Lines
From KiteWiki
Kite lines are usually supplied in pairs or in sets of four depending upon the type of kite they are suited for.
They are made of a material that has high breaking strain and low stretch. Examples are Dyneema and Spectra.
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Breaking Strains
For stunt kites and sports kites, breaking strains will be quite low, usually less than about 40kg per line.
For power kites, lines will be considerably stronger, typically arranged as 180/110 (meaning 180kg power lines and 110kg brakes) or around 225/100.
The line strength used does not depend on the size of the kite being used, but what it is being used for (basically the weight of the load that it will carry which could be you and your buggy, and the acceleration that it will be subjected to, which makes you effectively weigh more).
For depower kites and for fixed bridle kites used for buggy jumping, 360/360 is a common combination.
Line Lengths
Line lengths for general use
New fixed bridle kites sold as ready to fly or RTF usually come with 25 or 27 metre lines as standard.
Line lengths for inland flying
Longer line length to 30 or 40 metres can be useful as it gives an increase in power (as the wind speed is generally higher further up) and can provide more clean wind as the height avoids turbulence caused by nearby trees, buildings, sand dunes (yes Sand Yeti) and ground effects. Longer lines also mean that the kite travels further in an arc before needing to be turned, so you can develop more power across the wind window.
Line lengths for buggy racing
Shorter line lengths of 15 or 20 metres are often favoured by buggy race pilots, as they give more responsive control of the kite, and allow pilots to fly closer together without interfering with each other's air space.
When flying race kites, you are looking for speed not lift, so you keep the kite fairly low to the ground, hence longer lines will only put the kite further away from you and not into cleaner wind (plus the lines introduce drag as well) so there are few advantages to having longer lines. The only exception is when turning the kite where longer lines give you more room to e.g. to downturn a large kite, but they also give a slower turn, as the kite has to move further through the air before the angle of the lines and kite changes with respect to the buggy position.
As an example, consider a 14 metre race kite on 10m lines. If doing a 180 degree turn on a reach, it will move through an arc of say about 12 metres before it is powering the buggy fully in the opposite direction. If the lines were 25m, it would have to travel an arc of say 30 metres before powering the buggy up fully, and since the kite would fly around the arc at about the same speed, it would take more than twice as long to complete the turn
Maximum flying height
Note that CAA regulations do not permit kites to be flown at a height of more than 60 metres.
Sleeving
Lines are usually sleeved with Dyneema sleeving at the ends to reduce wear and make it possible to loop the ends. The looped ends make it easy to attach the lines using a larks head knot.
See Re-sleeving for details of how to re-sleeve lines that have broken or stretched.
