US Air Force and Pentagon want hypersonic planes that can cross the globe in 4 hours by 2023

The US Air Force has decided to team up with the Department of Defense to speed up the development of hypersonic aircraft and hopes to achieve its goal by 2023. Hypersonic refers to any aircraft that travels at five times the speed of sound, which is about 3,800mph and known as Mach 5. In order to achieve this, the plane needs to be lightened using Supersonic Combustion Ramjet Engines (Scramjet) technology.

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