Preprint: Fairly high pressure Flettner balloon ladders between ropes

[PierreB]

DOI: 10.13140/RG.2.2.30719.42406/1

Some ideas and tests for taking advantage of the rectilinear shape of Flettner and Sharp balloons to stack them between ropes have been gathered and clarified a little.

Some points:

Use as an AWES in pumping (yo-yo) mode with vertical trajectories

In the preprint, concerning Preprint: Towards a gigantic Magnus balloon with motorized belts :

At 10 m/s wind speed and above, a higher rotational speed, even resulting of same spin ratio of 1.21, would not be advantageous due to the power consumption which increases by the cube of the tangential velocity. It is the reason why a giant Flettner balloon with external motorized belts [9] in order to hold the balloon on its whole length was investigated: the large area compensated for the relatively low efficiency due to the limit of tangential speed imposed by the power consumption. But the maneuver of such a giant balloon is not easy due to the high inertia mass. So balloon ladders are preferred.

Luckily, new technologies such as drop-stitch or Shapewave ® [10] would allow cylindrical inflatable balloons to achieve much better rigidity. This makes it possible to envisage a much lower power consumption for the same tangential speed, comparable to what the curve in Fig.13 [5] shows. As a result higher lift coefficients Cl could be achieved.

Conclusion

Flettner and Sharp balloons have a rectilinear shape making them easy to stack in ladders from top to bottom and on the sides. In this way the maximization of space can be achieved, and over very large areas and at height where the altitude wind is more powerful and regular. The reasonable dimensions of the units facilitate their manufacturing and implementation.

[PierreB]

Wind Fisher technology is interesting because it allows a Magnus cylinder to rotate while varying the length of the ropes to respond to the reel-out and reel-in phases of the pumping mode, using winches located in the ground station.

This makes it possible to avoid having to bear the weight of the rotation motors in flight, and to do without the electrification of the cables to power said motors.

This is already very interesting for a single balloon.

This would become even more interesting for a balloon ladder.

For this the @WindFisher four winch and two rope system would be used for the first balloon (starting from the bottom).

Then two belts would connect the first cylinder to the second cylinder, then two more belts for the second and third cylinders, and so on. A belt connects two cylinders.

Using in pumping mode with more efficient crosswind vertical trajectories compared to basic control. Perhaps horizontal trajectories could also be used, but this would lead to a higher spin ratio of the cylinders, so a higher tangential speed, because the linear speed becomes higher, hence more consumption power (which increases by the cube of the tangential speed).

Of course we would have to see if all this could really hold up to use. A sketch: