Weird design of the world's fastest plane

Although first flown more than 60 years ago, the North American X-15 is still the world's fastest manned aircraft with its distinctive design, unusual take-off and landing behavior.
The X-15 is shaped more like a bullet than a regular plane, and it flies fast thanks to being a rocket in itself. The X-15 completed 199 test flights over nine years, starting in 1959.

The X-15 could fly to the edge of space and then glide back to Earth, collecting data that would inform the design and engineering of later US spacecraft, including the Space Agency shuttles. US headquarters (NASA).

The X-15 is flown by an elite crew of 12 pilots, including Neil Armstrong, who led the 1969 Moon landing.

'One of the X-15 pilots, Mr Bill Dana, once told me it gives you the greatest speed, the greatest excitement, the greatest terror. We haven't built anything like the X-15 since it's been in the atmosphere," Christian Gelzer, principal historian at NASA's Armstrong Flight Research Center, told CNN.

The Series X includes more than 60 experimental aircraft produced by US government agencies, including the Air Force and NASA, since the end of World War II in 1945.

In 1952, when development of the X-15 began, the official aircraft speed record was below 700 mph (1,126 km/h). The X-15's mission is to reach a speed of Mach 5 (5 times the speed of sound, which is nearly 4,000 mph or 6,437 km/h).

Mr Gelzer said: 'Such an aircraft would have to fly at 250,000 feet (76.2 km), higher than any aircraft at the time. It's a very difficult request'.

Project X-15 was led by the US Air Force and the National Advisory Committee on Aeronautics (NACA, became NASA in 1958).

'They follow the scientific data, the flight dynamics data. But in the context of the Cold War, research was accelerated," Gelzer said.

X-15 flies over the US state of California.

Rocket

Basically, the X-15 is a rocket with a cockpit. So, unlike other planes, it is not designed to take off from a runway. Instead, it was raised and dropped from the mother ship, in this case a specially modified B-52 bomber.

With the 50-foot X-15 under its wings, the B-52 took off from Edwards Air Force Base in California and flew toward Nevada or Utah, turning around and dropping the plane at 45,000. foot (13.7 km) and a speed of more than 600 mph (more than 965.6 km/h). Only at that point does the X-15 pilot activate the rocket engine so that the X-15 begins to break out of Earth's atmosphere and into space.

The fuel (a combination of ammonia and liquid oxygen) ignites in less than two minutes, and it's not a smooth flight. Mr Gelzer said: 'It flies aerodynamically like a normal plane, but when it's high it flies in an unruly horse. Milt Thompson, one of the pilots who flew the X-15, said it was the only plane he had flown where he was happy when the engines stopped working.

X-15 rests at Lake Rogers in California in September 1961 after performing a mission.

Glider

After the X-15 reached its target altitude (354,200 feet, or 108 km - 10 times the cruising altitude of a commercial airliner), the pilot conducted experiments in a then-unknown environment. arrived, helping experts gather data on supersonic flight.

Much of the X-15's design was geared toward being able to fly at high altitudes, where the air is so thin that conventional aerodynamic appendages no longer function. As a result, the X-15 was equipped with a reactive control system, similar to the reaction control system later used by the space shuttles and the International Space Station.

It spewed out streams of hydrogen peroxide (essentially water oxidized at very high concentrations), creating enough thrust to steer the plane through the thin layer of air in the upper atmosphere.

Flying at thousands of miles per hour, the X-15's outer shell becomes very hot due to aerodynamic friction and is therefore made of a special nickel-chromium alloy called Inconel X.

'The plane heated up to 1,200 degrees Fahrenheit (649 degrees Celsius). And the pilot could hear the expansion behind them," Gelzer said.

Landing the X-15 wasn't easy. 'From the moment the plane runs out of fuel, or the pilot turns off the engine, it's a glider. A very heavy, very fast glider with very small wings. So it's not a good roller coaster. At that point, the pilot had to rely on speed and altitude to get to the destination,' he said.

Worse still, the front wheels lacked steering and the main landing gear only had skids (two retractable steel beams that slid across the landing surface), so it was impossible to land on the runway. Instead, the plane had to land in a dry lake bed.

'By the time it returned to the ground, the plane was not the same as it had been when it left base. The fuselage appeared to have holes caused by the heat of combustion," Gelzer said.

The X-15 flew to the edge of space and then glided back to Earth.

Record

Most planes end up landing at speeds below 200 mph (354 km/h). However, the X-15 was able to initiate the landing process at 20,000 feet (6.1 km) and at supersonic speeds of more than 1,500 mph (2,414 km/h) - completely different conditions than the X-15. most of the pilots have gone through. Things don't always end well.

Mr Gelzer said: 'This is an experimental plane and things go awry almost every landing. What's remarkable is that the pilots managed to get the plane back on track, despite the problems they had."

Of the nearly 200 flights, only two crashed on landing, including one fatal incident. On November 15, 1967, pilot Michael Adams went into a spin during reentry, unable to keep the plane straight. In the end, the plane broke up in the air, killing the pilot.

The inherent risks of flying the X-15, half a plane, half a spaceship, is one of the reasons that the aircraft's record has never been beaten with modern technology. It is also a stepping stone to the space program, which has bigger ambitions than mere speed.

The X-15 is considered one of the most successful flight research programs ever undertaken, and in its nine years of operation it has collected countless data on high-speed, return-from-air flight. time.

In 1967, pilot Pete Knight achieved a record speed of 4,520 mph (more than 7,274 km/h), or Mach 6.7 (6.7 times the speed of sound).

The X-15 also spawned a generation of astronauts, including one of the greatest: Neil Armstrong. During one of his seven X-15 flights, Armstrong demonstrated the legendary problem-solving abilities that would eventually land him in command of Apollo 11.

Mr. Gelzer said: 'In 1962, Armstrong made a flight that took him to an altitude of 205,000 feet (62.5 km) and a speed of Mach 3.8 (more than 4,692 km/h). On the way back, he fell from the top of the atmosphere at about 90,000 feet (27.4 km) and slid like a rock. By the time the plane turned around, he was in suburban Los Angeles without power. He still managed to get the plane back and land in Rogers Dry Lake. It was the longest X-15 flight ever."

The X-15 still holds the record for fastest manned aircraft.

The North American X-15 set speed and altitude records in the 1960s, reaching the edge of outer space and returning with valuable data used in aircraft and spacecraft design. The X-15's top speed was 7,274 km/h (2,021 m/s), achieved on October 3, 1967, when William Knight flew at Mach 6.7 at an altitude of 31,120 m.

In the X-15 program, 12 pilots flew a total of 199 flights. Of these, 8 pilots flew a total of 13 flights that met the US Air Force's spaceflight criteria when exceeding an altitude of 80 km, thus qualifying to become astronauts. US Air Force pilots are eligible to become military astronauts immediately, while civilian pilots were recognized as NASA astronauts in 2005, 35 years after the X-15 flight. Final.