The inflow end of the wind tunnel is connected to a bank of truck-size steel cylinders that hold a total of 20 tons of air at 2,400 pounds per square inch. The exhaust end is connected to a spherical 48-foot-wide steel vacuum tank behind the building. First, the air is pumped out of the sphere, simulating the near vacuum above 80,000 feet. Then, compressed air from the tank farm flows through a hydrogen- and oxygen-fueled heater that raises the temperature to more than 4,000single page
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.