NASA LANGLEY RESEARCH CENTER 1917-2017
HIGHER, FASTER, FARTHER
Expanding Aeronautical Horizons By Craig Collins
In the early 1940s, as manufacturers began to produce aircraft that could travel several hundred miles per hour, the main challenge to high-speed flight was related to “compressibility effects:” Air flowed over airfoils and other surfaces at speeds faster than the aircraft’s velocity. At lower speeds, this wasn’t a problem, but when airflows reached “transonic” speeds, near and beyond the speed of sound, they created shock waves, which tended to proliferate until they hammered at the aircraft, creating drag and threatening stability. Because of these
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effects, the fastest World War II-era aircraft had difficulty flying much faster than 500 mph. Some engineers began to believe the “sound barrier” presented an insurmountable obstacle, an invisible wall in the sky. But this idea didn’t last long. Langley engineer Robert T. Jones, in 1945, independently developed the idea of the “swept wing” – commonly seen on jet fighters today – as a way to counter compressibility effects by deflecting the angle of the shock wave. Jones’ revolutionary idea didn’t get much attention at first, but
NASA PHOTO
Getting an airplane to fly faster had been a preoccupation for engineers at the Langley Memorial Aeronautical Laboratory from the moment flight research began there, but it wasn’t until World War II that aircraft speed became a matter of life and death. The war produced the world’s first jet-propelled aircraft, and though these jet fighters proved not quite ready to play a major role in battle, they were clearly the aircraft of the future. Langley engineers redoubled their efforts to evaluate materials, structures, configurations, and controls to enable aircraft to fly at ever-faster speeds.
