What was it like to steal the world's most nasty airplane?

The X-15 was not the first rocket powered aircraft, but it is probably the best aircraft ever built and flown. Before the first flight of the X-15 in the late 1950s, the fastest speed of the planes was Mach 3. The X-15 double this. And, remarkable thing, he has also flown in space more than a dozen times.

The US Air Force and NASA have developed the X-15 to better understand flight in extreme conditions, including re-entry into the Earth's atmosphere. Yet more than half a century later, this exceptional aircraft still holds the world speed record recorded by a piloted and powered aircraft after William Knight piloted the vehicle at Mach 6.70 in 1967.

The X-15 program also includes an exclusive club of pilots: only a dozen airmen can claim to have flown the plane, which represents 199 flights in total. (They were all men, given the time.) Before landing on the Moon, Neil Armstrong made seven X-15 missions between 1960 and 1962. The film First man Highly depicts one of these flights.

Another X-15 pilot, Joe Engle, has also embarked on a remarkable career at NASA. Scheduled to land on the Moon during Apollo 17 alongside Eugene Cernan, Engle was fired from this mission for essentially political reasons, so that a scientist, Harrison Schmitt, could be added to the final mission of # 39; Apollo. Later, Engle will command the second space shuttle mission.

Engle is also the last of the X-15 drivers still alive. On the occasion of the 60th anniversary of the X-15's first motorized flight, in which Scott Crossfield took the aircraft to 52,000 feet on September 17, 1959, Ars spoke to Engle about flying the meanest plane. of the world. Spoiler alert: it was thrilling.

NASA nixée

Engle graduated from the US Air Force Test Pilot School in 1961 and served in the Hunter Test Group at Edwards Air Force Base in California. Two years later, as NASA's efforts to send humans to the moon began to gain ground, Engle and many other Air Force test pilots, such as Mike Collins, asked to become an astronaut in the United States. In the summer, Engle recalls being summoned to the office of the Air Force Test Center Commander at Edwards, Major General Irving Branch, a legendary figure who led the raids. bombing in the Pacific during the Second World War.

As he made his way to the branch office, Engle tried to figure out what he could have done wrong. Branch ordered Engle to sit down when he entered. "I see you applied for the NASA astronaut program," Engle said. "Do not like it here?"

The test pilot admitted that he had applied to NASA for his third class of astronauts. It seemed like the next logical step in his career, and he liked the idea of ​​going to the moon. That did not appease Branch. In his story, Engle said that Branch had suspended its application to NASA and had been torn in half.

"Well, I think I'm just going to disapprove of it," Branch said.

After this rude meeting, Engle said that he had spent a lot of time trying to figure out what he could have done to thwart the boss. A few weeks later, Engle learned that one of the base's X-15 pilots, Robert White, was rotating the program. Engle had to be his replacement.

A year earlier, White had flown the X-15 at an altitude of 95 km, for the first time crossing the threshold of the Air Force for space flights in the experimental aircraft. This white qualified as an astronaut. Now, Engle was very likely to follow in his footsteps.

Enter the cockpit

After joining the X-15 research program, Engle flew his first free flight in October 1963. He completed 16 missions in two years, for a maximum of 85.5 km above the US threshold. Air Force. to be considered an "astronaut". He also reached a maximum speed of Mach 5.71.

Once selected for a particular mission, Engle said that a pilot would spend most of his waking hours in a simulator or with test engineers to understand the data he was hoping to get from him. a particular flight. They also trained extensively on the Lockheed F-104 Starfighter aircraft, particularly in the dry grounds of the lake, near Edwards Air Force Base, in the event of an engine failure during an X-15 mission.

The engineers had two basic flight profiles for which they wanted to collect flight data. On a flight designed for higher altitudes, the X-15 would release its B-52 aircraft, fire the engine from its rocket and fly upwards at an angle as steep as 45 degrees. This would provide enough energy and lift to send the aircraft on a 107-kilometer ballistic flight. During such a flight, the X-15 would collect data on atmospheric reentry. The other profile, in which the X-15 was launched at an angle of about 30 degrees, stabilized around 30 km. During these flights, the engineers searched for data on high speed or overheated flights due to airflow shocks around X-15 surfaces.

The night before a flight, the technicians mated the X-15 to the B-52, pressurizing the fuel tanks of the aircraft and preparing it for flight. As a pilot, Engle would arrive shortly after sunrise to don a protective suit and ensure the integrity of his seals. About 45 minutes before takeoff of the carrier aircraft, he climbed into the cockpit of the X-15 and connected to the survival center.

Then the wheels rolled and the B-52 took off for its bumpy ride to the launch point and at an altitude of 13.7 km. It would take a little over an hour, during which time Engle would continue to look at his memory cards. In particular, he memorized various dry lake bottoms that he could use if there was an engine failure aboard the X-15, depending on the number of seconds the engine had burned before falling off. Out of order. During the rare moments of reflection of that time, he does not remember being nervous. On the contrary, he said, "You are delighted to die having the opportunity to be there."

Image illustrated by the US Air Force