Where Next?

Some random thoughts on kite design. Written at some obscene hour of the morning, after a beer or several. This document is likely to be misspelt, grammatically poor, and most likely wrong. Enjoy. Posterity, or more likely Peter Lynn, will probably mean this document makes me look like a twat.

As I see it, the goal of designing traction kites is to design a user friendly kite that pulls like a bastard. Not just downwind, but all the way through the window and right to the edge. And beyond. Now, by 'user friendly' I don't mean 'something we can give to any idiot on the beach', or 'something that is easy to fly' - I mean 'something that is predictable'. 'Friendly' as in 'won't suddenly turn round and bite you in the arse'.

What do we need for this?

Well, good all round performance is one thing. I could go and build a trident tomorrow, have something prety awesome. In fact, I may do that.

But. For me, ultimate performace is a big pain in the arse. At least with the current breed of powerkites, and I include all my own current designs in that group. Because wind range for kites is very limited. If the wind lulls, my 5m kite is absolutely no bloody use whatsoever. Similarly, if it suddenly jumps, I'm totally overpowered, and brown-trousering. So, I need to carry a 1.5m for stupid high winds, a 3m for high winds, a 5m for medium winds, and a 7-9m for those 'shite, I'm half way down the beach, no wind and it's a 2 mile walk to the car' moments. Hmmm. What can I do about that? Well, spreading the wind range either means detuning something massive to up it's maximum, growing balls the size of melons, or rethinking design.

And I have. I went to Weymouth kite fest this year, and met up with John Travell, who has a very interesting slot effect single skin kite. Very interesting indeed. And it got me thinking.

A while back I saw a foil designed for maximum low speed lift. It looked like a venetian blind. All thin slats and big gaps. It's been simmering away in the old grey sludge for a while, and seeing John's kite made some of those thoughts coalesce.

What if we could have a kite that pulls bloody hard at the edge, but whips across the middle of the window without pulling you out of your boots? What if we could have a kite that could be tuned on the fly, without even landing it? What if the kite could be flown to pull hard in one wind range, but if the wind doubles or triples the kite could still be flown?

Now, this has been possible for some while. Take a big mother kite, sling 2 primary bridles on it, and adjust between the two on the fly. Andrew Beattie did it with the reefing Chevron when I was still playing with flexifoils. His was even automatic. More recently, Gene Matocha proposed a system for adjusting kite characteristics at the handles.

Both of these systems would allow you to fly a conventional kite in higher winds by detuning it.. I propose rather than detuning a conventional kite, we should be 'uptuning' a smaller kite. We could run smaller kites, which are faster, weigh less, accelerate harder, handle better, blah blah blah. How? Slots is one way, and as that's the current bee in my bonnet...

As you should know, most of the lift generated by a kite is made at the leading edge. First 25% of the profile, and all that. What you may not know (but should, intuitively) is that slapping a second foil in close proximity to the first generates more lift. Something to do with putting the second foil in the wake of the first. Planes have been doing it for years, they are called 'flaps' and 'slats'. They have gaps between them. The slats and flaps are in effect separate mini-wings.

So, I propose taking a couple of kites made with high performance foilshapes and nesting them. The resulting foilshape is the 'low performance' or 'high wind' setting. Pull them apart, and the two foils not only start generating lift independently of each other (we have doubled the effective leading edge) but also interfere with one another to make even more lift. This is the 'low wind, high performance' setting.