a barrier. Foils – characteristics and history of airfoil – sailing

  • 1 What is the principle of foil?

  • The chip is an asymmetric wing shape: its asymmetry and curvature mean that when it’s in a state of flux, it generates force. Like the wing of the plane lifts the plane, the chip lifts the boat, there’s just the liquid that changes, we go from air to water. The aerodynamic or hydrodynamic principle is exactly the same. The term foil is derived from foil, which is a shrinkage of the hydrofoil (the bearing plane covered and submerged).

    A foil-equipped boat, also called a foil, can be defined as a sailboat that uses the dynamic lift, relative to speed, of one or more submerged carrier aircraft, to replace Archimedean lift of the hull or hulls.

    This submerged bearing surface can be horizontal or inclined with respect to the hull. The movement of water around this profile creates a force similar to the lift created by an airplane wing. Apparently, foil works in the water like an airplane wing in the air. Of course, an elevator cannot be created without some speed.

  • 2 How does the tin work on the boat?

  • To get ahead quickly, you need to have the least surface area possible for the boat in the water. The water slows down. This is called towing the boat. Using tilted flakes, this generates an upward thrust and loosens the buoy which will then exit the water. By managing to completely remove the structure(s) from the water, virtually all friction and therefore drag are eliminated. The stronger the wind, the greater the load of the chips, the greater the weight of the boat, the gain its speed and leverage. The Ultimes, despite their weight (it’s hard to get exact numbers for weights but about 15 tons), needs at least 15 knots of wind to take off and fly at nearly any speed. For Imoca, it’s mainly called lateral gait like reach (between 80° and 120°) or the direction of the wind that facilitates flight.

  • 3 Who started laying chips?

  • The Flash Butterfly, a small, lightweight boat, changed the game in the early 2000s. Born in 1929 in the United States, it was, in fact, the first device To allow “everyone” to fly on the water at an affordable price.

    A few years later, chips appear onThe America’s Cup, which transitioned into the world of flying boats in 2013, is an AC72 catamaran equipped with rigid wings.

    As of 2020, the chip is ubiquitous in many mediums such as kiteboarding and windsurfing: at the 2024 Olympics, kitefoil and iQFoil will be present.

    In marine races too, chips make an appearance, notably at Imoca for the first time during the 2016-2017 Vendée Globe won by Armel Le Cléac’h, who was 60ft equipped with a small chip.

    The Ultimes, 32 m long and 23 m wide, almost all fly thanks to the foil profiles, bearing surfaces on the rudders and the center plate in the form of a radial wing.

    On the design side, they are also foil: this is the case with the Figaro Bénéteau 3. There are quite a few of them on the Mini 650 circuit. On the other hand, for cost reasons, certain classes such as Class40 prohibit the use of chips.

    So-called recreational sports such as Windfoil, SUPfoil, and Wingfoil have had great success since the advent of carrier aircraft. Even if the prices are still high, some have developed electric skateboards (6799 euros).

  • 4 How much does a chip cost?

  • For Imoca worth 7 million euros, a pair of installed chips with the necessary wells and reinforcements, this represents approximately 800,000. A pair of chips costs 400,000 to 500,000 euros.

  • 5 Is the chip the primary weapon to win?

  • According to the architects, it is difficult to go back: chips increase performance by 15%. I am absolutely convinced that there will be no turning back. When little Mike Birch beat big unicycle Michel Malinowski on the first Route du Rome in 1978, it was said there would be no more uniballs to win the race, in the very short term, in the same way, there would be no more unicorns to win the race, said Vincent Laureau-Prevost, of VPLP Architecture: “A boat without a chip to win the race.”

  • 6 advantages and disadvantages of chips

  • The main advantage is a performance increase of about 15% depending on the boat and speed. As for the disadvantages, they are, first of all, the increased risk of collision with unidentified floating targets. The chips, which protrude 3 meters on the sides of the boat, ignite everything found in the oceans such as logs, containers and other marine mammals. And inevitably, chips become weak when they touch something. Another drawback is the complexity and cost of the systems (read above). Today, architects know it’s better to have bigger and heavier chips, even if that means more weight, because they work at lower speeds, at longer intervals.

  • 7 Who invented foil?

  • It is always difficult to attribute the paternity of invention. In the book “Flying Boat” (1) we can read that the first attempts to attempt to fly a machine over water date back to … 1861, the year in which the Englishman Thomas W. Moy imagined installing three streamlined fenders under a horse-drawn boat along the Surrey Canal, South London. Five years later, Frenchman Emmanuel Farcote, a mechanical engineer, filed a patent for a boat equipped with side stands. Especially in 1905, the Italian Enrico Forlanini, a specialist in airships, took a big step with the invention of the hydrofoil. He tested his mechanism the following year on Lake Maggiore and thanks to a 75 hp engine, he reached a speed of 38 knots (70 km/h) in flight.

    In the years from 1965 to 1980, there were attempts again to fly on different machines: in 1966, Claude Tesseran, one of the French pioneers in the manufacture of hydrofoil sailboats, tested the Véliplane, a plywood 4.50 m long and 4 m wide It weighs 125 kg. Take off the micro-hull multiplayer with Force 3 and hit 15 knots.

    Eric Tabarli on a complete journey. (Dr)

    In the summer of 1976, a frustrating hurricane rolled past La Rochelle with Eric Tabarley at the helm. The most famous French sailors did not stop there and launched, in 1979, the construction of Paul Ricard, the first trimaran with foil. To design this new type of boat, Tabarli called on an aeronautical engineer, Alain de Berg, who was accustomed to working on structural calculations for aircraft such as the Mirage and Rafale.

    The front page of the yachting notebooks about Eric Tarparley's first flight.
    The front page of the yachting notebooks about Eric Tarparley’s first flight. (Dr)

    Alas, very quickly, all these little people quickly realized that the materials at that time did not allow them to design a boat light enough to take off. Despite its 17-ton weight, this 16.50-ton model won an Atlantic record (10 days 05 hours 14’20”) in 1980.

    The launch of l'Hydroptère.
    The launch of l’Hydroptère. (Dr)

    Paul Ricard has never flown by plane, but l’Hydroptère will succeed: the idea still comes from Eric Tabarly, but one of his young majors, Alain Thibault, who in 1984 took charge of the project. Ten years later, l’Hydroptère has reached 35 knots. In front of Port Hyeres, in 2009, this three-wheeled vehicle set a speed record over 500 meters at 51.36 knots.

    For the general public, a few projects saw the light of day in the 1990s: this is the case of the Trifoiler, built by Hobie Cat in the United States. Designed by naval engineer Greg Ketterman, this trimaran is 6.71 meters long. Production began in 1994 and ended in 1999. This machine has allowed many avid hobbyists to discover the pleasures of high-speed flying.

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