Any ideas on how to change the length of an endless rope drive during flight?

[PierreB]

I just realized (again?) that this topic has existed for years.

@Windy_Skies

I don’t know how this would work, but an idea inspired by this idea inspired by my idea

It’s partly that, or rather that some of your observations (see quotes below) encouraged me to see, in two times, what it was possible to do for takeoff and landing (if we want to use the rotation and the Magnus effect) by using the generator as a motor, knowing that it is not possible (to my and your knowledge) to vary the rope drive (loop or belt) length while it rotates the Magnus cylinder.

@Windy_Skies

I am not aware of any mechanism that allows a single continuous loop to be reeled in and out while the loop is being driven.

Me neither:

@PierreB

A rope drive can be unwound as seen in the Kitewinder video with the pulley-winch, and until it is completely unwound, not making power.

@Windy_Skies

@PierreB

For this, the rope between the two winches should be connected when they are completely unwound.

Yes, that might be the beginning of a mediocre idea, not that my similar one was that much better.

It remains to be seen: in the meantime, thank you for the compliment.

To get back to the basics, the rope drive (loop) does not allow you to take off using the Magnus effect.

But the @WindFisher double winch for one rope allows this maneuver as well as other maneuvers. This is an interesting innovation to credit this company. On the other hand, this system works specifically in yo-yo pumping mode which alternates the direction of rotation and the unwinding and/or winding of each of the winches in transfer of rope.
It would not work for long in continuous power mode with rope drive (loop, belt).

In the sketch I made and you quoted, after takeoff the rope is transferred from the double winch to the ground pulley of the rope drive system (loop, belt, rope without end…). I don’t know if this can work, but it looks possible.

This described device (with “two drums”) looks to be on the basis of the double-winch-one-rope from @WindFisher.

An another possibility, for vertically stacked balloons or other things (Kiwees?) is using the WindFisher double winch in the lower part in order to vary the rope length for takeoff and landing operations, then a chain of loops (rope drive systems) to connect the balloons two by two as also here.