The double skin concept appeared in 2001 with kitesurfing so more than 20 years ago , but this time with ram air and ribs for wingfoiling. It failed with kitesurfing because the increase in efficiency did not compensate the weight increase due to the double surface - a single skin was already extremely efficient.
Today, this ram-air solution is said to improve speed, jumps and upwind angle… same verbatim as in 2001. Maybe with 2023 materials (Aluula or equivalent + light fabrics) + the Ozone experience, the promises will be kept … Let’s wait for the first genuine tests…
The Gong PULSE DP UPE Aramid: their race wing
Double surface on the first half of the chord only (lighter), the profile and overall structure seem locked
Aramid = Kevlar (trade name)
Date Oct 12th 2023
Combinations of inflated structure and cell-kite had not much (if any) performance gain from what I can remember (kite named Orca maybe?).
However, Peter Lynn Arc style kites (twin skin, cell structure kites without bridle) had some nice features, such as auto-zenith, small pack size, light weight, pumpless.
The reason they don’t exist anymore was likely not related to weight, but rather the limitations in depower range, and perhaps water launch handling. Had a bunch of these kites (Arc, F-arc, Guerilla, Phantom etc.) and still use them occasionally. Even sewed some of my own back in 2000
My first kites I tried on water had 50 m lines (C-quad, Mosquito). During the years people used shorter and shorter lines. Wings kind of took this to the extreme and just put handles directly attached to the wing. I like it. If there are such nice winds available, why bother with lines?
Perhaps a smoother transition on the underside of the profile (as these Fusions) could add a bit more grunt to the wings, but also a step backwards in terms of simplicity.
If efficiency is the goal, then perhaps one should consider making wings designed a bit more like the PL C-quads. These had some nice power and speed, single skin, a thin stiff leading edge, few seams.