Trimming a light weight glider is much the same as trimming the full fat alternative. Many light or semi light wings have the exact same line sets as the heavier version and of course some are stand alone wings in their own right but are almost always fitted with a standard, unsheathed line set that has the same trim issues as those of a normal glider.
Most of these light weight wings have thinner fabric incorporated into the top and bottom skins and some use light weight risers as well. These two design traits give a significant weight reduction over a normal weight wing. One part of the design that is often overlooked is the use of plastic rods in the wing. Gliders that have full length plastic rods can rarely, if ever, get close to the 3.5kg mark in the small or MS sizes. These wings are usually closer to 5 or even 6kg in the largest sizes. Despite the use of light fabric, we can hardly call these wings “light weight”!
The single issue we have when trimming these light wings is with the use of soft links, which I’m afraid are only fitted to most of these gliders as a piece of marketing hype.
As you can see in the images here, moving the glider’s lines from soft links to 3mm maillons comes at the expense of 25g, less than an ounce. As a comparison, the XC Tracer Mini III weighs 34g, and a pound coin weighs just under 9g – Hopefully you can see where we’re going!
Well the light links are beautiful to look at and when paired with a set of thin white dyneema risers, quite the part on a brand new X-Alps wing, but frankly look quite a bit silly on 12mm black webbing… but the big problem comes after about 50 hours or so when your glider needs its first trim check. Gliders that have some black webbing and some dyneema cord in the riser system are particularly prone to going out of trim.
Using maillon rapides, we can make trim adjustments between 8 and 12mm per loop depending on the thickness of the line we’re working with. With soft links, the addition of a double loop will shorten the line by around 18-20mm, which is usually not precise enough to put your glider back in trim. The other issue is the speed at which your glider can be adjusted, this isn’t a problem if you are sending it away to a specialist like us, but if you’re at a competition or on a trip for a long time and want a quick check one evening, you won’t be making any friends with the local trimming experts if you ask them to make adjustments as they’re incredibly fiddly to loop and refit to the risers! We also have the issue than when remeasuring, there is a certain amount of slack in the soft link and in the added loops that really will only be removed by flying the wing for a couple of hours.
The solution is very simple! When you send us your light weight glider, we can either trim it using the soft links that came with it (with the caveat that it cannot be trimmed quite as accurately), or offer you the option of having the lines moved onto 3 or 3.5mm Maillon Rapides. This is an inexpensive solution to the problem and will allow you to manage the trim of the glider far better over it’s lifespan. Some manufacturers, for example Air Design and Skywalk do not spec their light wings with soft links from the factory for this very reason. Ozone and Advance do, so usually these are the wings that we’re offering the service for. Someone who is interested in getting the absolute best performance from their glider shouldn’t worry about the extra ounce of weight on their glider, it will fly so much better, the smile will more than make up for having those extra three coins in your pocket! 😉