When Top Gun Maverick released in 2022, viewers were astounded by a great scene in the beginning of the movie where the main character breaks Mach 10 in a prototype hypersonic jet. This jet doesn't actually exist in real life, and hypersonic vehicles remain limited to very few testing vehicles today. The current speed record for a crewed, powered aircraft, wasn't actually set by the SR-71 Blackbird as many people assume, but the X-15 in 1967 which reached Mach 6.7. The most important difference between the SR-71 and the X-15 is the propulsion system. The X-15 used a rocket-powered engine and the SR-71 used an after-burning turbojet, but neither of these solutions are cost-effective and efficient enough for hypersonic travel. The answer lies in today's topic, ramjets and their supersonic derivative, scramjets. In the constant race to go faster, aircraft designers have typically been restricted by a major limiting factor, the propulsion system. At first, it was the propelle...