The rotating reel system is a TRPT device without rigid parts, so a fully TRPT.
https://www.researchgate.net/publication/324135034_Airborne_Wind_Energy_Conversion_Using_a_Rotating_Reel_System
There is an analysis of the transferable torque on the figure 22.18. The “shaft” (in reality the peripheral ropes) varies a little in diameter, but in the other direction as the ground rotor diameter in the example is 50 m while the inner flying rotor diameter is only 40 m. I mention it in order to be quite on the topic.
@tallakt’s analysis has shown the limits as the system scales (huge?). Indeed I mentioned 1 MW, thinking this value is still too low imho in regard to the tether length for economical reasons (land use 4 km²) Medium scales for torque transfer systems onshore and offshore. From the analysis I mentioned a weight of 5623 kg for the rigid rings for a 1 MW system (by going from 1 kW and a weight of the rings of 1 kg), so 5 times M600 weight.The complete discussion from Tallak’s analysis shows also some nuances.