The decision by the Paraglider Manufacturers Association to regard about 70cm long, 1.5 mm diameter carbon rods, which are tensioned like a bow and sewn to the profiles of a paraglider as “rigid primary structure” rather than as “flexible and secondary” was not taken easy. It was preceded by very intensive discussions, which took several weeks:
On one side there isyellow, on the other side is red, in between we have orange. The question which we had to answer was: How much orange is still yellow and when does it start to become red?
There are two possible extremes of a wing with a pilot who is suspended below this wing by lines: A very simple paraglider just consisting in cloth and lines without any Mylar or other reinforcements and an Atos-type wing under which the pilot is suspended in a paragliding harness by 2 lines, holding 2 or 3 other lines in his hands to control the wing. Somewhere in between these two extremes we had to draw a line, which defines where a flexible paraglider ends and where another type of aircraft starts.
The PMA sees the Ozone BBHPP as the first “tentative step over this line". Soon it will be followed by machines which will be maxing out the principle of the rigid primary structure. These wings will differ much more from the principle of the traditional, flexible soft-paraglider than the Ozone proto is doing it today.
The decision by FAI to limit the FAI-Class-3 22 years ago, when the FAI definition was introduced, is still a valid decision today. It helps to preserve the simplicity of the simplest flying machine existing. Most of the success of the paraglider comes from the fact that it is simple and easily accessible.
If a new FAI-Class for paragliders with rigid primary structure will be introduced, depends on you, the pilot who wants to fly it and on designers and manufacturers who want to design and produce it. It will not be dictated by FAI or PMA or anybody else. It will be decided by the market. What had to be decided is a definition for “rigid primary structure” because as the long discussions in the PMA working group showed the FAI definition for FAI-Class-3 is too vague to be understood in the same way by everybody.
The proposal for a revised definition of FAI-Class-3 was voted upon by all PMA members. The polling was heavy, 78% of our members voted. The vast majority, 76% of the voters, choose the following definition:
Hang gliders having a flexible structure (paragliders), and which are able to demonstrate consistent ability to safely take-off and land in nil-wind conditions.
Flexibility is defined by the ability of a component to be bent around a radius of 1cm by 180° without being damaged. This test of flexibility will be executed in at least two perpendicular planes and will be performed when the component is integrated into the glider.
Note: all rigifoilmaterials and all Mylar reinforcements as used up until today in certified gliders will fit inside this definition.
Pilots, designers and manufacturers will choose to decide to introduce or not to introduce a new class of paraglider, which will give room for more rigid structures. This will not only give the “new developments” room, but also protect the proven and very successful principle of the classic paraglider.
Until now nobody knows ifthe repeated attempt to equip a paraglider with rigid structures will be successful this time. Look at the several attempts in the history of our sport: from the rod-wings of André Bucher and Karl Bauer to the revolutionary mono-sail up to the last designs of Laurent de Kalbermatten, the Pantair etc.
In contrast to the principle of the classic paraglider, where all components are only loaded by tension, these rigid materials are able to receive compression loads. This is not only opening the doors to new possibilities, it is also causing some new risks. At least now something can crack as well, not only rip. Obviously this changed demand on the materials is causing the need of a different treatment of the machines (also in the certification process).
If there would not be a differentiation in between these basic principles of construction in competitions, everybody would be forced to follow the new trend to be competitive in performance. But some designers don't want to do this, because they like the brilliantly simple, straight forward principle of a classic paraglider which has proven to be suitable for the masses and which has been successful because of that. By limiting the classic paraglider design as it has been done until now in FAI-Class-3, this principle has still a chance to survive, also in competitions.
Finally this discussion regarding the "rigid primary structure" and a new, better defined and clear FAI definition of a paraglider is only a side issue. The competition sport is moving more and more away from the focus of attention of the normal pilot. This tendency is already developing since many years now.
In the beginning, when the competition sport was still interesting for every pilot, all competitors were flying with the same, serial and certified wings as every other normal pilot as well (AilesdeK Big-X).
Then we flew the serial canopies with just thin lines (Edel Racer, UP Katana, Nova Sphinx etc).
After all there arrived the first machines of the new Open Class (Xenon, Boomerang). These machines were still produced in big series and were available for everyone to buy and flyable by many.
The latest development is to build very complex prototypes which are individual constructions and which are not sold anymore, because a normal leisure competition pilot is not able to handle them. Therefore more and more "normal pilots" will lose their motivation to compete in an environment which does not offer fair and equal chances for all pilots. And also more and more manufacturers will give up their open class engagement because of the huge effort and costs involved (at the moment only about 1/3 of the more than 40 manufacturers who sell internationally are active in competition with open class wings).
Actually the PMA working group "competition gliders" is discussing solutions to this crucial question. We hope, that we can offer some good proposals to CIVL soon.
A short excursion to what would happen if paragliders with “rigid primary structure” would be developed to be certified and sold as Serial Gliders:
The testing laboratories agree on the fact, that paragliders with rigid primary structure cannot be tested following the existing EN-926.The FAI definition of a paraglider also is the definition of a paraglider in EN-926.EN-926-1 does not contain any tests for components in paragliders which are exposed to compression loads and which can not only rip but also break.To make a front collapse of 30-40% as described in EN-926-2 already is difficult with some of the 3-line wings. It’s impossible to do on a 2-line wing, where perhaps 80-90% of the load is on the front row of lines. The quality of an asymmetric collapse which is caused by pulling one front riser is completely different to the one of an asymmetric collapse on a glider where a major part of the load is carried on the 2 or 3 remaining rows of lines.New testing criteria for paragliders with components, which are exposed to compression loads and/or with only 2 rows of lines would have to be created.The refined, precise definition of FAI-Class-3 (paraglider) is important for all pilots, designers and manufacturers, competition organizers and juries in competitions and last but not least also for the testing laboratories to know what is a FAI-Class-3 paraglider and where exactly are it’s limits.