Three AWE preprints ready for feedback (Wind Energy Science Discussions)

[rschmehl]

We currently have three interesting preprints under peer-review in the journal Wind Energy Science:

• Duda et al: Flight guidance concept for the launching and landing phase of a flying wing used in an airborne wind energy system
• Elfert et al: Measurement of the turning behaviour of tethered membrane wings using automated flight manoeuvres
• Joshi et al: Performance modelling and scaling of fixed-wing ground-generation airborne wind energy systems

The journal handles an open interactive peer review to which anyone can contribute by posting meaningful feedback. Go to the “Discussion” tab of each preprint to submit a comment, which, after acceptance by the handling associate editor, will be published.

[PierreB]

@rschmehl

Elfert et al: Measurement of the turning behaviour of tethered membrane wings using automated flight manoeuvres

Hi @rschmehl, this is an interesting publication, potentially useful for many reasons: a tight turn (“sharp turning manoeuvres is illustrated in Fig. 1” page 2) could facilitate the use of larger wings compared to the tether length and the space use; depower (in pumping mode) could be achieved by “twist deformation” even during loop, even in the middle of the flight window…

This is what I tried and succeeded in testing manually with a 4 m² 4 line RAM power kite, today, in light wind. The control includes two handles with the respective bottom (brake) and top (power) lines.
The test:

1. I only pulled the right handle with a twisting motion, and the kite looped at least 3 times its wingspan, exerting a very strong pull.

2. Then I again pulled the right handle with the same twisting motion, but in the same time I pushed the left handle with the reverse rotation movement, and the kite looped at only 1 time its wingspan, being quite deformed and depowered.

I would suggest, but not in the peer-review process, to list the figures of more or less tight turns, executed by experienced kite pilots, so as to constitute a repertoire of practical work.

This catalog of figures measured by mentioning the wind speed, the dimensions and weight of the kite, the level of deformation and/or depowering, and with flexible kites of all kinds, could be connected to the theoretical work, and also the AWE tests that are performed in automation mode, leading to a possible appendix.

[rschmehl]

Thanks for the suggestion, @PierreB - I am checking with the lead author to see what material is still available as he performed the experiments.

But this will not be the last paper on the topic and it was not the first. Have you seen this one?:

Schelbergen et al Swinging motion of a kite with suspended control unit flying turning manoeuvres

We included some nice footage and even have a video as supplementary material.