Flywheels are typically made of steel and rotate on conventional bearings; these are generally limited to a revolution rate of a few thousand RPM. Some modern flywheels are made of carbon fiber materials and employ magnetic bearings, enabling them to revolve at speeds up to 60,000 RPM (1 kHz). Carbon-composite flywheel batteries have recently been manufactured and are proving to be viable in real-world tests on mainstream cars.
1925: The Tri-State Tornado. Indiana was one of three Midwest states in the path of the deadliest tornado in American history. On March 18, 1925, the Tri-State Tornado traveled a record 219 miles on the ground from Missouri through Illinois and into Indiana, where it struck Posey, Gibson and Pike counties.
(CNN) -- Here are the 10 deadliest tornadoes to touch down in the United States, according to the National Oceanic and Atmospheric Administration: 1. The Tri-State Tornado killed 695 people and injured 2,027, traveling more than 300 miles through Missouri, Illinois and Indiana on March 18, 1925.CNN) -- Here are the 10 deadliest tornadoes to touch down in the United States, according to the National Oceanic and Atmospheric Administration: 1. The Tri-State Tornado killed 695 people and injured 2,027, traveling more than 300 miles through Missouri, Illinois and Indiana on March 18, 1925.