The “revolutionary” air-breathing engine could, in theory, lift an aircraft from a runway to more than 30km (18.6 miles) into the stratosphere and continuously accelerate it to 16 times the speed of sound.
At this velocity, even the longest intercontinental flights could take just one or two hours while consuming less fuel compared with conventional jet engines.
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Outside, why wear a hat if no one can see it ?
Aerodynamics.
That’s why cowboy hats have folded brims.