Single Line Kite Stability
Published: 01 Jun 2023
I've been trying to understand why kites don't fly, ever since, as a smartarse young engineer, I expected to set the world of kitemaking to rights in short order when I made a kite for our first child in 1973. Ah, hubris! It didn't fly (of course)- setting in motion a life-long obsession with kites that has left my long-suffering wife in despair at times, has had a few successes, but hasn't produced the coherent, predictive understanding of single line kite stability which I thought ...
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Single Line Kite Stability Factors
Published: 01 Jan 2013
Single Line Kite Stability Factors1. Centre of pressure position relative to centre of gravity as a function of kite size2. Aspect ratio:3. Line length; relative to kite size4. Bridle type- longitudinal and/or lateral- and length relative to kite size5. Kite's weight/area ratio6. Lateral area; as a function of lifting area.7. Late...
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SINGLE LINE KITE STABILITY, to October 2012
Published: 03 Oct 2012
SINGLE LINE KITE STABILITY, to October 2012. Contriving an object that, solely by the relationships between its lift, drag, weight and line attachment point, can maintain itself at some elevated station in the centre of a wind stream seems likely to be difficult but maybe not impossible. That it should also be able to do so at every line angle from zero to nearly 90 degrees and in every wind from a whisper to a swirling gale is a hopeless fantasy - except that such things do exist- they're ...
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Commentaries on Single Line Kite Stability
Published: 30 Nov 2010
Commentaries on Single Line Kite Stability1. Delta style wingtip drag-When flying at apex, with low angles of attack (when pendulum effect is least), there is no lift from tips, just drag- this is a progressive stabilising effect. I tried this on a prototype ray (building in twist to the wingtips so as to reduce their angle of attack relative to the centre sections)- but the wing tips luffed and folded, required strong steady wind to hold them back. Will next try reflexing tips rathe...
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Under-correction/over-correction
Published: 01 Dec 2009
Under-correction/over-correction.- Bintulu '09Does under-correction merge into over-correction with no stable point between- that is , as the kite under-corrects and traverses to the side, at a certain rate of doing this the correction builds into violent figure eighting. Could the stable point be at MUCH faster correction, rather than between under-correction and over-correction?A test could be a square diamond shaped kite (polystyrene?), with tip drag for stabilising (small wind socks), ...
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The Main reason why single line kites (often) don't fly.
Published: 01 Jul 2009
The Main reason why single line kites (often) don't fly. It's because kite stability is sensitive to angle of attack, the angle at which wind strikes a kite's surface(s), and angle of attack (called A of A from now on) varies widely with line angle and wind strength.Specifically: A of A is high- close to 90 degrees even- when line angle is low (while launching for example) and also when there's barely enough wind to keep a kite up. A of A is low when a kite is flying at hig...
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Why kites (don't) Fly- Single Line Kite Stability.
Published: 01 Apr 2009
Why kites (don't) Fly- Single Line Kite Stability.For a kite to fly on a single line, it must, as the most basic condition, have some way to detect which way is up. All single line kites that aren't under some sort of remote control do this by having their centre of lift position (CL, where lift forces act) above their centre of gravity (CG, where weight forces act)*. This pendulum effect causes such kites to point upwards, and upwards they will fly, until they get to a line angle at ...
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Even More Reasons why Kites (don't) Fly- Single Line Kite Stability.
Published: 02 Mar 2009
Even More Reasons why Kites (don't) Fly- Single Line Kite Stability. There are a large number of effects that influence kite stability (or more usually the lack of). January '09's Newsletter described some fundamental ones. Here are some more: The approach in "Why kites (don't) Fly- Single Line Kite Stability" was to consider effects from the perspective of how a kite responds when its axis becomes misaligned with the wind direction. Optimally, kites should neither un...
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Single Line Kite Stability
Published: 01 Dec 2008
Single Line Kite StabilityFor a kite to fly on a single line, it must, as the most basic condition, have some way to detect which way is up.All single line kites that aren't under some sort of remote control do this by having their centre of lift position (CL, where lift forces act) above and forward of their centre of gravity (CG, where weight forces act). The pendulum effect that this creates causes such kites to point upwards, and upwards they will fly, until they get to a line angle at which...
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Single Line Kite Stability: Sept. '06.
Published: 01 Sep 2006
Single Line Kite Stability: Sept. '06. Why kites can fly is such a complex question that after a first rush of youthful overconfidence in the '70's, I've despaired of ever finding useful answers- that is, useful in the sense of predicting, for known or intended kites, what effects given changes will have .But recently I've been thinking that many equally complex problems are understood to a useful extent;What do I actually know? - not necessarily to the standards required for mathemat...
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Stability Considerations for Single Line Kites
Published: 01 May 2004
I started writing this in 1973 but found that understanding why single line kites fly (or rather, why they don't fly) was more difficult than I thought it would be. Kirri (eldest daughter) enjoys reminding me that my life's goal then was to have the field pinned down by the time I was 35. Now 57, I still don't have a very good understanding; not quantitative, not able to predict by how much something has to changed by to get a defined effect- yet!. However, I'm now quite often able t...
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This I Know is True, Maybe..
Published: 01 Jun 2001
This I Know is True, Maybe..(Some Ideas About Single Line Kite Stability) Kite stability is enabled by contriving a kite's C of G ( the notional point at which weight forces act to pull it downwards) to be below it's C of L (the notional point at which aerodynamic lift forces act to lift it upwards). This is the primary requirement, in the absence of which sustained flight is not possible. There are, however, many other relationships which to varying degrees contribute to or...
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