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150 00 Praha 5 - Motol
Czech Republic
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Everlast VO system Falcon Wingtip Colors
BiGolden4

  For our development team, to design a new tandem glider is not only a great pleasure but also a great challenge, especially after the successful BiGolden3 model. After four years on the market, BiGolden3 is still the most successful tandem glider and also to be true inspiration for other designers.
 Generally, to design a new tandem wing means to utilise as many of the latest innovations and technical solutions as possible to create a single compact design which exceeds expectations. In the case of the BiGolden4, we have been working for eight months on development and flown lot of hours in all possible conditions using six different prototypes. The development of the new wing was quite straight forward and very effective, so now we can proudly introduce the successor of the legendary BiGolden3 – the new BiGolden4.

BiGolden4 – technical specifications

Let's go one by one through the technical specifications.

Canopy

- The brand new flat and frontal canopy shape delivers high glider stability at all flight regimes.

- Newly developed aerofoils deliver high performance, lower pressure in brake lines along with a high degree of canopy stability.

- The brand new and completely redesigned inner layout of diagonal ribs and reinforcements lowers the total usage of lines while maintaining the compactness of the wing.

- There is new reinforcement of the leading edge with special nylon rods which makes canopy lighter (in comparison with BiGolden3) and makes shape of leading edge smoother. This new reinforcement of leading edge makes the start enjoyable.

- Arch reinforcement with nylon rods around the attachment points perfectly distribute stress from the lines to the ribs, diagonals and in to sails for various weight loading of the wing. Thanks to that is shape of canopy much smoother.

- VO system of the cell openings for easy take-off characteristic even with nil wind, perfect "> pressurization of canopy distribution in all flight regimes and controllable reinflation after collapses

- The Falcon Wingtip is innovative backward-shaping of the ears which lowers induced drag and thus total aerodynamic drag of the wing

- Miniribs on the trailing edge create a cleaner aerodynamic shape

- Skytex Everlast. The double coating of the fabric significantly improves durability of the wing (especially on the leading edge) and thus prolongs the life span of the wing with no extra costs.

Suspension

- We use the best possible lines from reputable manufacturers: Liros (type PPSL and DC) and Edelrid (type Magix Pro).

- New suspension layout. We use shorter lines in the upper cascade which saves 10 % of the total lines usage (compared to the BiGolden3) and thus lowers the total aerodynamic drag. The new layout also better absorbs air turbulence so the flight feels more calm for both pilot and passenger.

- New layout of outer A-lines suspension folds more of the leading edge when doing big-ears, causing the wing to sink faster.

- The main lines are completely made from covered Dyneema material (type PPSL manufactured by Liros). These lines are excellent quality with great loadbearing capability and long lifespan. They are lighter than the Aramid lines which were used for the BiGolden3.

- The rows of main lines are distinguished by colours which makes manipulation on take-off easy.

- The lines in the middle and upper cascade are uncovered which decreases their diameters and thus reduces the aerodynamic drag. We used the combination of materials Dyneema (Liros DC) and Aramid (Edelrid Magix Pro).

- The diameters of the lines are getting progressively smaller towards the wingtips and the trailing edge to lower total aerodynamic drag and weight.

- There are loops in the C-line and D-line rows allowing easier adjustment when your glider is serviced

Risers

- The new system of risers and redone trim system allow a higher maximum speed

- Divided A-risers for fast and easy execution of big-ears.

- Big-ears Cleat System the new neoprene-covered cleats makes it possible to secure the outer A-lines in place. This system allows the pilot to fly with big-ears without holding the lines themselves so that the brake handles can be controlled at the same time. Also, the neoprene cover of the cleat prevents unwanted catch of any other line. The outside A-line is divided in two pieces due to fast and easy repair if the cover of line is damaged.

Conclusion:

We have increased performance, stability, maximal speed and, of course, passive safety, all while reducing the overall weight of the wing. BiGolden4 is the lightest tandem glider ever produced by Gradient. It is crucial for our development team to maintain favorable and well-balanced flight characteristics achieved with the BiGolden3.

All that so that everyone, pilots and passengers alike, can proudly say: “This is the best tandem wing I have ever flown”.