We believe the D2 has proven to be the best selling EN C wing in the history of paragliding. But why? What makes it so special?
The D2 has a moderate aspect ratio of 6.05, a conventional 3-line design, and is known for being an accessible Sport Performance Class wing that has set new standards in the category. In addition to the patented OZONE SharkNose technology, one of the key developments incorporated in the design is the positioning of the A line attachment points. On the Delta series, they are located further away from the leading edge, and deeper into the chord. This makes the wing more collapse resistant, more solid, more stable, and more confidence inspiring. In general, it improves both real life safety / stability, and ease of use. This design decision was deliberate and is the direct result of our core design philosophy, which is to build wings that perform in real conditions.
Although more stable and comfortable, in real-life collapses, the Delta2 behaves similarly to any other wing in its class. In fact, due to its relatively low aspect ratio, we think its recovery behaviour is significantly better than other wings in the category. But certification tests do not test for real stability, nor do they test for recovery from a real-life collapse. They can only test for behaviour resulting from artificially induced collapses.
During certification tests, pulling the A-risers is an artificial way of simulating real life collapses. The EN certification process requires collapses of defined proportions and specific fold angles, so comparative tests can be made. Due to the A tab positioning, in order to induce a full speed collapse that conforms to the EN certification requirements, the D2 required the use of additional folding lines just for full speed asymmetric test. The folding lines were only necessary for the final few centimetres of speed bar travel. Without the folding lines, an artificial A-riser collapse will pre-accelerate* the wing before the collapse occurs.
The Delta2 was easily certified EN C with the use of additional folding lines for the accelerated side collapse only. But now the rules have changed: even though the D2’s behaviour is well within the EN C category, if it were certified today it would “automatically” receive an EN D rating. Even if it exhibited A behaviour, the overall rating would be D. This D rating is irrespective of the actual behaviour of the wing, unrelated to what pilot the wing is suitable for, and determined solely because of the use of folding lines. We believe this folding line “ban” in the EN A, B, and C classes is the result of political lobbying motivated by a small group of people who are attempting to manipulate the rules for personal gain or out of ignorance/lack of experience.
The easy way to make a wing good for certification is to make a weak profile that collapses easily with A-riser input. This is fine above a lake in smooth air, but in real life the wing will be more prone to collapse – especially on speed bar. We at OZONE refuse to design paragliders with weak profiles to satisfy arbitrary certification requirements that are unrealistic and manipulated by political lobbying. Our philosophy is and always will be to make stronger wings for pilots who fly in real conditions. It is our True Performancecommitment.
As we develop the Delta 3, this commitment remains strong. The Delta 3 has the same aspect ratio and comfort that has made the D2 so legendary, with increased glide and speed performance thanks to profile refinements and focused drag reductions. The eventual overall EN rating will be determined solely by politics, but the passive safety and character of the wing will be squarely in the EN C class, and represents what we think is the ultimate Sport Performance Class wing.
*Pre-acceleration is when the glider accelerates before collapsing. Imagine flying at full speed and pulling an A riser to induce an asymmetric collapse (remember using the A riser is already an artificial way of simulating real life collapses). With the A’s further back in the chord, instead of deforming and folding immediately, the side that you pull actually accelerates first (because of the reduction of AoA), thus momentarily causing a turn in the opposite direction. This makes an artificial process even less realistic, by causing additional acceleration coupled with a roll/yaw action in an opposing direction. These collapses are impossible to experience in real life, yield a potentially a greater fold angle, more chance of shock re-inflations, and sometimes more dynamic reactions.