalable and can support stacks of wide lightweight self expanding rotors… What’s not to like there?
So now that’s shared @PierreB, are you interested in it at all? … Or do you genuinely not like it?