On Wednesday, April 29, 2026, U.S. company Lockheed Martin announced that retired engineer Denys Overholser had died the previous day at the age of 86. At the Skunk Works design bureau, he was responsible for developing the principles of radar cross-section (RCS) reduction technology, also known as low observability, or stealth, for military aviation.
Photo: Lockheed Martin
Denys Overholser, born in 1939, initially worked at Boeing on missile projects before later joining the Skunk Works design bureau within Lockheed Martin. The breakthrough came when he happened upon a book by Soviet physicist and mathematician Pyotr Ufimtsev, who in the early 1960s began developing mathematical models describing the diffraction of electromagnetic waves on two-dimensional triangular objects.
This led to the development of the Physical Theory of Diffraction (PTD). The Russians, however, did not foresee that it would have important military applications, so in 1962 they published its results in the book Method of Edge Waves in the Physical Theory of Diffraction, released by the Soviet Radio publishing house. In 1971, the book was translated into English under the same title.
In the middle of the decade, Denys Overholser came across it. Where other Skunk Works engineers saw only theory, he saw a solution. He understood that radar reflections could be precisely calculated and, more importantly, predicted before an aircraft was built. Ufimtsev had created a mathematical framework for analyzing the propagation of radar waves striking an aircraft, and Overholser extended his theory to three-dimensional objects. Ufimtsev himself had used formulas developed by a Scottish physicist and a German expert in electromagnetism.
Overholser’s work became the basis for the ECHO 1 computer program, which made it possible to model an aircraft’s radar signature. He developed the design of the Have Blue technology demonstrator, together with Richard Scherrer, Bill Schroeder, and Ken Watson, from which the groundbreaking Lockheed F-117A Nighthawk bomber later emerged under the leadership of Ben Rich’s team, establishing what we now call stealth technology. Later, Northrop used Ufimtsev’s work to program supercomputers to predict the radar reflection of the B-2A Spirit strategic bomber, to which the aforementioned Richard Scherrer also contributed.
Today we honor the life of Skunk Works® legend, Denys Overholser, who sadly passed away this week. His contributions helped shape the foundation of stealth, with his influence impacting decades of innovation. We extend our deepest condolences to his family.
— Lockheed Martin (@LockheedMartin) April 30, 2026