Tribord Amure par Matthieu

As promised, here is an interview of Dimitri Despierres, one of the many French who participated in the design of the wing sail of BMW Oracle Racing. Another interview was published on Voiles et Voiliers web site yesterday (in french), I invite you again to read for those questions and answers are complementary, finally mine is much better …. For more details on Dim, you can also read his interview (in french) Advice expert of 2007 on this blog. Thank you Dim.

Ce billet existe aussi en français: Avis d’expert: Dimitri Despierres, concepteur de l’aile de BMW Oracle Racing

Tim Smyth (Core Builders) et les deux Français Dimitri Despierres et Steven Robert (HDS)

Can you explain the plan of this very special project: How many times for developpement, construction?. How many people ? your role?.
The studies were made between mid-December and late April or early May, even then an impressive number of studies have continued in CFD to confirm and better understand the use of the wing. Mainly Joseph Ozanne (FRA) for the study in close collaboration with Francis Hueber (FRA) and Mario Caponnetto for CFD.

Couple experts and consultants we help us in making choices for the wing. Share their experience on the wing of S & S 88. These two guys were missed.

Construction begins mid-May for some elements. The group structure was composed of 6 persons including 3 on site really has always Anacortes. That’s what has made possible the realization of this project in as little time with immediate answers to questions of the construction team. The construction is made of 4 different sites including 2 sites in close proximity to one another in Anacortes. 50 people in Anacortes (West Coast) and 15 people on the East Coast have been working hard to give life GARLIC. All this beautiful world is found in San Diego for final assembly.

The job type were more diverse than ever, between the structural engineer, mechanical, aerodynamics, electronics, hydraulics, boat-builders (or should I say Wing-builders!), The riggeurs, specialists for the aeronautical film quality machinists, mold makers for Boeing and so on of the best …

My role in all this was to coordinate and develop some mechanical and composite wing. I mainly provides the link between the group design and construction. I made sure to keep the original guideline, all that remains simple and easier for builders !

What is the principle of the wing sail and the difference with classic sail?.

The wing principle are the abilities to create a lift coefficient greater than conventional sails, with control over each flap and therefore mastery of form that is sought. It is much easier to obtain the desired shape on computers via a rigid wing sail through classic. Among other things, the rigid wing comes to creating a lift equal to one mainsail and headsail from about 7 knots. I leave you to imagine the ease of use of such a wing and far less effort compared to conventional sails. Just the load mainsail (for a classic sail) to get the same twisting theoretical is would be jalous a structural engineer!

Can you describe the architecture of the wing-level structure? Differences with Stars & Stripes in 1988 outside the size and the Class C and A which is already used.

The wing consists of a « main element » and its flaps (8 flaps). The « main element » is the structural part of the wing like tradionnal mast. The « main element » is composed of 3 parts: The fore cone (part kevlar yellow visible on the front of the wing). This is a non-structural. It is for give the airfoil shape defined by Joseph Ozanne.
The black (carbon) behind the cone is the « main element main spar » roughly the mast, the true element that supports compression of the wing and keeps everything else in bending and torsion. It is a true tunnel in which not one but several people can enter and move in! It’s a real lift, especially since there even need to turn the crank to send guys up. After this element there are the horizontal panels. Some of the panels are called « key panels » because they take up more vertical effort. Some others are called « intermediaries (medium) panels » who are there almost only for enforcing the aerodynamic shape of the wing once the film taut and affixed by a thermal process (technique used to make the tail of glider and some aircraft).

After this « main element » are the 8 plaps. They are designed virtually on the same principle except that both, the « cone » and « spar » components, are the only one…. but these panels have a frightening lightweight both, the front part and flaps. They are all composed panel honeycomb and two carbon skins. All these panels are perforated… As I said before, that’s a shame we will not be able to see this frame. It’s beautiful. A look at a smaller scale of what we have done is simply extrapolated from what we see on C-class.

Differences with respect to S&S 88? I would say it’s the same concept but with new materials, with most optimized methods… David Hubbard, who incidentally is return to work with us.

What are the settings of the wing? What we can control? and how?; Is it controlled by computer, is that the engine is essential.
The settings of the wing is firstly … the camber. Then you rotate the whole vis-à-vis the platform. It’s the traveler (or the equivalent of a trolley mainsail, if you prefer). This setting turns all the wing on its pivot point located under the « main element ». It’s the foot mast… Here, there is no longer mainsail sheet! This setting is replaced by an actuator that controls the twisting of all flaps. Add a few subtleties which allow setting the twist of each flap against each other and you get the effect of mainsail sheet without tension transmitted to the platform!

All these commands except the (mainsail trolley?) is controlled by hydraulics. The (trolley?) returns to a winch operated by hydraulic pumps through the engine. But the engine is not essential. To control the wing via a traditional deck layout (columns with winchs and hydraulic pumps operated by human power) is completely possible and even much easier than managing conventional sails! The trim can be done manually via the trimmer or via a PLC (Programmable Logic Controller). I leave you explain that. Once you have returned to target values of twisting from your academic studies based on a strength and a wind angle or coefficient of lift you’re looking for, you can imagine that all that is self- ruling.. It’s like an airplane on auto-pilot!. Add a cylinder on the traveller and it will not be far from an America’s Cup solo! Soon a man aboard to steer (and again …) and 60 guys to handle the boat ashore … What’s wrong!

It seems that the trimaran accelerates much faster in the gybes and tacks. Is what we can imagine with these new capabilities to make the multihull match race?

The wing has definitely opened doors. And maneuver capabilities are increased for the match race… we are being watched closely by Alinghi and they already know from the radar track record that they can not compete with us in this area, unless they have a wing. The wing begins to produce lift almost immediately at small angle with minimum drag (I not revealed anything) … I imagine that with your knowledge of sailing in catamaran sport you quickly understand the reciprocal this kind of application!

Do you think there are other major innovations to come? True foil? Kites?
Yes if the 33 AC is in August 2012. We are still full in cartons! And honestly I hope nobody wishes to that! …The America’s Cup is certainly the Deed of Gift, but also the consent and a level of regulation that may give rise to the equally exciting research while having a 15 teams ready for battle on the water.

As Alinghi, you removed the winchers, and now the trimmer, which is the next victim? Is it the tacticians on board?

The helmsman …! (Sorry Jimmy!). Just kidding, whatever … And everything is now possible with the technology we have (by open rules I mean). Recognition of the opponent’s movements, tactical and strategic investments ideals, you can remove the tactician. the helmsman side, you can put your GPS mark, if you would imagine a bit, the wing can fly « alone » and the same principle can be extended to the rudder system with a good controller depending on the trim of the boat all this related to the ultimate goal of performance. You know as well as I learn the software much faster than what humans are critical parameters to a target. You must remember that in 2003 a company we had already discussed for us to offer this type of software for performance analysis. Then the teams would all have more or less equipped. Link this type of analyzer to a controller; it can make the cup in the chairs of Vel et Vent in Valencia (how horrible!).

It will not happen, we’ll stop just before the ridiculous does not kill!

Do you have imagined wing in Valencia in February. In darsena

Yes, why not? Everyone seemed petrified at the thought of this wing in Valencia in the Darsena. It will be spectacular, especially people who do have not seen will actually achieve its size. Airbus has recalled all its A380, they refuse to fly with wings smaller than ours . More seriously, it will be great to offer the view of many the culmination of 2 ½ years working with 2 teams that are rotten life and that of many outside throughout this time!

Finally See you in Valencia?
If I come! Well yes okay, I’ll make the tour of Dogzilla.