Inspired by nature’s genius -
Innovative composites make the impossible happen

With miraculous strength and lightness, today’s composite materials are moving from aerospace and high-tech specialty applications – like fighter jets, Formula One cars and Volvo Ocean Racers – to become part of our daily lives. These incredible materials make so much possible. Now we can finally rival the structural genius of nature – such as the strength of spider’s silk or the lightness of a feather.

Fast enough to win, strong enough to stay together

By any measure, today’s  VO70s are masterpieces of engineering. “The third-generation of these boats are bulletproof,” Andy Lowe, Boat Build Team leader, proudly says about the latest boats being constructed for The Volvo Ocean Race. Lowe is the for the Ericsson Racing Team. His experience includes many years of development and construction of off-shore racers as well as the towering and fragile America’s Cup boats.

So, what are the origins of these extraordinary materials and the engineering advancements they enable? Where did the quest for speed under sail begin, and what part have materials played?

To answer these questions we need to go back in time and look forward, touching upon diverse enterprises such as merchant shipping, early aviation, aerospace and even communications.

But first, let’s talk about materials.

A look at monocoques and composites

Basically, composites are the combination of dissimilar materials that yield new beneficial characteristics – a synergy that results when thread-like strands of material are isolated in a matrix of hardened plastic resin.

The standard we all recognize is spun and woven glass fibers in polyester resin – better known as fiberglass. This mainstream solution is seen everywhere today, from garden pools to kitchen appliances.

But for really high-performance applications, sheets of lighter, stronger fibers are pre-impregnated with epoxy to form carbon, kevlar and PBO. Prepreg, as these materials are called, is kept frozen in rolls prior to being laid into a mold. Compared to the process of using wet resins in conventional fiberglass construction, this approach is both easier and cleaner to work with. A crucial advantage to prepregs is also the ability to build in an exact fiber-to-resin ratio for optimal strength and bonding in the lamination process.

The highly formable nature of composites allows the construction of monocoques – structures that gain their strength from curving, shell-like forms that better distribute loading forces. Examples of man-made monocoques include injection-molded skis, gliders and car bodies. Often these constructions require no separate skeletal frames and ribbing needed for strength and stiffness.  ¬Basically, monocoques mimic successful structures in nature such as egg shells, hollow bird bones and the bodies of insects.

The search for speed under sail

Thousands of years ago, island-hopping Polynesians created light and speedy outrigger canoes. These delicate but seaworthy forerunners to today’s multihulls allowed them to traverse open expanses of the Pacific, often at remarkable speeds. The next breakthrough in speed came in the mid 1800s with the Clipper Era. This is also where we find the first references to composite construction – in this case the clever combination of iron and wood.

During this period, several advanced Clipper ships were created that were ribbed with thin iron frames and then planked with wood. They were fast and successful due to their greater lightness compared to ships with massive wood framing.

Famous examples of composite clippers include Cutty Sark and Taeping. In fact, in 1876, the same year Ericsson started as a telecommunications company, Cutty Sark sailed from Woosung outside Shanghai to London in a record 109 days. Many of the speed records set by these cargo ships stood for more than a century before being finally broken by sophisticated ocean racers in the 1980s. Today, the Ericsson Racing Team could complete this passage in less than half the time, while simultaneously communicating with the outside world via email, voice and video.

While iron-hulled ships and later welded steel hulls quickly came to dominate commercial shipping, builders of racing yachts continued using the composite method of wood planking over metal frames for many years. At the same time, they began to explore alternatives that offered much greater lightness, strength and durability.

Look to the skies

With the triumph of the Wright brothers in 1903, the airplane quickly went from being an experimental concept to a commercial success. New thinking was immediately applied to make fabric-covered planes strong enough to handle increasingly powerful engines and the greater forces from the resulting gains in speed and weight.

One of the most workable alternatives for constructing airplane fuselages came from laminating thin layers of light-density wood with strong glues. Notable successes from the mid 1930s to the early 1950s include the twin-engine De Havilland Mosquito bomber, the eight-engine ‘Spruce Goose’ and even a British jet called the Vampire. Similar wood lamination was also widely employed in boatbuilding. Referred to as cold-molding, it is still in use today.

Plastics made a huge impact on the 20th century and are one of the key ingredients in today’s composites. The first practical synthetic plastic appeared on the industrial landscape in 1907 when Bakelite was introduced by a Belgian immigrant to the United States named Leo Beakeland.

Bakelite was used for making all manner of objects including a variety of communications-related products such as audio records by Edison, telephone receivers by Western Electric, cameras by Kodak and radios from Philips. With Bakelite, plastics became the defining material – artistically, practically and culturally – of the modern era.

Then came the fibers. Early experimentation with threads from molten glass extends back to Egyptian times. However, it wasn’t until the late 1930s that the potential of spun and woven glass fibers saturated with suitable plastic resins began to be more fully explored. The era of fiber-reinforced composites was born.

Sandwiches – Choose your core: balsa, foam or honeycomb

Any discussion of modern composites inevitably involves references to sandwiches and cores. Cores are light, filler materials – foams or honeycombs – that are sandwiched between skins of resinated fabric prior to hardening. In the case of VOC boats, the contenders are using carbon-fiber skins laminated on each side of a nomex honeycomb core.

The idea behind cores is to create a girder-like distribution of force: tension on one side is expressed as compression on the other. The result is an incredibly strong and stiff structure: A composite laminate built as a sandwich-core construction is many times stronger and flex-resistant than a single thick skin of resinated fiber by itself.

Today, we see the most extreme expressions of composite capabilities in new aero-space applications and, once again, the benefits offer many advantages for boatbuilders. “We’re using several new methods, including one from the aircraft industry to help us to build more accurately, as well as to achieve better weight control and resin content,” says Lowe.

Some recent triumphs for these more extreme composites, in the air and beyond, include SpaceShipOne, the first successful private effort to reach space; and Challenger, the first plane to fly non-stop around the world without refueling. Both endeavors would have been impossible without the structural advantages of composites. Just as in boatbuilding, these high-end materials are also quickly going mainstream: The latest generation of business jets are being made in carbon, as are the new flagship commercial airliners from both Boeing and Air Bus.

While the exchange of ideas has primarily been a trickle-down from aerospace to the boatbuilding world, we’re now seeing good thinking and qualitative construction from the boating scene that is attracting attention for airborne applications. “The aero-space people are interested in how we manage to work such big surfaces and still get good results on the finish as well as on the structural properties,” Lowe explains at the same moment his crew – with obvious professional pleasure and a good deal of fun – begins to lay the first layer of carbon prepreg into the mold that forms the foundation of Ericsson 4.