NPWC 2 Line Bridle

While at Fanø, I setup the a NPWC v7 to fly on two lines. This has a few advantages:

Simple Bridle

The picture below shows the main idea: For each side of the kite, a long loop (red) is run from the top attachment point to the bottom attachment point of the kite. A short loop with knot (blue) is attached to the loop bridle using a prusik knot. The flying lines are attached to the knot on the short loop.

NPWC 2 line

The long loops I use are 5.25 m. After tuning, the attachment point was 280cm from the top canopy bridle point (245cm from bottom bridle point). I.e. the distance from the top attachment point is slightly longer that from the lower attachment point. The prusik knots allow easy adjustment of the attachment point, which could be slightly higher or lower depending on the kite.

Prusik Knot

The pictures below expand on creating a prusik knot loop to make an adjustable bridle. The pink line is the long bridle loop, the orange line is the small loop with kite line attachment knot.

Loop and bridle

Looping the small loop over the bridle one time creates a larks head knot. This is a great knot for many purposes, but it is not designed to hold a bridle setting.

Loose Larkshead knot

Looping the small loop over the bridle a second time creates a prusik knot. When tightened, this knot will hold the bridle setting quite firmly.

Loose Prusik knot

This is what the prusik looks like when tightend.

Tight Prusik knot

Closeup of a tightened prusik knot from the front and from behind.

Closeup Tight Prusik knot Closeup Tight Prusik knot behind

To adjust the prusik, pull on the pink line on both sides of the knot to straighten it out. The prusik knot may then be slid up or down the pink bridle line to adjust the AOA of the kite.

Adjustable Prusik knot

Remember to tighten the knot (so it looks like the previous picture) after adjusting.

Four Line Conversion

Once the proper bridling point for two line flying is found found, it is easy to convert this to 4 line flying on handles: Cut the pink line at the point where the small loop is attached, then tie knots on the cut ends for four line attachement points. Conversion back to 2 line flying is by using the small loop with a larks head to join the two lines on each side of the kite.

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©2007 Bill Ola Rasmussen