FairIP index

It has slowly dawned on the soaring community that travel in any direction is possible merely by working surface-boundary-layer wind gradient. Strong wind gradients of all kinds offer this potential. RC soaring has even reached incredible speeds well over 400 mph. Similarly AWE theorists can now look beyond tethered foil pairs working gradients to tetherless single aircraft flying patterns to exploit the same effect. The variations are endless; for example, an aircraft looping in place in the surface gradient could transfer supercapacitor charge to the ground by "touch-and-go" contact by trailing electrodes, greatly mitigating conductive tether-drag limitations.

The recent debates and clear success in DDWFTTW (2.8 x windspeed downwind) has given us a fine lesson in the physics required. We now see a deep commonality of all sailing methods with land, water, and air interfaces seen as tappable differential gradients. It will take some really loopy thinking to work out all the basic points of "sailing in 3D," as Wayne put it, but for now, let's review the existing primitive state of understanding, and the topic will surely develop.

Dynamic soaring - Wikipedia, the free encyclopedia
A quote from the page:

In his 1975 book Streckensegelflug (published in English in 1978 as Cross-Country Soaring by the Soaring Society of America), Helmut Reichmann describes a flight made by Ingo Renner in a Glasflügel H-301 Libelle glider over Tocumwal in Australia on 24 October 1974. On that day there was no wind at the surface, but above an inversion at 300 metres there was a strong wind of about 70 km/h (40 knots). Renner took a tow up to about 350 m from where he dived steeply downwind until he entered the still air; he then pulled a sharp 180-degree turn (with very high g) and climbed steeply back up again. On passing though the inversion he re-encountered the 70 km/h wind, this time as a head-wind. The additional air-speed that this provided enabled him to recover his original height. By repeating this manoeuvre he successfully maintained his height for around 20 minutes without the existence of ascending air, although he was drifting rapidly downwind. In later flights in a Pik 20 sailplane, he refined the technique so that he was able to eliminate the downwind drift and even make headway into the wind.

Comment and development of this topic will be occurring here.
All, send notes, drawings, and photographs!