Dave Santos just posted on the topic:
“SS” means “single-skin”, of course, but “TS” is more obscure; its Peter Lynn’s “Twin-Skin” (parafoil) usage to avoid confusing DS “double-skin” initials with DS flight. We have long noted that SS wings are theoretically superior by power-to-mass and power-to-cost, also found that to be true in empirical practice, and we have followed the ongoing revolution in SS wing design in recent years. The NASA Power Wing (NPW) remains the standard workhorse, Dave Culp’s OL Shipkite is a classic radical simplification, and new SS paragliders and powerkites are the avant garde. Dave Culp long ago predicted that SS kites would eventually dominate large power kites, which I agree is likely. This message adds Luff Rate to comparative SS-TS theory.
Besides lower-mass-by-area and higher-power-to-mass of an SS over a TS, the most distinguishing characteristic between the two kites is the Luff Rate. An SS kite will luff faster and recover faster. SS AoA tolerances are a bit lower, not as much as one might fear. On the TS side, valved ram-air intakes add a bit of mass and further reduce luff. At a given velocity, Luff Rate is determined by the thinness (depth-of-section) of the wing, the thinner wing having an inherently faster luff. Kite Control does not react in time as easily to a fast SS luff. However, for equivalent-mass SS and TS wings, the larger SS kite’s luff rate is moderated by its larger size, and flown in weaker wind, and this slower response is operationally significant. A smaller TS in faster wind can be twitchier than an equivalent power SS in slower wind. An SS kite is more prone to flogging (harmonic luffing) damage, but excess flogging is a duly avoidable state.
This is a start at understanding Luff Rate as an SS v TS design and operational factor. Its an open task to formalize luff mechanics in terms of Strouhal numbers, Re, quantum-of-action, etc.
Adding here some damping-factors on Luff Rate and Luff Amplitude-
SS Luff is damped by fore-and-aft multi-bridling and camber of the wing. Multi-bridling inhibits bulk oscillation and high camber restricts luff to the LE area.
TS Luff is damped by parafoil-cell (airbeam) buckling, which can be interpreted as a slow-phonon effect, under sonic relativity.
Luff Rate (Frequency) and Amplitude reflect a close relation to harmonic flapping (and flogging) dynamics.
The single-skin lower mass overhead favors a lower cut-in wind speed. So a significant advantage of SS is a drastic decreasing of landing and recovery operations.