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Here we have Arnulf's drawing for the athwartships rail system

Kite track.JPEG

Here, then a photo of just such a system, installed longitudinally, on a proa. Note that the flying lines pass through turning tackles at the end of the rail, as with Arnulf's, thence down to a second set of blocks, near the outrigger. On the proa, this let us effectively attach the kites at the ourtigger rail, rather than at the main hull. For best performance, there should be yet a third set of blocks, near amidships, on the outrigger. This so that the kite force will be attached to the boat at a single point on its structure. This system (with only 4 blocks) had too much friction, even with carefully constructed bearings. Other shortcomings of this system were given in my earlier e-mail, reproduced here:

"I abandoned this rail system, for several reasons. You may be more fortunate: Whenever you want to steer the kite, you must shift the entire winch along the rail. It is heavy, demanding very good bearings, and even then, it has much inertia. Also, sometimes, especially with Chevron-type kites, the differential between line pulls is very great. You will have to hold this, without mechanical advantage, or the reel will run to one end of the track and the kite crash (if you add mechanical advantage, as with block and tackle, you cannot steer the kite quickly, and will likely crash). Also, when the line is wound onto the reel, sometimes it winds unevenly, and the (shortened) lines are different lengths. This means that the reel must be near one end of the track, just to fly straight. If you need to move the reel towards the "short" side, to correct the kite's flight, you will "run out" of track, and the kite crashes."

And also his schematic for launching from a catamaran.

Just as a bonus here are two photos of "inflatable" Flexifoil kites. This was done by constructing and inserting individual Mylar bladders into each cell in each kite. The purpose was to "pre-inflate" each cell, so that the kites would hold their shape, both in low wind and on the water. The "bowstring," seen in the upper photo was to eourage pre-bending of the spar. All this to enable a Flexi stack to self-launch, from water. The concept worked, after a fashion. We could self-launch a single kite, but not a stack. Re-launch, after a crash, was never possible. The kite(s) usually land upside down, and cannot be re-righted from a distance. Also, tangled kites and lines in stacks were impossible to avoid. We learned to make a single launch, and simply never crash the kites!

There is too little volume inside a Flexifoil kite to consider helium inflation, though we are working now (Spring '97) to do this with larger kites. (See also Keith Stewart and Theo Schmidt's work in the 1980's with helium inflated kites)

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