On a clear August morning in 1979, in the Nevada desert, a detachment of Marines armed with the newest generation ground to air missile system on the US arsenal, the HAWK, tried to score a hit against a new bird. The system was so sophisticated that it could detect flak of incoming hawks with only their thermal imagery. In order to make the excursive more intriguing, the people who designed and developed the new plane gave the detachment the exact incoming fly pattern of the airplane. Where it was coming and where it was headed. With this information, the Marines just needed to point the missile system toward the incoming direction of the plane, and the HAWK would arm itself and destroy the incoming threat. At precisely eight o’clock in the morning, the prototype of what was to become the world’s first true stealth plane, the F-117 Nighthawk Fighter-Bomber, appeared over the sunny skies of the Nevada desert. Completely undetected by the world’s most sophisticated anti-aircraft missile system. It was an amazing triumph of designing engineering.
The real truth about the journey from advanced conventional jet designed aircraft to complete stealth was one with many turns. Big triumphs and even bigger failures. One that originated back in the mid 1930s and progressed in an obscure form for the next forty years. That’s until the US Air Force considered the possibility of deploying bombers that were hard to see in radar to strike at the Soviet Union. A bombing platform that could penetrate the most densely designed anti-aircraft system in history. After the Arab-Israeli War of 1973, and after seeing the casualties list of Israeli warplanes gone down by Soviet made surface to air missiles, the US military started a crash course in the feasibility of a bomber designed invisible to the current and future radar systems. They put out a request for the design of a radical new plane. At the end of the summation process, the legendary Lockheed’s Skunk Works, the developers of the U-2 spy plane and the world’s first near stealthy airplane, the SR-71 Blackbird; was handed the assignment of designing, developing and producing a completely stealthy plane.
After years of top secret research in the designed shape of the airplane, Skunk Works was at an impasse. The mathematics of stealth fuselage design did not match with the reality on the field. They needed a new approach. This was delivered by a once obscure radar expert at Lockheed, Denys Overholser. He put forward to the design team an even more obscure paper, wrote in the mid-to-late 1960s by a Russian mathematician. Pyotr Ufimtsev was a top scientist in the Moscow Institute of Radio Engineering, the paper he wrote: Method of Edge Waves in the Physical Theory of Diffraction, was fully loaded with mathematics as well as scientist terms and phrases that its translation from Russian took well over seven years after it first surfaced in the West. After carefully reading and deciphering the almost forty page document, the design team realized what they had in their hands, that it could be the breakthrough they needed. The most important section of the study was at the end of the paper. That part was a revisit of an early study produced by a Scottish physicist, Dr. James Maxwell and later remade with new data by the brilliant German electromagnetic expert, Arnol Somerfeld. Their calculations almost completely predicted the way that a specific geometric configuration would reflect electromagnetic radiation. The paper raw information was primarily used in the design of computer software to be implemented in the collection of radar signature data from various wings and fuselage shapes. This data was put to great use in the upcoming development of the airplane wings and main fuselage. The study opened a new door to understanding shapes and their importance in the development of a truly stealthy aircraft. With the data obtained as a direct result of computer system experimentation and, of the Ufimtsev’s paper information, Skunk Works was able to accurately calculate the radar cross section of any surface. This gave the design team the final data needed to go forward with the ultimate design of this amazing aircraft, the F-117 fighter-bomber. Now, as the F-117 enters it’s retirement phase, the plane is due to be replaced by the new F-22 Raptor.
