Extreme heat is one of the main challenges in developing aircraft capable of traveling at very high speeds. Now, scientists have identified a “super material” that could help overcome this obstacle and potentially make ultra-fast air travel possible.
Hypersonic flight is defined as speeds of Mach 5 (about 6,174 km/h) or faster. For comparison, the Concorde had an average cruising speed just above Mach 2, while the fastest manned aircraft ever flown—the experimental North American X-15—reached Mach 6.7 in October 1967. More recently, Boeing tested the X-51A supersonic aircraft in 2013, which achieved Mach 5 but maintained that speed for only about 210 seconds.
Despite these milestones, no aircraft has yet managed to provide sustained hypersonic travel comparable to the relatively accessible passenger flights once offered by Concorde. Researchers supported by the U.S. Air Force are now exploring new approaches to make this possible.
The Air Force has co-funded a research project conducted by NASA, Binghamton University, and the State University of New York. Their findings could mark an important step toward aircraft capable of maintaining hypersonic speeds—Mach 5 or faster—for extended periods.
An aircraft traveling five times the speed of sound could theoretically fly from London to New York in less than an hour. However, achieving such speeds requires solving several major engineering challenges. One of the most critical is developing materials that can withstand the extreme heat and mechanical stress generated during hypersonic flight.
The researchers have developed a new material based on boron nitride nanotubes (BNNTs). Previously, carbon nanotubes have been considered promising for aerospace applications because they are lightweight, stronger than steel, and capable of withstanding high temperatures. However, boron nitride nanotubes appear to outperform them in several key areas.
According to the research team, the new material is both exceptionally strong and extremely lightweight, potentially enabling aircraft capable of traveling between five and ten times the speed of sound.
While carbon nanotubes remain stable at temperatures of up to about 400°C, the study found that boron nitride nanotubes can withstand temperatures approaching 900°C. They are also able to tolerate significant mechanical stress while maintaining structural stability.
Despite their promise, it may take up to a decade before boron nitride nanotubes are widely used in aircraft. Production remains limited, and NASA currently operates one of the few facilities capable of manufacturing the material at high quality.
At present, BNNTs cost roughly $1,000 per gram. However, researchers expect the price to fall significantly as production methods improve. Carbon nanotubes once had a similar price but now cost around $10–20 per gram thanks to technological advances and larger-scale manufacturing.
The research paper, “Quantitative Characterization of Structural and Mechanical Properties of Boron Nitride Nanotubes in High-Temperature Environments,” was published in Scientific Reports.
Reference:
Chen, X., Dmuchowski, C. M., et al. Quantitative Characterization of Structural and Mechanical Properties of Boron Nitride Nanotubes in High-Temperature Environments. Scientific Reports. DOI: 10.1038/s41598-017-11795-9.