Point of Influence and Feel
If you sight down the flying lines, you can mentally project the end of the lines to a point where they would intersect with the sail. This is known as the Point of Influence (POI) of the bridle. Typically on a conventional stunt kite the POI falls somewhere in the centre of the outer panel of the kite (the panel between standoff, wingtip and nose). This is roughly the area shown as in green on the following diagram.
There is a sweet spot somewhere roughly in the centre of that outer panel, roughly in the middle of that green blob. As your POI moves away from that sweet spot the feel of the kite will change. Feel is very difficult to describe but one of the best analogies I have heard compares the feel of a bridle to the feel of moving a record on a turntable with your finger.
Imagine a record on a turntable:
If you place your finger out near the edge, it is easy to turn but for a fixed distance travelled by the finger the angle rotated by the record is fairly small, it is also easy to accurately control how far you rotate it. The motion will however feel gentle and less snappy and a rotation takes comparatively larger hand movements.
If you place your finger near the centre, it takes more effort to initiate the turn but for the same fixed distance travelled by the finger the angle rotated by the record will be much larger, it is however more difficult to control the rotation accurately. The motion will feel positive and snappy and a rotation takes comparartively smaller but more accurately controlled hand movements
On a kite, where the POI falls outside the sweetspot, closer to the leading edgeyou will get the feel described in the first case: Hand movements will be larger, turns will be easy to start but it will not feel as sharp. On a kite where the POI falls closer to the spine than the sweetspot you will get the feel described in the second case: Small punchy hand movements, sensitive and sharp feeling, some initial reluctance to turn followed by a tight turn for comparatively little hand movements.
Comparing this with popular styles of kites there are three predominant styles of bridling which are popular. Looking at the diagram above, the POI falls roughly in directions A, B or C.
Beginner kites often have a POI roughly somewhere along line A, this gives steering somewhere in the middle but sets the bridle fairly light making takeoff easier, flight is generally fast and the kite can shed some wind when flown in a gale by a kid on a beach.
Current French Style kites usually have their POI somewhere along line B. This sets the bridle pretty heavy for good pitch based tricks (more on pitch later), sets the bridle wide which helps backspins but since this is analogous to having your finger well out on the turntable, hand movements can be very large and rotational moves such as axels and 540's can be sluggish compared to trick kites from the late 1990s.
Late 1990s British trick kites typically had a POI somewhere along line C, not much good for backspins but the short inhaul was like having your finger closer to the spindle on the turntable, rotational tricks like axels or the 540 were very snappy and turns crisp verging on oversteer.
Naturally these are very broad generalisations and many kites were quite close to the sweet spot or fell between styles.
Armed with the generalisations above it should be possible to take one of the rule of thumb bridles described below and adjust it roughly in one of directions A,B or C to start working toward the kind of feel you are looking for |