Hi Pierre: There was very little wind that day, which is normal for any time you have a film crew or any interested visitors flying in from another country expecting an “instant demo”, whether or not there is even any wind on a given day. That’s just the nature of wind energy - wind is intermittent, not always blowing hard, and amazingly, your average person is often surprised to realize that actual wind is required to do wind energy. At least there was SOME wind. You might notice that right about 11:00 in the video, just after startup, you see the driveshaft visibly lift and straighten as the rotors acquire lift and thrust force from spinning in the slight, yet barely sufficient, wind on that day.
If you check out this video,
there was more wind (still not a strong wind, but a decent wind) and we used a kite rather than balloons. The balloons work best in low winds when a kite might just fall out of the sky, but as soon as you have a decent wind at all, the kite pulls everything taut, straighter than the balloons could…
