Duotone Diversity Magazine No.02 2020

loops (attachment points) and the front pigtails; these are now one-tenth the weight of before with the identical tensile strength. They had to be indestructible. Yet, we haven’t had a single pigtail break in ten years. Thus, we decided they were over-engineered. A few things that really inspired us have been standard practice in the paragliding industry for many years. But there are also many other provisions in the manufacturing process: How is the leading edge sewn? Which tapes and webbings that were specifically developed for us have been used? Which reinforcements on the kite that cannot even be seen from the outside? A lot of this wouldn’t be possible if we weren’t so innovative in our production and developments. That’s where our enormous experience pays off. TILL A kite consists of about 500 individual parts. Lightweight construction means that each and every single part and how it’s integrated into the kite is meticulously designed and tested. And I mean, each and every single one. If you can save only one gram on each piece, you save 500grams overall. That’s no rocket science, however, it’s an enormous amount of work to check each piece systematically: Can I source another material that’s a tick lighter without compromising strength, stability or rigidity? And if a single measure seems promising, you still have to decide if it’s actually feasible to implement it. RALF But some aspects of the ULW just simply don’t make sense for series production: Pushing the limits with the ULW implied for example that I specified certain lines that were as thin as dental floss. You obviously couldn’t touch them without worrying cutting your hands. It’s vital to find the golden middle ground and not go too extreme – plus, you must never forget what’s proven and practical for everyday kiting. TILL By the way, also the 2020 Mono has the lightweight construction kit implemented and is therefore 15% lighter than its predecessor. It’s constructed with all the features of the Juice as well as the 140 gram Dacron canopy. Thus, it’s not only lighter, but also stiffer, which is particularly important for a one-strut kite. Don’t these lightweight measures have a negative impact on durability? TILL That’s a crucial point. All the aspects of our lightweight construction kit were tested under permanent load in practice and then approved. The lightweight kites had to go through the identical testing protocol as all other kite models in our range. Introducing new materials to the market usually is a lengthy process. We need at least one year from being presented with a new material to verifying it. Then we make the first, the second, and further 30 kites, which go for long-term tests to schools and team riders. If everything runs smoothly in this process, we ask ourselves: What exactly should we use this material for and what’s the availability with the manufacturer? There goes another year until it finally goes into production. Smaller companies that don’t produce the same volume as we do are most probably somewhat quicker to implement new materials. But they also take a higher risk. We simply cannot afford any mistakes. Let’s just think back to the Best Hellfish. With the Cuban Fire they risked a lot. Unfortunately these kites didn’t last. RALF When we receive a new material from a manufacturer, which has passed their testing protocol successfully, our work is only just starting. We have to take everything into account: What’s the product quality like? Does it lie nicely flat to sew? Does it shrink when sewn up? What’s its impact on flying characteristics? If it’s too stiff it could suddenly stop the kite from turning. A certain seam technique might work brilliantly for one material, but not for another. Only once it’s manufactured and tested in reality, it becomes clear if the innovation of a new material is worthwhile pursuing. Do technological innovations and a reduction in weight automatically translate into a price increase? TILL All the diverse construction measures with the new 2020 Juice lead to a 5% price increase compared to last year’s model. It’s like that in all other sports too: the lighter the equipment, the more expensive it gets. A super light carbon bike is dearer than an aluminum bike. An innovative lightweight-touring ski is more expensive than the identical, heavier all-round model. The more technological you go and the more elaborate the construction gets, the pricier the materials and ultimately the end product becomes. At Duotone we strive to offer everything to our clients that makes sense and works in practice. 10–20% of all our clients want the best of the best – regardless of the price tag. The most interesting area, however, is where you offer materials that are strong, light and stiff and thereby achieve a ULW CONCEPT the air that’s contained in the chambers has to be accelerated, which can be up to 1.6kg in the bigger kite sizes. Therefore soft kites are significantly heavier when up in the air than the ULW although their weight on the scales is identical. The ULW takes momentum out of the radius in the power zone, which allows you to get up on the board. It’s crazy: You only need one or two knots more wind than for simply launching for the kite to fly amazingly stable and to get going on the Foil Board. Is an ultra light kite only relevant for advanced riders who have the technical skills to kite foil in such light wind? TILL It’s not about the actual foiling part, but rather about getting up on the board. Ralf’s four knots in the ocean translate to about eight knots at my lake-home spot that’s at a higher sea level here in Bavaria. My problem with any traditional kite is that it just falls out of the sky in super light and often gusty wind. It’d be fantastic if in the future the kite would stay in the air even when the wind dies down. Even if I can’t stay up on the board, but at least swim around with the kite flying, that would change things immensely. All I’d need to do then is wait for another gust that will pull me back up on the board. Handling a soft kite really differs to handling a tube kite. With a tube kite you fly two or three sine curves to accelerate it, whereas with a soft kite accelerating is done through sheet and go. The soft kite might have a slight performance advantage once you’re riding, but to actually get up and get going is more difficult. How about normal Twintip riders. What’s the effect of such an ultra light kite for them? RALF The handling of such a light kite is super interesting when riding a Twintip. The lighter the kite, the more intuitive it feels. That’s because less weight equals less lifting work. Or let’s put it this way: Flying it in light wind feels just like if you were using it in stronger wind. Generally speaking, the less wind you got to play with, the more important it is that the kite is light. From a purely physical point of view, it’s very simple: The less mass you have to accelerate, i.e. the lighter a kite is, the better it comes up in the wind window and performs direction changes. On a Twintip, like for example the Spike Textreme, I can get going with the 15m2 Juice production kite in about 8 knots in Egypt. TILL Bikes, cars, even people accelerate easier when light in weight. A lightweight construction benefits the larger kite sizes the most due to considerable weight savings. But lightweight construction also makes sense for kite designs that are aimed at having fast-turning characteristics as less mass has to be accelerated in every single movement – like for example in flying the kite up and down or looping it. In our tests, we determined that lightweight construction has a substantial impact on big kite sizes down to 9m2. In the smaller sizes, thus 8m2 down to 4m2, the turning speed increases naturally and this lightweight construction-advantage disappears. Popular sizes such as 13m2 or 12m2 in the light construction feel like a traditional 10m2 or a 9m2 would, and that’s a pretty sensational feeling. Do lighter kites have a lower high-end? RALF That depends on the material and the structural stability. The ULW is structurally less stable, thus cannot absorb as much wind as a normal series production kite. TILL That being said, it would be different with a production kite made of new and refined materials. That’s something that could be really exciting in the future, as the entire wind range of that kite would increase. It would not only start earlier, but also accelerate easier through less mass and thereby turn faster yet still stay stable and easy to control even at the higher end of its wind range. However, from a certain wind strength onwards, let’s say about 25 knots, the lightweight construction doesn’t offer any significant advantage. Which insights from the ULW concept are currently incorporated into the standard production to make standard kite models lighter overall? TILL Let’s take the Juice. From 2018 to 2019 we changed the cloth of the canopy from 160 grams to 140 grams that brought about a 12% weight saving. For the new 2020 Juice we adapted a lightweight construction kit from the ULW concept, saving an additional 12% in weight. Comparing that to an Evo in the same size, the 2020 Juice is 25% lighter, which is rather significant. Just imagine how your bicycle would feel if it was 25% lighter? RALF In precise numbers, that means for these kite models in 13m2: ULW 1.95 kg, 2020 Mono 2.89kg, 2020 Juice 2.97 kg, 2019 Juice 3.35 kg, 2020 Evo 3.75 kg. What exactly does the lightweight construction kit that has been implemented into the series production mean for the new 2020 Juice? RALF The lightweight construction kite comprises many details, which also have a positive impact on the aerodynamics: We use for example a new material for the bladders and thinner bridle lines. We also saved considerable weight on the T E C H N O L O G Y 82 83 T E C H N O L O G Y I N N O V A T I O N