Technology

How the Saildrone Wing Was Born

The saildrone's patented wing design enables the USV to cross oceans while only consuming a few watts of electricity—but the wing was originally born on land.

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Saildrone
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January 5, 2016

Sailing enthusiasts might assume that Saildrone’s wing design was inspired by America’s Cup winged trimarans and catamarans, but the design actually comes from a decade-long pursuit of a world land speed record.

British engineer (and Saildrone CEO) Richard Jenkins was an undergraduate in mechanical engineering at Imperial College London in 1998 when he was first introduced to land-sailing and the idea was to beat the wind-powered world speed record, which stood at 116.7 mph at the time.

That kernel of an idea became a passion pursuit he called Windjet. For the next 10 years, 1999 – 2009, Jenkins relentlessly pursued the record, testing five different evolutions of the vehicle, on a mixture of surfaces from ice in Canada, to Salt lakes in Australia, to dry, alkali lake beds in North America. In 2007 he finally found a title sponsor and partnered with Ecotricity, a UK wind power producer,  and the Windjet Project became known as the Ecotricity Greenbirda nod to Donald Campbell’s Bluebird, but run on clean wind power, rather than dirty fossil fuels.

Like Bob Schumacher, who set the 116 mph record that Jenkins aimed to beat, Jenkins designed his land sailing vessel with a rigid wing, rather than a conventional sail. For strength and stability and to minimize weight, Jenkins’ vehicle is built almost exclusively of carbon fiber; bearings for the wing and wheels were the only metal parts on the Greenbird. The wing produces thrust similarly to how an airplane wing generates lift. Wind passing around the wing propels the vehicle forward at up to five times the wind speed.

The real innovation, the one that allowed Greenbird to break the speed record, was the aerodynamic wing control.

On a sailboat, the sails are trimmed with ropes and human force, which requires a lot of power and precise control. Jenkins’ innovation was to use aerodynamic control, so the wing would trim itself for optimum power. In the same way that the tail on an aircraft controls its pitch, and hence the lift generated, the Greenbird tail, mounted vertically, would very precisely control the “angle of attack” of the wing, thus producing maximum power, without stalling. A small tab on the tail—usually referred to as the “elevator” on an aircraft—controlled the tail, while consuming very little energy.

On March 26, 2009, on a dry lake bed in California’s Mojave Desert, Jenkins used the tail innovation on Greenbird to break the existing record by nearly 10%, clocking a new world record speed of 126.2 mph.

After breaking the record, Jenkins moved to California and turned his energy toward sailing on water, but using the unique Greenbird wing/tail/tab system. This led to an unmanned, autonomous surface vehicle, which became Saildrone.

Learn more about the technology that powers Saildrone.