British engineer Richard Jenkins and his team, sponsored by the largest UK renewable energy supplier Ecotricity, just set a new world land speed record for wind powered land vehicles of 126.1mph (202.9km/h) at Ivanpah Lake, Nevada.
The Greenbird is a high tech combination of racing yacht, aeroplane and Formula 1 racing car design and technology. Lightweight, low friction and minimized aerodynamic drag are the secret ingredients behind the world record. The entire structure is made from carbon-fiber which has the high stiffness and strength required to transfer the wind loads on the Greenbird vertical sail, into traction forces on the ground. The suspension allows some compliance between the vehicle and the rough dry-lake surface; otherwise it would be difficult to control.
Greenbird weighs around 600kgs (1320lbs) but the ground pressure is around 1ton (2200lbs) at high speed. The forward thrust comes from the wind flow over the aerofoil section, just like an aircraft wing that creates lift, so the pressure differential over the wing creates forces that get translated into forward velocity. The Greenbird has such low drag and low rolling friction, that it uses the wind energy very efficiently, and can actually travel at speeds 3 to 5 times faster than the speed at which the wind is blowing.
The team is going to attempt another land speed record but on ice, but it requires a different structure which has more compliance than carbon-fiber solely so aircraft quality spruce with carbon-fiber surfaces is used. The ice-sailing vehicle has skating blades instead of wheels. The world record attempt will be made at Canyon Ferry Lake, near Helena, Montana in the USA. The 35,000 frozen acres and 76 miles (121.6km) of shoreline make the Canyon Ferry Lake perfect for iceboating with little snow and strong breezes.