The problem with flygen rigid wings of type Makani is the weight as they scale.
The problem with FlygenKite is the weight of the turbines aloft as it scales, that due to a relatively low speed (30 m/s (the double for Makani) with 10 m/s wind speed for a very favorable glide ratio (L/D ratio) of 5).
The problem with FlygenKite with a transmission ring (last sketch) is the complexity for implementation and high speed transmission problems. This has been confirmed to me by several experts including those writing on this forum.
A possibility is using light high density high rpm generators with a gearbox (peak power 1700 W, mass 0.395 kg of which 0.053 kg for the 6.7 : 1 gearbox). Other light high density generators: High speed generators ; Axial-Flux Motors and Generators Shrink Size, Weight (Magnax AXF275 motor (peak 300kW/rpm 8000, continuous 150 kW/rpm 6500, continuous 100 kW/rpm 4000, possibility for a gearbox) about 25 kg); https://emrax.com/ .
So according to my preliminary rough estimations, as the density of generators stops increasing from a certain speed (about 7000 rpm) because of problems such as centrifugal force, we will have a continuous kW/kg density of 4 for soft or rigid wings, but only 3 for FlygenKite because of the gearbox. It’s not a huge difference. It is also necessary to add a few kg because of larger blades for FlygenKite.
As an example a 4.75 m diameter turbine sweeping 17.65 m², would produce approximately 100 kW at 30 m/s (10 m/s wind speed) with a 80 m² flexible wing of glide ratio of approximately 5, weighing about 35 kg. A reasonable tip blade speed would be about 100 m/s (likely less than for faster rigid wings), leading to rpm 400. With a low enough (1 :10) ratio (two-stage) gearbox, rpm becomes 4000, so the rpm of Magnax AXF275 (generator of 25 kg, see above) delivering 100 kW at rpm 4000 in continuous operation. The turbine assembly (rotor + generator + gearbox) would weigh about 50 kg, + about 10 kg for the bar supporting the turbine. We understand that the kite remains lighter than the turbine assembly. It is therefore preferable to significantly oversize it (100-120 m²) to improve performance (in first the glide ratio with the turbine) for a minimal additional mass.
This would remain reasonable compared to a rigid wing of the same power, with the advantage of slower flight and lower cut-in wind speed. In contrast, a rigid wing will not suffer from the effect of moment between the wing and the turbine carrier system.
Take-off and landing operations are facilitated by the rigidity of the bar carrying the turbine. I observed that the kite took off easily manually.
The ground station would comprise two poles for the two ends of said bar, allowing the kite to expand. The turbine (generator as motor) would inflate the kite then allow to assure VTOL take-off, the tilted position of the whole facilitating the catch of the wind ending this phase.