Andy Wardley
<abw@kfs.org>
To make a bridle stick, take a solid length of wood, at least a few centimetres wide on each side, and about a metre long (a little more than a metre is recommended). Mark a line (the "0-Line") at right angles across the wood and a few centimetres down from one end. Bang a thin nail into the wood at a point on the 0-Line roughly half way across the stick. Leave part of the nail sticking out of the wood so that loops of bridle line can be held around it. Measure down a metre from the 0-Line and mark another line across the stick (the "100-Line"). Bang a nail in here in a similar way to before. If your stick is less than a metre long, you might want to choose another convenient distance (75cm, 85cm, etc.)
Or, get a bigger stick.
A bridle stick can be marked with measurements for many different kites, but be warned how easy it is to get confused when you have 11 versions of 3 different bridles all on the same stick. You may find it useful to mark measurements for different kites in different colour pens or on different sides of the stick (if you don't mind banging in more nails and marking more lines). Mark all measurements with the name of the kite and the name of the section or mark that it indicates (e.g. "OSpace Upper Leg Activator Mark") and don't be afraid to scribble reminders or makes notes on the stick. You'll be glad of them when you come back to it a month later and can't remember what any of the markings mean.
The only problem with using unsheathed line is that knots are more prone to slippage. You may wish to add small overhand stopper knots in the end of the lines to prevent this, although you should remember to tie the knot at the required distance and then cut the line, rather than cutting the line and then tying a knot. The latter will shorten the overall length of the line. Where continuous lengths of line are joined, mark the correct position on the line with a marker pen, holding the nib in place to allow the ink to sink into the fibres of the line. The ink from the pen should provide enough friction in the bridle line to hold position as well as serving as a clear visual marker when assembling the bridle.
When measuring the line exactly (preparing the first end does not require
any such precision), cut the line about 5mm longer than required. Take
the line and gently tap the end with a finger to open out the braid.
Next, take a cigarette lighter and quickly melt the end of the line. As
the strands shrink back and melt, tap the end of the line against a hard,
fireproof surface. The metal surround at the top of a cigarette lighter is
ideal for this. Your finger is not.
This process should create a visible flange of hardened plastic which opens out at the end of the line. This is usually all that is required to stop the end of the line slipping through a knot. A little further melting and pushing can be used if required to shorten the line further to the exact length.
We have so far been unable to solve problem of what to do when the line has been melted too short. :-)=
The connection of a bridle at the centre T-Piece of the kite is usually
best achieved by doubling over a length of bridle line and tying a simple
overhand knot around the doubled line. This creates a loop which will slip
around the spine of the kite (usually below the T-Piece). When tightening
this knot, it is useful to first slip the knot over a spar from the kite
in question (or one of the same diameter) to ensure that the loop is a
reasonably snug fit.
The two ends of the loop section will become the inner legs of the bridle on both sides of the kite. In the Active Bridle design, one continuous piece of line runs across the bottom of the bridle, from lower leading edge one one side, around the spine at the centre T-Piece and then out across the other side to the opposite lower leading edge.
When tying a Sheet Bend for the Active Bridle, you will be joining a
loose end of line, complete with a flange, onto a continuous section
at a given mark (which you should have pre-marked on your bridle line).
First, fold over the continuous section at the required mark to create
a loop. Feed the loose end up through the loop from behind, and down
back around the outside of the loop. Bring the end right around the
loop and then tuck it back under itself. The loose end should be
running under the part of the line pushing up through the loop, but
over the edge of the loop itself.
To tighten the knot, gently pull on the long end of the single section of line, holding the loop folded over at the required point with the other hand. Nudge the loose, flanged end in towards the knot and tighten until it lies snug up against it. The flange should prevent the end from slipping through the knot.
Take a section of bridle line a little more than double the required Tracer length (e.g. ~30cm for a 10cm Tracer) and fold it in half. Loosely tie an overhand knot around the loop, tightening it towards the free ends. Slip the loop over the nail at the 0-Line, and make the final adjustment to the position of the knot so that it lies directly over the specific mark (at 10cm, for example), and then pull tight. Cut the bridle line 5mm or so past the knot and flange the ends, in situ, with a cigarette lighter.
The loop end will be attached to the bridle with a Prussik knot (next section) and the knotted free ends will form the point to which the flying lines attach.
Take a Tracer loop and pass the knotted end behind the continuous length
to which you're attaching it. Bring the knot up and over the line and
then feed it through it's own loop end. Bring the knot back around and
through the loop once more and then pull the knotted end tight.
When the continuous length is pulled tight so that it straightens out when going the knot, it will allow the Tracer to slide up and down it. By pulling on the Tracer and holding the Prussik knot between one's fingers, the knot can be rolled back on itself (looking much more like a Reef Knot) to lock it into position.
The knot employed is a basic Running Knot with a flange in the line serving
to stop the tied end from slipping through the knot. The loose end is
passed around the back of the spar and then up and around itself. The
loose end is then tucked through the loop it has just created by doubling
back on itself. The overhand knot that has effectively been tied around
the long end should be tightened so that the flange on the short end lies
snug against the knot. The long end can then be pulled to tighten the
slip knot up around the spar.
Attaching the Bridle to the Kite
This method is strongly recommened when designing an Active Bridle for a kite from scratch. By leaving the original bridle on the kite, you have something to gauge your new bridle measurements against. The bridles can be held taut alongside each other to give an approximation of where the required connecting points should be on the Active Bridle. See the section below on "Designing and Tuning an Active Bridle" for more information.
When the Active Bridle has been properly configured and gives satisfactory results, the original bridle can be untied and removed from the kite.
Two marks are required on the bridle to indicate the connection points
for the Activator and Stabiliser section. These are known as the Activator
Mark and Stabiliser Mark and are both measured down from the end of the loop.
The lengths from the loop to these marks are known as the Lower Activator Mark
(LAM) and Lower Stabiliser Mark (LSM) lengths. The overall length of the
legs from loop to end is known as the Lower Leg Length (LLL).
The lower leg section is attached to the kite by passing the loop over the lower end of the spine and pulling it up to the T-Piece. The loose end are then fed through the T-Piece cutout from the back. The loose ends are tied, one to each lower leading edge spar, directly below the connector and above the C-clip, using the Frame Knot technique desribed earlier.
Two marks are made on the upper leg sections, both measured down from one end (the upper end). These marks are known as the Activator Mark and the Tow Point. The Activator mark will be roughly half way down the line. The Tow Point will be close to the lower end of the line. These lengths from top end to mark are known as the Upper Activator Mark (UAM) and the Upper Tow Point (UPT) lengths.
Attach the upper end of the line (furthest from the Tow Point) to the upper leading edge spar of the kite, directly below the connector and above the C-clip, using a Frame Knot.
Attach the lower end of the upper line to the lower bridle leg at the Stabiliser Point using a Sheet Bend.
Attach one end of the Activator to the lower leg on the Activator mark using a Sheet Bend. Attach the other end to the upper leg on its Activator mark, also using a Sheet Bend. The Activator leg should now connect the upper and lower legs, pulling them slightly in towards each other.
The section of the upper leg below the Tow Point has now become the Stabiliser leg.
Your kite has been Activated.
Permission is hereby granted for any person to use or modify the Active Bridle for any purpose, under the following conditions:
This document is © Copyright 1998 Andy Wardley. All Rights Reserved.
You may freely copy, mirror, print or distribute unaltered copies of this document, provided that no charge is made for it. Please contact the author if you wish to reproduce the document in a commercial publication or in an altered format.