Kite Origins, written 2005

George Pocock, the acknowledged father of kite traction, made a good start with his patented controllable traction kites in the 1820- but even after 175 years of development, traction kites are a very long way from being 'perfected'- actually they're still barely useable (and not yet competitive) in comparison to conventional sails. The reason they have taken so long to develop to a state of useability that has enabled the development of a (minor so far) market is because there are so many performance factors that all have to work at the same time.

Yes, we need good upwind performance- but we also have to have luff resistance, crash resistance, launchability, packability, buildability, etc., and now, power control- the list is endless. So much complexity, so many possible ways to do things- at least we can be sure that traction kites will continue to improve for the foreseeable future.
But traction kite design and development is comparatively easy because the aerodynamic principles underlying steerable kites are relatively well understood- even while being difficult to apply in practice.

 

Counter-intuitively, single line kite design is much more difficult- I would say, to a first level approximation, that it is still not possible to design a new style of single line kite from scratch with
any real hope of success- even though the first single line kite probably flew as long as 10,000 years ago! What we can do is make a guess, play around endlessly with minor changes- and sometimes succeed- but not very often. After 35 years working full time in this field, I still have no useful understanding of why kites fly, or rather, why they don't fly- their overwhelming preference. Sure, there's one underlying principle that's certain - that kites are pendulums- but what it is that makes any particular design stable is a mystery to me- and everyone else too as far as I can see. Sure we have favourite things to try and endless half-baked theories that work fine until they really need to, but there's no coherent understanding.
It's no mystery as to why it's all a mystery though- the stability of single line kites is an interplay between the discontinuous aerodynamic effects of turbulent flow and the weight force - creating a complex feedback dynamic which is stable for only a few of it's zillions of possible manifestations.
The real mystery is how kites ever came to be invented at all.
The best aid to invention is to know that something is possible- and for kites there is no equivalent natural example. Birds inform the aeroplane, but nothing that I can think of heralds the kite.
Invention is also assisted by the existence of an incremental path- rather like the way that evolutionary mechanisms eventually created the eye.
For things like boomerangs, a development path exists. Over many thousands of years it could be noticed that a bent stick throws more easily than a straight one, even better if it's flat in the plane of the kink. Then, if it's warped a bit- as some bent flat sticks are sure to be, then sometimes it tends to fly in a curve- and so on to the returning boomerang-examples of which have now been found from more than 7000 years ago.
Similar paths can be postulated for other complex human artifacts; spears, knapped flints, throwing sticks, bows, needles, fishhooks etc.
I can think of just one likely path to a kite. In Southwest Asia (Indonesia in particular), a small percentage of one particular type of leaf, when dry and correctly bridled, will fly as a kite. Is it possible that there was a reason for tying fishing line to these leaves- like that the wind acting on such a leaf thrown onto the water would pull the line out? Maybe then, of all the possible points that this line could be attached at, at least once, the line attachment was within the few millimeter range that allowed the leaf to function as a kite- and that this happened with one of the few leaves out of many that was symmetrical enough and correctly formed to fly as a kite- and that it did fly- and that it was recognized as a kite- and replicated!
Yes, it stretches credibility, but what other explanation can there be?
Which gets me to the point of all this: What if kites were only invented once, ever, and that all the kites we now know, are derivatives from this by incremental development, spread by migrations and technology transfer to all the corners of the world that have a history of kite flying.
The only more likely hypothesis is that they were never invented at all- and we know this is not true.
This 'single origin' theory rests on two premises:
One; that from a probability perspective, kites are unlikely, to say the least, and are even more unlikely to have been discovered when it wasn't known they're possible.
Two; that no-one familiar with the field that I've talked with so far can come up with an obvious challenge based on known kite history. Both of these premises can be tested further.
If 'single origin' survives this testing, then 'reverse engineering' may well provide information about migratory and trade contacts, and their timing that is not currently known.

 

                               Peter Lynn, Ivanpah Dry Lake, Nevada, USA, 2 April '05.