KiteBotopen-source super-kites
Good old string & rag beats stinkin' oil .
The singleline kite is a carbon-based composite stone-age UAV. Its analog-computing autopilot technology is truly old-school cybernetics, still state-of-the-art &, biofiber based, fully compostable. Single-line kite logic is situated passive-powered computation, default control for problematic electronics.
Kite problems yield to animism & heuristic taboo, not to mentiopn dynamical nonlinear analysis. Kites operate chaoticly, with sudden transitions between modes. Flight is metastable, the kite-eating-tree is a stable ambient state.
musical aeroelasticity science where flow, inertia, & elasticity combine across fractal scales as winged harmonics. Ruinous chaos is dampened away by parallel capture to abitrary reliability.
Passive stability must underlie unreliable electro-mechanical kite automation. Forged from tragedy airplanes are created with inherent passive stability. The Asian cone hat story of kite first-flight has a mechanism, "snow-plow" stability, where angled surfaces (dihedral) restore a perturblenced kite's optimal relation to wind. Rag-flapping wing-tips differentially orient kites.
Such stability features, by adding a bit of drag also auto-limit overflight. Bridles string-compute anti-roll & pitch (AoA) input. Tails dampen wind-turbulence harmonics that would otherwise entrain the kite into death-dives. If the protro-kite was a human-piloted nomad tent or canoe-sail, then multi-line kites precede stable single-line kites, which are subtly more complex.
Chaos, complexity, & dynamical aeroelastic systems theories point kiting toward reliability. Even the simple spectral analysis of wind frequencies informs better pilotage. A big step will be to include vortical handedness information in wind data. A reverse butterfly-effect controller is called for, where tiny inputs amplify into sound flight performance. Actuation force developed at the kite eliminates long wires & excess battery mass.
Anchorage
Ground is cheap structure for kite-farm spreading & capture functions. Anchor & mooring systems must align with veering winds while holding monstrous loads. A kite field will be a grid of flush soil anchors (Anchor-Field) available to the flying net like the cleats & toe-rails of a sailing yacht. Soil kites can permanently anchor in loose soils & muck. Bag-like sand-anchors have the advantage of dragging in a soft-failure mode, over the potential disaster of bounding anchors.
PolyKiting- Flying Wind Farms
PolyKiting integrates diverse kite methods/styles as networked systems, massively parallel element arrays that subsume local chaotic failure & scaling limits. Large kitefields will be cellular & fractal nets of lifter cells, power cells, & work-cells across anchor grids,
Auto-Launch/Fly/Land
Auto Launch & Relaunch is key to many kite apps. Some kites naturally relaunch if they come down face first (West Indies Moon Kite) or laying on a side (Morse Sled).
Self-relaunch can involve a cascade of pilot lifter elements, optionally helium based, or maybe a UL kite with a boat like belly, landing legs, or runners (ckicken-sticks) that allow kite wing to catch breeze as ground-effect. Vortical filaments drag across the ground & pick up waiting kites, the same way baby spiders kite away on a thread.
Frames, masts, & lines can launch, catch, & relaunch large kites. Launch & retrieval sequences break the giant-kite problem down into managable little pieces.
Landing on cradles, landing legs to relaunch.
Rapid reel-in of a pilot can generate the reaction force required to launch a large kite element.
Helium pilot kite at altitude relaunches grounded kites. A modern sled inflates to relaunch, un-fanfolding into upright relaunch. West Indies Kites relaunch (& takes high wind). As Granadan kitemaster George Peters told me, "They hop right back up." A "chicken-stick" holding up the LE of a delta or similar kite enables self-relaunch. A chicken-hoop, to coin a term, can roll a kite off its back for relaunch.
Variable bridles, active bridle, flip-flop, elastomer TE bridle,
Hot-Swapable Kite Elements
Hot-Swapping parts is key to broad kite applications. Hot-Swapping also helps with polymorphic initial modularity, Malraux's "youthful pastiche" phase prior to mature integration, & as prototype elements are unreliable & highly variable.
The New Working Kites...
... will look like a skirted flat-worm or stingray, the mid-skirt performing hi AoA traction-flap function balanced at the line axis. A flattened tail develops some lift which, dumped as the kite overshoots zenith, brings the nose up to recover.
Variable Configuration- to match applications, locations, conditions; calm to storm functionality
Multi-Functions- energy, communication, environmental remediation, transportation, recreation.
Messingers aloft elements along a kite line. These can be functional, like a different kite-string that connects as the old one disconnects & retracts. Additional sail area or tails can be swapped. Kite-elements can fly into place & dock, as UAVs, in effect commuting to & from work.
Kites are ultra-low wingloaded compared to regular aircraft. Kite-power doesn''t scale monolithicly. Static wingloading remains constant as structure grows too heavy. Even soft kites can't get much bigger than historic airships without massive rip-stopping & load-path fan-ins. Altitude scales with severe trade-offs in line weight/drag as ultimately wind-energy tapers off in the middle stratosphere).
Local advantages can pay- terrain winds- gap winds & mountain waves, atmospheric jets of many kinds, sought actively, can greatly enhance output. Chasing the invisible convection tails under common cumulus greatly boosts available power.
They cope by ultra-lightness, sweeping, & seeking better wind (jets, upper-altitudes).
Sparred (sticky) kites are limited to dimensions units under 100m. Tether drag & weight limits operational ceilings.
Fundamental line reliability in high wind (with worn line) trades against performance in low wind.
A soft ladder-mill has advantages over a hard ladder- less weight, safer, cheaper, & so on. A proper ladder mill should "reach" across the wind, not "run" downwind, to get sweep advantage.
Even kites intended as non-sweeping sweep anyway in natural wind. Trains of identical elements show a stable short sweep oscillation (higher mode harmonic).
A design language of sweep amplification & dampening holds promise where normally unstable devices swing like pendulums under a stable lifter kites. A turbine generator could develop high inertial force swinging under a slower kite.
Even "stable" kites sweep in real-world helical wind fields. In a shed-vortice wind field a simple kite can provide a pulsing power signal.
Compliance with chaotic gust inputs is a key to stability, stay loose like floppy delta-kite wings developed in turbulent Texas air.
Loosely tethered kite arrays stabilize against local instabilities. Such a cellular net has the stability advanage of a single giant kite without operational & structural impracticality.
Structural compliance obviates complex power-draining actuation.
The physics of large synchronous arrays of sweeping kite elements works nicely, like a flock of birds. Nature finds no better way to fly biomass cross-country than as a group of small units (packet switched nets), lone giants don't do.
Heresy
Jerry is a gentle kite flier that, by tinkering, found his own truths at odds with conventional kite truisms; he down-bridles deltas in rising wind (while adding tail). He had found a nonlinear kink in the bridal setting stability curve. Like the instructions on kid's kites, i always added tail & up-bridaling to reduce high AoA pull. What's up with that?
Partly a delta's tendency to self furl in gusts is enhanced. Many kites have an island of instability in bridle position between low to high AoA lift modes. Kites use swept surfaces to ease nonlinear lift transition, particularly from high AoA horizontal launch to Low AoA flying angle. Different parts of the kite transition at different times, buffering local instabilities.
Kites with "spill-wind" wings, like Japanese designs, get magnus lift & gryroscopic stability from Taylor rolls formed above the wing, structure made of flow iself.
Many great Asian kites, like the Thai chula, have a large delta form nose before a high aspect wing, that folllows this logic. The nose also helps keep the wings level, its turbulation field shifts an energized boundary layer over the drooping wing, enhancing its lift.
Kids' Joke: What monster kite-flies thunder-storms? Benjamin Frankenstein
We share partial patterns of emergent divinity, profane versions of more evolved forms & somehow the kite is a portal to deep mystery.
Envy of the old Space-Age, the boomerang is over 40 thousand years old. The SE Asian kite may be similarly ancient. As with Magdelanan culture, SE Asia was a drowned Atlantis of the post ice-age sea level rise, where kite origins perhaps disappear underwater. The Chinese say they discovered the kite. Wondrous traditions support that belief. Even so, Pacific sea folk made the kite a central tool & motif in the most fluidic way-of-being of any people until surfer punks.
Kiting is old paleolithic sorcery. New spells such as the Kite Torque Equation work stability & equilibrium magic. Control actuation & computing helical wind-field spaces is a NeoVoodoo. The Kiter's death-dive is the towed glider's lock-out, aviation's blood sacrifice pre-paid.
A hot kite "ignites" by crossing the power zone in a blow, accellerating many times faster & exponentially more powerful, as wind grows.
The Kite Whisperer
The Kite Masters' quest faces a puzzle-wall. Kites are essential child's play, modest success certain, yet transcendant first-flight commonly ends in minor grief; a kite-eating tree, runaway, or crash; even still air is sad. The technologist's despair is that serious adult kites stubbornly retain childhood's wildness into monstrous engineering scales; nuke power thrashing on a giant string.
torque equation extended by wind-field helicity. an intractable multi-body problem.
Reliable kites don't exist, for obvious & mysterious reasons. The 2007 kite studies still found missing science holes. Kite physics is poorly formalized.
Like magic breadcrumbs, the research trail wandered into exotic Asian & Polynesian mysteries of adept sky cults that ages ago beat NASA & the rest of the West to aerospace level design. How weird to find in our Space-Age that elite kite design is still a shamanic black art, a realm of sorcery, (straight-up; Dog, do not read further, unless you're down).
Real kite-secrets reverse common sense; truth appears backwards or upside-down. Andy Wardley's long sought super-kite only worked face-flipped, as if Linda Blair's head really turned. Flying backwards Joe Hazickski discovered an essential secret of flying forward (meshilated LE). Even deciding which part of the kite/flier system is left or right is disputed.
Until recently experts still asserted "kites are certainly not 'developed' by thoughtful engineers." [van der Horst & Velhuizen, '94], not actually true. "Thoughtful engineers" have worked on kites, usually doing as well or somewhat worse than the historic freaks, mystics, artists, con-men, tinkerers, & countless natives who made kiting what it is. Several engineers worked brilliantly, in our time Peter Lynn stands out, but the little kite's problems are deep, whole lifetimes leave tiny marks.
Dave worried bad-air might ruin my track to kite mastery. To play safe i flew months of quazi-laminar Pacific wind, but it's comparatively dull polishing one's sweep or watching plastic "pasted-to-the-sky". Did not young Maestro Jordan fly into legend out of tangled air in Florida's piney woods?
So i found an odd breeze in the dark understory hillsides of the towering NorthWest woods, shallow falling rivers of cool air that leave tree tops untouched. I happily took up weird flying under the tree canopy, inspired by Jordan, who boldly buggies under piers in his path.
I passed months of endurance kiting working on reliability. A barrier Jim Patton hit flying his thousand foot trains was bathroom breaks. Seriously, how do you pay continuous attention to a monster kite when nature calls? It seems a minimum 24 hour crew of three on eight hour watches is required for maximun duty cycle. As Charlie Jackson kite-buggies in & out of the registration tent at NABX, his kite flying out the entrance, i found it possible to use the beach public restroom still flying, unreeling line as i went & entered buildings like the World Kite Museum, unreeling deep into them, the kite parked outside above.
Mastery of kite operations in obstacle-fields like forests & cities. Birds are the existence proof, operating almost anywhere.
Scouting & tricky flying kept the kite clear under trees, wires, & bridges, between buildings & towers, so yes, kites can fly wherever birds can. During these experiments i never lost a kite. The science-kite's water relanch capability (keel-float) saved it when it once landed on a roof puddle. I didn't see hat relaunch, but the kite was dripping wet. Several tree foulings proved Bondestam's idea that rythmic tugging generally releases a treeed kite.
Technical Kiting
Technical Kite Systems rig like sailboats & fishing tackle, diverse multiple elements strung on a multiple lines, literal net-works.
Kites can replace much of conventional aviation & open vast new applications. Already some kiters live off KAP, (kite assisted photography), a little kite displacing a helicopter while expanding arial photography.
After calm, a small toy-balloon scale helium lifter kite lifts a windcatcher surface to re-launch a big power kite, provided you have automated control OR a cheap sled kite lifting a high L/D sweeping foil to do the pump function, without special control, at high efficiency. No human 7/24.
An umbrella is needed to bring together all the DIY appropriate-tech prototype scale schemes in a collaborative push.
kite energy, kitebot, autokite, superkite, aerospace kite
Santa flys a Sled
Humble "rag-flappers" are cheap simple single skin construction held open by the wind. NASA Parawing clones are popular cheap alternative to fancy traction-kites. KiteShip's OutLeader ship kite is the ultimate simplfication of a power-kite, three line single skin, Superman's cape, XXXL.
Modern sleds were anticpated by Hungarian & Tunisian kid kites. The nomad tent is an original traction-kite. Folks repeatedly saw kite phenomena, invented the device & as often forgot the principles. The simplest kite, a Playwing, is a cloth rectangle with corner-strings held by four flyers. Flying-carpets are ordinary kite-magic.
Many kiters despise the sled for its virtues- too stable, cheap, & easy. Kitefishing & lofting Line Junk are niches where the sled is accepted.
Allison & Scott where both of Dayton Ohio, the Wrights' hometown, yet never met; little Dayton a psychogeographic singularity, a Florence of Flight. The misleading Scott Sled name endures, evoking Capt. Scott's sleds, not the FF sled the inventor's marketing notion (plus penny-pinching-Scot archetype).
Morph cheap sled to KiteShip's Outleader, like adding mustang DNA to a racehorse genome. The kite designer may choose from naturally-selected sled variants, various soft keels (just stiff enough to uncurl from luff), diverse vents, catenaried or hooded LEs, swallow tailed TEs.
Single line kiting & multi-line kites develop somewhat independently, then features suddenly jump from one class to the other by extingencies like converting a multi to single or vica-versa. The modern work-kite will be single line with multiline control from the bridle-point.
The simple sled is a reliable kite; a Hawaian Ham relates-
For wind measurements I have flown simple tethered sleds in the trade winds for weeks at a time. Our record was nine days that a sled stayed up, staked to the ground, day and night, through land breeze/sea breeze transitions, with no intervention. It was finally collapsed and knocked down by a nasty gusty roller of air. It took seconds to shake it open and relaunch it.
That sled might have relaunched by a leading-edge un-fanfold process inherent in the type.
Kiting Wonderlands
NABX
The great kite sorcerers, the most highly technical fliers & designers in the world, convene in springtime on a surreal plane, a baked playa of the Mojave Desert, to practice the infant extreme-sport of kite-buggying. This is no child's kitefest; killers writhe monstously overhead.
NABX is an enchanted forest for LIDAR study, a kite-swarm, a terrabit-scale data set that, revealed in fluid-dynamic animation, would blow us away. Here kitepunks of scant sailing theory or abstract physics nevertheless developed very fluid, very advanced kite-flying. While i out-pointed & left the kite-punks to leeward, my sail-trimmer roots at work, embarrasingly i was almost stranded to windward, an Ancient Mariner dreamstate. Downwind the punks did things i was ignorant of, chaos mastered, sweeping wild compound lissajou curves in the turbulent wind-field;
strange caustic patterns of natural & artificial flows.
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Aeroelasticity science encompasses entire kite systems, from anchor to tail, where the kitelines are key dynamic elements.
Turbulence, niose, is substanially fractal, & so is the kite airframe that adapts to turbulence.
A kite acts like a artificial soliton in the natural wind, or a packet of solitons, an oscillon/wavelet, commonly a Mexican Hat or Hermitian oscillation imposed on flow.
Kites transition across various dynamic modes according to wind, design, & trim.
A dancing kite may dance led by turbulence, or on its own harmonic coreograph, or the interplay of both regimes.
Stochastic Resonance (SR), where a little noise helps a system find equilibrium, helps kites fly better. The hummer on a West Indies Moon Kite vibrates the airframe so mightily in a gale that normal limitations on a "flat" airfoil are suspended, the kite approximates a locally compliant, yet overall stiffened, rounded wing. A related effect is oscilloscopic stability where vibrating mass aquires a resistence to pertubation.
SR works where "stick-slip" dynamics cause problems, in kites violently shed vortices are stick-slip-like destabilizers, & turbulators add noise to keep the slip from kicking the kite into a death-dive.
Large phased arrays of kites cancel out chaotic subfailures. The proper spacing of semi-captive kites achieves determinism while maximizing efficiency.
An charged solar-sail develops electrostatic " bernouli lift".
ultra-low dc to usable dc upconverter TI makes a nice little surface mount DIP for milliwatt apps, but what we could really use for a current 60th scale prototype would be a flexible device in the 10 watt range able to take a volt or so to 5V or 12V at high efficiency, easing starting resistance & provide scale data for feasibility indications and consist of a small foam turbine pulled aloft by a helium pilot kite transmitting power by a loop of line turning a small gearmotor on the ground as the generator.
Nice progress in increasing kite determinism & reliability
A foundation for better actuation by refining inherent sability into high performance elements.
& micro-meteorological insights into dynamic natural windfields (particularly rogue helicity)
Spread the word about autokites in austin to any kite freak techies. eventually i'll be back & pitch the field to the UT aerospace dept, an old haunt, the tinfoil capped propeller-headed kids will love it...
A major center of the recent emergence of modern kite sports. The Columbia River Gorge is KiteBoarding Mecca, a cradle of kite-sports. Gorge gap winds are a grand high-speed wind-tunnel. In fact, the outdoors is the best wind-tunnel generally. By waiting & searching for different winds in a diverse fluidic paradise like the Columbia-Pacific area, one far exceeds any lab set-up.
Fundamental patterns emerged-
During the preliminary 2007 endurance research the major causes of kite failure were, in order, dying wnd, wind helicity , high wind, pilot error, & gear failure. The last two were common on launch & retrieve. Helicity is worst near the bottom & top of wind range & near the surface.
Vortex-Handedness is Key- Winds in the Northern Hemisphere are most helical in the leading right quadrant of a westerly travelling Low, & to a lesser magnitude the trailing left quadrant of the adjacent High to the SE. This agumented helicity, facing the wind, turns counter-clockwise. So a kite is most likely to be hooked into the surface on the right window edge. An appropriate precaution is to fly the kite higher & more downwind, away from the probable crash zone.
Flying in hurricane force winds i realised the gustier a wind field, the more helical. Gustiness is helicity.
Lapse Rate crudely predicts micro-bursts, falling masses of air produce a surface wake of "book-end" vortices worst downwind of prevailing wind. Virga/white-squall effects can kill a kite on an otherwise fine conditions.
A Kolmorgorov turbulence spectrum histogram derived from wind/time sequences reveals basic flying conditions. Spikey spectrums warn of stong helicity across a wide wind range. If windspeed allows, a kites altitude is adjusted higher above bad helicity that literally flies the kite into surface, generally on a falling barometer.
Vortex spectrums consist of large scale helices with retrograde secondary helices forming between them like roller bearings. Large helices, unfed, decay into progressively smaller weaker helices. Smaller helice regimes form near friction surfaces & pass helicity upward.
A balanced stable kite shows wind-field helicity by leaning (yawing) according to weather & local effects. Many a frustrated kite designer has uselessly recut & rebalanced a sound kite that was never to blame for lopsided flight.
One can detect the same patterns on the micro & meso scales as on the hemispheric scale.
Lift was first understood as air hitting a wing, then as a low pressure Bernouli lift pulling on the upper wing. A proper wing uses both kinds of lift in proportions that vary according to flight mode. Swept wings transition lift modes smoothly.
Portland's park system tested of elements in flukey winds, to be more severely trialed on the coast & even up Mt. Hood. Storm kiting on the coast featured normal winds in the 100+ km-per-hour range. Ultimately the concept deltas flew well in gales, although one had to fight rogue helices from locking-out the kite. KiteMotor1 flew in 30 kt gusts without damage.
It was priviledge to meet Peter Lynn at KiteShip over a couple of days. He has the big picture of world technical kiting & confirms- big things afoot.
Portland's own, Wayne German, kite visionary. I just hit town from collaborating with KiteShip (kiteship.com) in CA.
I teamed up with eccentric Portland visionary, Wayne German, a savant humped by CRT introspection into a small buffalo. He dreams the future while abiding as a janitor & better deserved the "genius" prize more than SG. Wayne was inspired by my old work on the Net (esp. the sailing toy that screws itself directly upwind, a foundation for current devices) & was disoriented when i showed up in person.
Interesting prototypes, at roughly 60th scale, (including "free-flight": sustained flight of opposed kites across wind gradients) & renewing standing contacts in the NorthWest; at the University of Washington, Boeing engineers, the Drachen Foundation, & so on. We are sparking-up a PortlandKitebot Group to mirror similar groups now forming in Austin (my home), Seattle, & the Bay Area.
The kite energy prototype turbine is hand-carved/sanded foam blades with carbon rod & tape load paths and a PVC root, hand-sanded, skinned with nylon, very cheap & light compared to what Wayne thought was wanted, solid alu COTS turbine blades, giant swords really. rated for years of duty at near supersonic tip speeds, frightening if they flew loose. The biggest worry was the moving power loop but it worked.
Separating the lifted turbine & lifting kite functions was key, that weight-to-watts of the turbine end counts for more than raw rotor disc efficiency that has driven terrestrial wind-power design. A lighter yet smaller turbine with lower L/D may beat a more massive rotor by flying higher, starting sooner, & finishing later.
flying wind is 50-70% of time in normal "good" places (& at altitude above inversions), here on Pacific NW coast (best on continent) flying wind around 70% (at surface), very cloudy but winter nights very long, bad solar but lots of wind-power
Wind map below shows how NW coast is unique in N. America for year-round great winds, about 70% usable, a surface rate comparable the high altitude winds elsewhere.
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