Effect of Hypersonic Speeds Recently, intense research has gone
into the development of planes that can fly at hypersonic
speeds, approximately five times or more than the speed of
sound. At these speeds the properties of air change radically;
there is a rapid increase in temperature associated with the air
flowing at such speeds along a plane's surface. The U.S. Air
Force is working to develop an aircraft that could travel at
13,000 mph (21,000 kph), a speed that would generate
temperatures greater than 3,500°F (2,000°C). Sections in this
article: The Columbia Electronic Encyclopedia, 6th ed. Copyright
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