The Space Race gave rise to a great number of experiments beyond orbital flights and lunar missions. One of them was the aircraft North American X-15, whose first flight took place on June 8, 1959. The X-15 completed 199 official flights during its nine years of activity, breaking multiple records in the process, including that of speed. How fast did it fly? According to available records, the X-15 shattered the 7,000 kilometers per hour barrier...
The X-15 vs. the SR-71 Blackbird
When searching for the fastest aircraft in the world on the Internet, the logical find is the SR-71 Blackbird. Indeed, it is the fastest, as long as we classify the data according to the flight technology used. The SR-71 is a crewed vehicle, and has air intakes, two details that place it as a leader in its own category. Now, if what we want is the fastest crewed aircraft regardless of its propulsion, the correct answer is the North American X-15. Designed from a concept created by Walter Dornberger (critical piece in the development of the V-2, transferred to the United States under Operation Paperclip), the X-15 program began its activities on June 8, 1959, and through the cockpits of its three prototypes passed very high-profile pilots, among whom stands out none other than Neil Armstrong, with seven flights between 1960 and 1962.
https://www.youtube.com/embed/tZqsRSEYcbsLaunch and Flight Profile
Like other vehicles of the so-called X-Series, the X-15 could not take off on its own, and had to be lifted to an average altitude of 13.7 kilometers with the help of a modified B-52. In other words, the X-15 was fired like a missile in all its missions. Official records report a total of 199 flights between June 1959 and October 24, 1968. Only two flights (90 and 91 of the general list) surpassed the Kármán line, both with Joseph A. Walker in the cockpit. The first was on July 19, 1963, with a confirmed altitude of 105.9 kilometers, and the second took place on August 22 of that same year, with 107.8 kilometers on the indicator.
The Speed Records
The fastest flights of the X-15 comfortably surpassed the 6,000 kilometers per hour mark; however, there were two occasions when it was taken to its most extreme limits, both with William J. Knight as pilot. Flight 175 on November 18, 1966, reached 6,840 kilometers per hour, while Flight 188 on October 3, 1967, firmly set the absolute record of 7,274 kilometers per hour. No crewed aircraft has challenged that number in the last 50 years, and given the current poor interest in the development of supersonic flights, it is most likely that nothing will change for a long time.
