Peter Lynn ARCHIVE
Single skin kites that fly stably on a single line are by far the most challenging designs I have attempted in a lifetime of kite development. They are a completely new genre of single line kite in having no rigid members and no ram air inflated spaces to form their shape- which is otherwise difficult (I would have thought impossible at an earlier time) around the leading edge. The path to SSSLs came via the development of single skin traction kites which showed that leading edges can hold shape entirely by air pressure forces (though most reinforce with weedwhacker strip). However, SS traction kites have a pilot to fly them, so don’t have to be auto stable, and they do not experience the wide angle of attack and flying angle variation that single line kites are subject to.
Single line auto stability is a function of the complex interactions between structural deformations, lift, drag, weight and inertial forces in what’s called parametric resonance, understanding of which is not yet adequate to be generally predictive for developing single line kites that are auto stable in the required wide wind range. AI may come to our assistance in this someday.
With the usual process of trial and (much) error, I eventually developed some SSSL’s that could fly on a single line (Octopus, Serpent, ISkin, Sled) but leading-edge collapse and various associated instabilities limited their practicality. Angle of attack variations continued to limit their wind ranges, especially at the light end. 1Skins tended to ‘dive over’ randomly, a problem which was never fixed (but could be now I expect). Serpents fly well, but only in larger sizes because of a scale effect and Octopus SSSLs have a terminal problem with tentacle tangling that has prevented their general adoption.
For all these styles, special bridle settings were initially required for every wind speed in quite narrow ranges. Contriving automatic wind-speed dependent adjustments to reduce manual bridle adjustments was a slow process.
SSSL Rays emerged as the most promising option by 2018.
The first successful automatic range extending system developed for SSSLs in general is a bungy linkage that uses total kite pull as a proxy for angle of attack (there is less line tension at higher flying line angle and lower angles of attack) and lets the kite’s leading edge out in stronger wind. This extends their flying range by a lot but doesn’t work very well below about 15km/hr- a critical wind range for kite festival flying.
The second break-through was to not attach the centre leading edge bridles for 45mm back from the leading edge (5sq.m Ray) allowing this short section to fold back under when the kite is at lower attack angles (high flying angle). This prevents central leading-edge collapse in very strong winds. In conjunction with the bungy system, this pushed the 5sq.m SSSL Ray top end to more than 50km/hr and down to around 12km km/hr- but still not low enough to compete with standard Pilot kites in low wind conditions.
The latest (Dec 2025) improvement, developed for the 5sq.m SSSL Ray, is a 100mm wide full span width leading edge flap inside the leading edge bridles that lowers the leading edge by 100mm, substantially reducing the kite’s angle of attack to allow lighter wind flying while folding back under in stronger wind to shift the leading back up at higher line angles. This had been tried 10 years earlier on earlier SSSL’s (Octopus, Serpent) without success but worked this time by being made narrower and of very soft light fabric.
5 sq.m Rays now recover much better in lulls, with less inclination to fall off to one side when the wind drops and they will fly down to less than 10km/hr- truly a ‘kite for all seasons’- competitive with conventional pilots, if not yet superior (and at less than 1kg, 1/4 the weight of a conventional Pilot kite for the same lift). This improvement hasn’t cost high wind performance.
Nor are these auto bridle systems optimised as yet so there are likley more improvement to come.
Tuning the 5sq.m SSSL Ray:
Primary tuning is in the relationship between the leading-edge bridles and the main body bridles. When the leading-edge bridles line knot and the main bridles line knot are exactly beside each other, the 6th (furthest out) leading edge bridles and the tip bridles (on the main bridle set) should be the same length. At this setting the kite will fly in moderate winds but for stronger gusty winds the leading-edge set is let out a further 20mm to 30mm by letting off one or two turns from the loops around the carabiner on the front bridles leader line. The kite’s leading edge should be let out until there is no, or minimal leading-edge collapse (letting it out too much will of course effect light wind flying). For best light wind flying, the leading-edge set can be shortened (by taking more turns around the carabiner) but good performance across the entire range is available on just the one (strong wind) setting.
Generally, when flying at highest line angle, the leading edge may flutter a little. This is less destructive at the tips but can cause collapse if it initiates in the centre section- fixable by small adjustments of individual leading-edge bridles. When the kite is flown a lot in strong gusty winds (50kg and more pull), the main bridles can permanently stretch more than the leading-edge bridles (there’s more load on them). Over time this can be compensated by changing the carabiner loops as required but one 5 sq.m SSSL Ray that has been flown a lot in strong winds has not required any change now for more than 3 years.
Left/right bias
The first step is to check bridle symmetry left to right for all main and leading-edge bridles- +/5mm is adequate accuracy even for the leading edge. If the kite still leans, shorten one, two, or three of the internal bridles closest to the tip opposite the direction of lean. The easiest way to do this is to larks head or clove hitch a short piece of satay stick to the bridle to be shortened- keeping it close to the skin to prevent tangles.
Light wind flying.
To assist recovery when the Ray overflies in light unsteady winds, adding some weight at the base of the tail helps- there is a line loop to facilitate this.
These 5 sq.m Rays are high angle strong pulling kites. They can pull 50 kg. or more in strong winds- so take care, use line grippers and solid anchors.
Peter Lynn, January 2026.
