Tech talks from Chubanga design team - F4E

CHUBANGA V3 Design Team

For the Chubanga V3, a proper design team under the guidance of Luca Filippi was formed.

The initial design team was all Italian: Giorgio Provinciali, Simone Bartesaghi (F4E collaborator) and Franco Lovato. A later addition coming from France was the right move to finalize the design: Charles Dhainaut joined the team working closely with F4E. The final design was then performed by F4E collaborators (Simone and Charles).

The design team started from Chubanga V2 experience; by using custom F4E proprietary tools developed to estimate hydrofoils performances, the design team started the new project with given targets from Luca and his top riders’ feedbacks.

Can you tell us what is F4E ?

F4E - literally Fluid4Engineering - is a company started after the 35th America’s Cup experience. Professionals involved in the F4E project have a curriculum enriched by participating in Volvo Ocean Race and America’s Cup campaigns. In a way, F4E provides methods and tools useful to estimate fluid dynamics properties, mainly for sailing yacht and mega yachts; in this case F4E was in charge of the optimization and performance estimation methods.

What is your biggest achievement with F4E and personally ?

Of course the last one is to see the Chubanga V3 in water with Mario (Calbucci) hitting top speeds higher than 40 knots… Another bigger achievement of F4E was the optimization of a sailing yacht hull, the Grand Soleil 48 Race. A citation in Seahorse magazine was the pinnacle of this project. Another important project was the design of a SUP for the brand “Superfluid” created by a famous design studio, BorromeoDeSilva, in Milan. Here again, top magazine interviews with citations enriched the project. 

Simone, now consultant of F4E, did the 2011-2012 Volvo Ocean Race campaign as CFD engineer for the team CAMPER with Emirates Team New Zealand and the 35th America’s Cup, again as CFD engineer, with Artemis Racing. 

Charles, as a professional helping F4E, worked on the past projects for Phantom Windsurfing, TF35 catamaran, ENATA Marine.

Since when do you know Luca and work with him ?

We know Luca Filippin since 2018, just after the last AC cycle. We were designing the Superfluid SUP and thanks to Giorgio (Provinciali) we get his contact to talk about carbon fibers, moulds and construction of that… at the end of the day, after a couple of beers, we agreed on the idea of starting to develop the V3...

How do you work on the design of the v3 ? Do you start from blank project or try to improve the v2 ?

For the V3 we started from the V2 experience regarding the foil sections. We did a deep study of them and different cycle of optimization to achieve the required targets. For the main and stabilizer wings, we tried to maintain the V2 distribution but at the same time implementing Luca’s ideas, working on the tuning of general shapes to achieve the desired lift, no tip ventilation and good stability. 

How was the development process  ? What are the main change on V3 from the designer point of view and what features would you point to ?

The development process was similar to any high performance racing project except the structural part. Here we did only the hydrodynamics study. Usual process is to start from a piece of blank paper with defined targets (global geometry dimensions and performances). Second step is the 2D foil section analysis and 3D planform initial design to have the “Point 0” to use as a reference. Different optimization loops are done to achieve the targets and the final tuning is alway done manually by looking at the results and of course by using our knowledge.

The main change of the V3 was the main wing planform design, which brought a different configuration to try to achieve speed and acceleration.

What is the most important thing to consider to design a foil ?

The most important thing to consider is the idea to have a tolerant glider… capable to have good performances upwind and downwind, less sensible to stall or cavitation. 

Now some question from the rider point of view, we always try to avoid ventilation, how you deal with that on the design ?

As we told you before, the main wing was designed to have a proper lift distribution that helps to avoid ventilation when tips are piercing the free surface.

In which "weather condition" the chubanga v3 is studied or gonna works better ? Lightwind, strong wind, flat water or deep sea or all around ?

Chubanga V3 design is thought to work all around in upwind and downwind conditions and achieve good VMG, i.e good angles because it is not only related to the top speed. Of course, the ideal condition is with flat clean water but this is valid of course for all the other competitors.

Is that possible for non racer to use the chubanga v3 ?

We think Chubanga V3 is not a entry level glider because it is designed for top class riders but after the testing riders feedbacks, we think that this glider could be also used by riders with a bit of foiling experience and not only reserved for top athletes. 

Can you tell us more about your project for 2020 and in the future ? How do you see the future of kite foiling ?

The future of kite foiling is for sure a Chubanga V4...because the best one is yet to come!

*Itw realized by Seb Queney for Chubanga

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