To be able to successfully break through the sound barrier, an aircraft’s engine and airframe must be designed to overcome the adverse effects of supersonic flight. Wingspan must be limited but wide enough to remain aerodynamically efficient at slower speeds. The airframe must be able to withstand the intense heat that is generated from friction as air rapidly flows across its surface. Additionally, the engine must be able to produce enough thrust to counter significant drag. //

NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA), believed that it was possible for propeller-driven aircraft to break the sound barrier eventually. In the 1940s, NACA invested heavily in new designs for propellers through a high-speed propeller research program. Over time, it was able to design propeller blades capable of reaching Mach 1.0. This was accomplished by shortening and thinning the blades, sharpening the leading edges, minimizing camber, and increasing the blades’ angles.

While the change was an overall success, parts of the blade would reach supersonic speeds before others. This was problematic for two reasons—first, sonic waves are created when an object nears the speed of sound. Because the blades were reaching Mach 1.0 unevenly, they were creating pockets of sonic waves powerful enough to destroy the propeller. Second, another problem was noise. Propeller-driven aircraft are loud enough, but when those spinning blades reach supersonic speeds, the noise level generated becomes a threat to the structural integrity of the aircraft—and its pilot.

The propeller-driven XF-88B Voodoo, which was fitted with turbojets and a T-38 turboprop engine, was NACA’s experimental aircraft of choice. Unfortunately, just as it was on the brink of success, the agency abandoned the project. By this point, Yeager had made history, and advancements in jet engine technology had effectively crushed any interest in high-speed propellers.