There were many next-generation planes at the Paris Air Show last week, but the one that was missing was the supersonic passenger jet. Still, the once and future dream of traveling from New York to L.A. in less than three hours is now getting a shot in the arm thanks to a new round of NASA funding.
Last week, the agency said it was putting $2.3 million into eight projects to overcome barriers to commercial supersonic flight. The announcement comes more than a decade after the Concorde completed the world’s last flight that carried paying customers two times faster than the speed of sound.
The goal of the new work is to make supersonic flight greener by reducing high-altitude emissions and to cut down on the noise from sonic booms, the extremely loud report from a shockwave created by an aircraft flying faster than 660 mph, the speed of sound at aircraft cruising altitude.
In 1947, the Bell X-1B rocket plane piloted by Chuck Yeager accelerated to 700 mph, or 1.06 Mach, and became the first aircraft to cross the sound barrier. The plane, which was powered by a rocket engine, was drop-launched from Superfortress bombers. Image credit: NASA
Sonic booms are considered such a potential public nuisance that the Federal Aviation Administration has banned civilian supersonic aircraft flights over land since 1973. The agency is now looking at changing this rule with research like that being funded by NASA, which shows that noise from booms can be significantly reduced.
“Lessening sonic booms…is the most significant hurdle to reintroducing commercial supersonic flight,” said Peter Coen, head of the High Speed Project in NASA’s Aeronautics Research Mission Directorate. “Other barriers include high-altitude emissions, fuel efficiency and community noise around airports.”
Concorde (above), developed by France and Britain, and Russia’s Tupolev TU-144 (below) were the first two supersonic commercial planes. Both planes were retired, but NASA used the Russian plane to study supersonic passenger transport. Image credits: Aero Icarus and NASA
Universities and companies are splitting the funding to work on projects like developing quieter nozzles, pilot interfaces to reduce the impact of supersonic overland flight, and studies of the environmental impact that supersonic flight might have on the stratosphere. Organizations like MIT, GE and the University of California are being funded to conduct research and development over the course of one to four years.
At GE’s Global Research Center in Niskayuna, N.Y., experts in acoustic, aerodynamic, fluidic and combustion technologies will focus on reducing supersonic jet engine noise during takeoffs and landings. Engineers say the noise coming from high-speed aircraft, even at the lower speeds they will be traveling during takeoff and landing, is a significant challenge that needs to be addressed. NASA awarded the company $599,000 for a two-year study period.
In the 1950s, Gerhard Neumann (left) and Neil Burgess developed the J79 engine, GE’s first supersonic jet engine that could travel as fast as twice the speed of sound. They hit on a breakthrough design that allowed them to modulate the amount of air coming inside the engine from the compressor. Today, the same technology is helping GE build more efficient jet engines and also gas turbines.
“GE has developed extensive high-fidelity simulation tools and design concepts for noise reduction in our commercial and military engines, and we now plan to leverage that technology to reduce propulsion noise for this application,” said Kishore Ramakrishnan, principal investigator on the NASA program and member of the Aerodynamics and Acoustics Lab at GE Global Research. “We also are teaming with Lockheed Martin to understand the impact of these concepts on overall aircraft performance and sonic boom characteristics.”
This image illustrates the density of a jet engine exhaust flow. GE engineers are using powerful supercomputers to study jet engines, increase their performance and reduce noise. The image was created on the Intrepid computer network at Argonne National Lab. Image credit: GE Global Research
Ramakrishnan says the company’s research will look to better fit the engine into the aircraft’s overall design to minimize noise. Engineers will also evaluate technologies that can reduce fan and jet noise coming from the engine itself. Part of that investigation will include producing advanced simulations that model the noisy high-velocity flow coming out of the engine’s exhaust nozzle, as well as noise from the fan radiating out through the inlet of the engine.
Company officials say these types of government-funded project are important to advance aviation into its next generation, where supersonic travel could become available to a wider swath of society.
This picture is a two-dimensional cut-away from the previous photo. Image credit: GE Global Research
“It’s truly amazing how far air travel has come over the past century,” said Narendra Joshi, Advanced Technology Program Leader for propulsion at GE Global Research. “It has shrunk the world in ways we could not even have imagined 100 years ago. But we need to continue to push forward, and it is great that NASA is leading the way and supporting industry in developing the innovations that are needed to make economic supersonic air travel possible.”