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.
Tornado Information for Donaldson, Indiana. Donaldson, IN is a High Risk area for tornados. According to records, the largest tornado in the Donaldson area was an F4 in 1963 that caused 70 injuries and 1 deaths. *Tornado risk is calculated from the destruction path that has occured within 30 miles of the location.