FITTING A REPLACEMENT LINE

Damaging a paraglider line can be so frustrating when you realize it needs to be replaced before you can safely fly again. And we all know that sending your glider to a service shop can become time consuming and quite costly. Especially when you consider that you will be paying extra for the line installation and shipping costs in both directions. Of course, this all can be avoided if you mail order the line and install it yourself. Paraglider line fitting is something that can be done by most pilots given enough time, space and patience.

While there are money saving and time advantages to this approach, there are three (3) pitfalls you need to become aware of. Note that it is best to read these pitfalls first and only review the underlined video links, down at the very bottom, if you still don't understand fully on what to do. 

1. THE FIRST PITFALL TO AVOID:

Make sure you name exactly which individual line segment is damaged or broken. To do this, just review your glider's rigging diagram (aka Line Map, Line Plan) in its user manual. Often you can download the glider's manual from the manufacturer's website. These rigging diagrams will denote a line designator or "line map reference code" for each and every individual line segment. However, double check your damaged line's location in relationship to the rigging diagram to be sure you obtained the correct line map code. Please keep in mind that the line map codes may use letters that are case sensitive, numbers and roman numerals. Be exact to obtain your correct lines!

2. THE SECOND PITFALL TO AVOID:

Before you replace the damaged line, make sure the new line's length is fitted, or looped down with an appropriate line loop, to match the damaged line's length you are replacing. To simplify this process, first, secure the risers. Then, secure the new line's end loop within the appropriate riser maillon or soft link (be sure to match the existing maillon loop on the damaged line) and pull the lines (side by side) by hand with equal tension (roughly 5 kg or 11 lbs.) to compare their lengths. Most of the time, you will find the replacement line is slightly longer than the old one (or corresponding one on the opposite side), then you should do the same as I would in the workshop and fit or loop the line down appropriately. The extra loops to choose from are pictured in the next section below. 

Note that all lines shrink unless the wing is towed up regularly or under power. Usually, the most shrinkage will happen at the beginning of a line's life span with the process stabilizing thereafter but continuing at a much slower pace. Dyneema lines tend to have noticeable shrinkage during their first 50 hours of use. Aramid (aka Technora, Kevlar) lines tend to have noticeable shrinkage at about 100 hours of use. However, both line types can shrink more than expected when exposed to water, ocean air, high humidity, extreme temperatures and even more when combining any of these.

Please know paraglider line fitting is not as simple as making a new line the same length as the old one. If I did that, it is reasonable to expect the new line will follow the same pattern as the original line. Meaning it will shrink the most in the beginning. In turn, which means the new replacement line, within the next 50-100 hours, will no longer match the existing line set that had already shrunk and stabilized. And, thus, the new line will need to be replaced again.

To resolve this inherent line shrinkage problem, when the glider has less than 150 hours of use, we make replacement lines at the original factory length, and you can fit the replacement line with a suitable loop at the riser maillon or line-to-line connection to reduce the factory length down to match the old line. Pictures of all the loops, to choose from, are in the next section below.

And, if your glider has over 150 hours, then, I take the existing line's length and add 5-10mm to it. However, you will need to measure the damage line or its opposite for me. Click on this underlined term for a video on, "Measuring to replace a damaged line".

For mid-lines or upper line replacements, you should not have to worry about the fit because these shorter lines shrink much less. However, if by chance there is a significant difference in length, then add an appropriate loop at the line-to-line connection. Lastly, at the next periodic trim tuning of the glider, the added loop(s) can then be re-evaluated and re-adjusted accordingly.

There are other types of loops used in this industry than shown below, but the ones denoted are the simplest to make and work on the riser maillons (shackles) and at line-to-line connections, as well. Note that the effect of these loops can vary. Examples are tandems, paramotor wings and risers with soft shackles (link lites) where the impact of any loop can be up to fifty percent more due to having larger diameters. Whereas smaller diameter unsheathed lines and/or thinner shackles will have a less effect.

Lastly, if you have a glider using Link Lites (soft shackles) for their line connections to the risers, we have attached Ozone's directions at the bottom for their line removal and replacement.

3. THE THIRD PITVALL TO AVOID:

After fitting the new line, double check that it is in the correct location and not crossing another row or line inappropriately. That is worth checking right after fitting the line and again when you inflate your wing next, as part of your pre-flight inspection, just before flying again.

Conclusion: Bear in mind that factories specify a tolerance of +/- 10 mm for overall line lengths from maillon to the surface of the wing, but that is primarily intended to allow for variation in lengths that arise in use, and not from manufacturing inaccuracies. For example, when I make a replacement line in the workshop, the standard is within 1 mm of specification. However, the factory tolerances show you there is leeway here if the replacement line differs slightly more in length.

CAUTION: Paraglider's line lengths change due to aging and external influences. Thus, I always recommend a trim tuning when replacing four or more lines.

VIDEO LINKS:

A. Beginners: Overall line repair process.

B. Main or lower line replacement video.

C. Measuring to replace a damaged line.

D. Adjusting lengths on new mid or upper lines.

E. Paraglider layout for line replacements.