It wasn’t just a jet, it was an exclusive club – The mighty Concorde. The idea of supersonic flight- to travel at speeds faster than the speed of sound and because it’s extremely fast – had the potential to reduce time in the air and cut down hours off trans-oceanic flights, has always been appealing to man.
The quest to sustain sustainable supersonic travel has never been a bed of roses as it was always beset with challenges, right from regulatory hurdles to solving noise pollution. According to some experts, the idea of a green supersonic flight is almost self-contradictory. The Concorde, they note, was pretty terrible in terms of emissions.
Nearly two decades now, after the Concorde was retired, the race is still on to get the supersonic birds up and flying again.
Lockheed Martin has now released footage which provides a new update on the X-59 aircraft it is developing in collaboration with NASA. In the video, Michael Buonanno- the X-59 Air Vehicle Engineering Lead, says the aircraft has successfully undergone two crucial tests, a structural proof test and a fuel system test that showed the aircraft measures fuel accurately. And now that makes it ready for its first flight test.
What is the X-59 and why build a quiet supersonic aircraft?
The X-59 Quiet SuperSonic Technology (QueSST) is a collaboration between NASA and Lockheed Martin designed to fly faster than the speed of sound-“quietly”.
Supersonic flights are synonymous with the iconic “sonic boom” and that’s one of the reasons why commercial supersonic flights are banned in the US.
What is a sonic boom?
A sonic boom is the result of compressed pressure waves at the front and rear of the aircraft merging into a singular shockwave as they can no longer get out of the way of each other before they reach the ground.
To get a perspective, consider the crack of a bullet, which has the same effect as a sonic boom, although on a much smaller scale. The shockwaves are known to cause hearing damage in veterans. Now scale it a notch higher, to the size of a jet, and it becomes capable of causing structural damage and noise of up to 120 decibels. Therefore commercial supersonic jets flying overhead have the potential to shatter windows in their path, and hence supersonic flight above land is prohibited.
The X-59 is Lockheed Martin and NASA’s answer to the ever-prevalent sonic boom issue. Current commercial airliners typically fly at a speed of 460-575 miles per hour at a cruising altitude of about 36,000 feet. The X-59 is designed to see how it can endure the challenges of supersonic speeds, so it only yields a more desirable “sonic thump” instead of the unsettling sonic boom.
The “sonic thump’, while still not ideal enough, is touted to significantly reduce the noise and potential damage created by a sonic boom, which both Lockheed Martin and NASA hope will allow the ban on overland supersonic commercial flights to be lifted.
Digital engineering has been integral to the design of X-59 since its earliest stages. Unlike traditional aircraft where we extensively used wind tunnels to shape and understand the flow around the configuration. We use thousands of computer simulations to characterize the nuance of every single flow feature on the aircraftBuonanno explains
Tony Delagarza, who lead the X-59 Finite Element Analysis team, underscored the role of aeroelastic modelling that helped achieve the required “quiet” boom levels. According to Delagarza, the X-59’s supersonic boom would be comparable to a “car door slamming” in comparison to the Concorde’s massive supersonic boom which could “shatter windows”.
With the X-59, we want to demonstrate that we can reduce the annoying sonic booms to something much quieter, referred to as “sonic thumps”. The goal is to provide noise and community response data to regulators, which could result in new rules for overland supersonic flight. The test proved that we don’t just have quieter aircraft design, but that we also have the accurate tools needed to predict the noise of future aircraftsaid John Wolter, lead researcher on the X-59 sonic boom wind tunnel test
The X-59 is scheduled to fly later this year, that is, if everything goes by as planned. Further acoustic validation flights are planned for 2023 followed by community overflights in early 2024 to test the loudness of the sonic boom.
NASA plans to deliver results of the community overflights to the International Civil Aviation Organization and Federal Aviation Administration in 2027. With that information in hand, regulators will be able to decide if a change should be made in rules that prohibit supersonic flight over land- a decision that would be expected in 2028NASA
What do you think will be the fate of commercial supersonic air travel this time around? Will history repeat itself as we’ve seen in the case of Concorde? With private players entering the supersonic arena and billions being invested, do we have a new supersonic jet-age coming?
COVER: Wikipedia Commons