F‑117 nighthawk: The stealth bomber that never really retired

On 18 June 1981, an extraordinary aircraft took to the air. Its shape defied aerodynamics—rather than a smooth, streamlined fuselage, the machine consisted entirely of flat surfaces, forming a somewhat awkward, angular structure.

This was neither a coincidence nor a whim of the creators but a necessity arising from the limited computational power of the time. The shape of the aircraft's fuselage was modelled digitally, which imposed restrictions on rounded surfaces and the number of elements forming the fuselage and wings.

Like many other revolutionary machines of its time, the F-117 Nighthawk was developed at Skunk Works—a division of Lockheed Martin where the most talented engineers worked on unconventional aircraft without the constraints of corporate procedures or hierarchies.

The Soviets helped construct the F-117. This was due to a scientific paper published by Russian physicist Pyotr Ufimtsev, the creator of the Physical Theory of Diffraction (PTD), which studied how electromagnetic waves refract at the edges of obstacles.

Since the USSR did not see the potential of this research, the results were published in 1962 in the book "Method of Edge Waves in the Physical Theory of Diffraction", translated into English in 1971.

A Lockheed engineer, Denys Overholser, came across it and realized that Ufimtsev's research could be used to analyze radar waves striking a flying aircraft and design the shape of the machine so that it reflects the radar signal in such a way that it does not return to its source.

The world owes the creation of the F-117 to Overholser's persistence. The machine was so innovative and different from anything built before that even at Skunk Works, the idea of its construction met with serious resistance.

The main opponent of the new aircraft was Kelly Johnson—an engineer responsible for creating aircraft such as the P-38 Lightning and the SR-71 Blackbird. According to this aviation veteran, the aircraft design proposed by Overholser had no right to stay in the air.

It was true; a human could not pilot the Have Blue aircraft, the demonstrator of the later F-117. Therefore, a computer was used to correct—independent of the pilot—the position of the aerodynamic surfaces several times per second based on the flight parameters.

The solution proved effective—the "crumpled beverage can" aerodynamics machine could stay in the air and respond correctly to control movements.

The F-117 Nighthawk made its first flight in 1981, and just two years later, it began official service in the American Air Force. Although it was a bomber, it was given a misleading designation suggesting it was a fighter (F—from fighter). A total of 64 units were produced, 59 in the serial variant.

In subsequent years, the F-117 participated in the attack on Grenada, the Desert Storm operation, NATO intervention in the Balkans, and the "war on terror," attacking targets in Iraq and Afghanistan.

Although in the 1980s, the F-117 was secret, aviation analysts and enthusiasts predicted its existence. However, they assumed the aircraft would be named F-19 (which was reflected, for example, in a video game—a flight simulator developed by MicroProse in 1988).

After the F-117's official existence was confirmed in 1988, experts disagreed on its performance. For example, the Swedes, based on photographs, estimated that the F-117 could reach speeds of Mach 3. This was not true.

The F-117 is a single-seat bomber with a take-off weight of 24,000 kilograms, of which just over 2000 kilograms account for the weaponry carried in internal bays. The aircraft is 20 meters long, has a wingspan of 13 meters, and has an unconventional aerodynamic design with a V-tail.

The F-117's maximum speed is Mach 0.92—it is a subsonic machine. The aircraft can reach an altitude of 10,000 meters and has a range of 3000 kilometres, which can be extended by in-flight refuelling.

A shadow over the legend of the "invisible" aircraft was cast in 1999 when an F-117 was shot down over Kosovo by Serbian anti-aircraft forces. Their success is even greater considering they shot down the American machine using an outdated (though modernized) S-125 Neva anti-aircraft system.

This was possible because—as post-incident analyses showed—Americans disregarded precautionary measures and flew the same route multiple times. Although the time during which the F-117 was tracked was too short to guide the missiles to their target, Serbians could estimate the aircraft's position and fire upon the space where—according to calculations—the American machine was supposed to be.

Although no direct hit was achieved, the 60 kg warhead's explosion occurred close enough to the aircraft to critically damage its control surfaces and cause the machine to crash. Based on this incident's experiences, the F-117's software was modified to keep the aircraft in the air despite the damage.

F-117 aircraft were formally retired from service in the American Air Force in 2008. Nonetheless, the "invisible" machines were not grounded. At least some of them retained the ability to fly, and unofficial reports in subsequent years suggested that F-117s continued to fly and perform some undisclosed tasks.

The atmosphere of mystery was fueled by sightings of F-117s in the Area 51 region. This is an American military testing ground where the latest—also classified—designs are tested, associated by pop culture with the UFO crash and technical secrets allegedly hidden by the U.S. government.

In 2019, there were reports—and they were not confirmed by the Pentagon—of several machines being moved to the Middle East. It wasn't until 2021—with new photos—that it was officially confirmed that F-117s are still in use.

According to the Pentagon, the F-117s currently serve a training role. With their shallow radar cross-section (i.e., surface from which radar waves can reflect), Nighthawks today simulate hard-to-detect machines of potential U.S. adversaries, such as the Chinese J-20 or the Russian Su-57, allowing pilots of other American aircraft to practice countering stealth planes.