GIN Boomerang 12 (Competition CCC)

Designer Gin Seok Song explains the development process of the Boomerang 12:

“GIN Lab was created to find the next breakthrough technology in paragliding. We recognised that we were approaching the limits of possibility just by changing things like aspect ratio or cell number, so we were motivated to seek out a big physical change. After consulting with Professor Jooha Kim at Ulsan National Institute of Science and Technology, we became intrigued by the research of Professor Kim on the leading edge tubercles on the humpback whale flipper.

We then decided that the best approach would be to build a real simulation in a wind tunnel. Wind tunnel research is difficult and expensive, but there is only so far you can go with pure software simulation. Fortunately, we were able to secure research funding and the “GIN Lab” was born in 2019 as a collaboration between Gin Gliders and Ulsan National Institute of Science and Technology.

Professor Jooha Kim: Over many millions of years, living creatures have evolved highly effective mechanisms to cope with the challenges of their environments. One example is the tubercles on the pectoral flipper of the humpback whale. These have been shown to enhance performance and lifting force at high angles of attack. This gives the whale incredible agility in spite of its huge size. After Gin explained some of the challenges of paraglider performance, I became very interested to investigate how this concept might be applied to paragliders. Tubercle airfoils always stall gradually and can be operated at higher pitch angles which produces increased lift. The drag penalty is significantly reduced and tip stalling can be attenuated and even eliminated completely. That combination of performance characteristics means that tubercle airfoils are hyper-stable and very efficient.

We decided that the wind tunnel would be a valuable tool, enabling hundreds of experiments and rapid iterations on small modifications.

Gin Seok Song: the first challenge was to calibrate the basic wind tunnel results to our computer simulations and practical experience of the real wing behaviour. Once we had a good model, we were able to try various configurations on the leading edge. We then took the most promising results and built real paragliders. It was immediately apparent that the concept had potential, especially in relation to stability of the wing and sink rate in the climb.

1.5 years later, the project had progressed to the stage of being able to certify the Boomerang 12 with the new leading edge technology: we decided to call it the “Wave leading edge” as its inspired by marine life and has a sinusoidal appearance. What was surprising was the ease of certification: following a collapse the shooting is much reduced and the wing tips don’t snake like the previous generation of 2 liners. The wing was first flown by our factory pilots at the 2021 PWC Superfinal in Disentis, Switzerland with encouraging results and podium finishes in both the individual and team rankings, followed by an overall victory at PWC Turkey and in 2022, a 1,2,3 at PWC Brazil.

We are really excited about the future of the Wave Leading Edge, the stability and high angle of attack performance is something that should benefit most categories of wing."

MATERIALS

Canopy cloth

Upper surface leading edge: Dominico 30D MF (WR) 41g/m²

Upper surface: Porcher Sport Skytex 32g/m² / 27g/m²

Lower surface: Porcher Sport Skytex 27g/m²

Lines

Upper: Edelrid 8001 090 | 070 | 050 | 025

Middle: Edelrid 8001 130 | 090 | 070 | 050 | 025

Main: Edelrid 8001 360 | 190 | 090 | 070