Stunt kites vary less in design and materials than single-line kites, as they are designed to entertain not by their static form but by the form of their flight. With this single aim in mind, the design of stunt kites has reached its height with the creation of the delta shape wing with a high bridle and curved leading edges.
Sport kites are ‘delta kites as they are almost triangular in shape. They are typified by a single spine and have a high aspect ratio (AR), meaning that they are wider than they are long. They generally have a high bridle and curved leading edges. When choosing a sports kite, take into consideration that there will always be a trade-off between stability and manoeuvrability; what you gain in one you will lose in the other. Essentially, a more precise and stable sports kite has a lower AR, a wider nose, a longer spine below the ‘T’ (the centre of the kite), straight(er) leading edges, a larger billow (sail depth or slackness of sail) and a longer bridle placed nearer the spine and nose of the kite.
The opposite end of these variables will obviously produce a more responsive kite which can perform advanced tricks.
Two more important design features of a sports kite are the shape of the wings and the wing tips. When the wing tips are narrower and pointed at the end, and the trailing edges of the kite are significantly cut away, the kite is able to turn more quickly. The wing tips may also be twisted inwards, to resist stalling.
For optimum flying, the kite should be as lightweight as possible, but as big as possible so that it will be stable in light wind. Obviously the bigger the kite, the heavier it becomes, especially with the spar weight, so there is a trade-off and an optimum kite size. This relationship can be calculated in an equation of weight divided by area, the result of which is called ‘wing loading’. The lower the wing loading, the less wind it will take to launch and fly the kite. The standard 2.5m (8ft) stunt kites generally achieve optimum wing loading.
There is a variety of methods of holding on to a stunt kite. Simple spools can be used, but the more popular choices are either padded wrist straps or bar-type handles. The strength and length of lines you choose depend upon the size of the kite, the strength of the wind, and if you want to get very serious on whether you want a more responsive kite which will be unforgiving if you make mistakes, or one that reacts more slowly but gives you more time to perform your tricks. Line strengths are often given in terms of their ‘breaking strain’. A kite with a breaking strain of 90kg (200lb) is on the stronger end of the spectrum and could be used in stronger winds and/or with bigger kites, whereas a line with a breaking strain of between 45kg (100lb) and 70kg (150lb) is about average. Lengths of line for sports kites are between 20-40m (65-130ft), these days usually sitting around the 25m (80ft) mark, with shorter lines used for indoor kiting or congested areas, and longer for Stacked kites.