Nasa to begin tests for its ‘quiet’ supersonic X-plane that could fly from London to New York in 3 hours without producing a loud sonic boom
Nasa is set to begin tests for its 1,100mph (1,770kph) ‘Son of Concorde’ commercial jet that can travel from London to New York in just three hours. The plane, dubbed the Quiet Supersonic Transport (QueSST) low-boom flight demonstrator (LBFD), aims to cut out the noise associated with supersonic travel. Flights conducted by Nasa in November will study the US public’s reactions to ‘quiet’ supersonic noises, a researcher has revealed.
‘This project, QSF 18, is a test so we can test the methodology for future community response testing for projects like the LBFD,’ said Larry Cliatt, principal investigator for Nasa. LBFD aims to cut out the noisy sonic booms that echoed above cities in the era of Concorde, while travelling at speeds of 1,100mph (Mach 1.4 / 1,700 km/h).
The loud booms that rang out whenever a Concorde aircraft broke the sound barrier were often described as ‘unsettling.’ LBFD, which Nasa is developing with Lockheed Martin Aeronautics Company, will make its first flight in 2021 if production goes according to plan. The team hopes to reduce the sound of the sonic boom to a quiet thud, similar to the sound of thunder rumbling in the distance or a neighbour closing their door. Before LBFD’s first flight Nasa intends to simulate the sounds to gauge public responses to the aircraft’s sonic booms. With low boom flights, Nasa said it ‘intends to gather data on how effective quiet supersonic technology is in terms of public acceptance.’
Tests scheduled for November will see an F-18 fighter jet conduct a dive manoeuvre off the shores of Galveston, Texas – an island city near Houston. The plane will dive 49,000 feet (15,000 metres), briefly going supersonic and firing off the sound likely to come from LBFD aircraft.
‘It’s extremely exciting, and I expect the Galveston people will be excited, as well,’ Mr Cliatt said. QueSST is the latest addition to the X-series of experimental aircraft and rockets, used to test and evaluate new technologies and aerodynamic concepts. Their X designation indicates their research mission status within the US system of aircraft naming.
This all dates back to Chuck Yeager’s sound-barrier-breaking craft, the X-1, a rocket engine–powered aircraft, designed and built in 1945, that achieved a speed of nearly 1,000 miles per hour (1,600 kmh) in 1948. Nasa’s vision for the LBFD was approved In the latest proposed US budget released by the Office Of Management And Budget In Washington, DC, in February.
The space agency was awarded $19.9 billion (£14.3bn) for the next year, $500 million (£360m) more than the previous year. It is not known what proportion of this will be spent on the supersonic aircraft project. QueSST will be used as a test bed for technologies that could make their way into commercial planes.
Writing in the latest budget, its authors said: ‘The Budget fully funds the Low-Boom Flight Demonstrator, an experimental supersonic airplane that would make its first flight in 2021. ‘This ‘X-plane’ would open a new market for US companies to build faster commercial airliners, creating jobs and cutting cross-country flight times in half. ‘
The space agency is hoping to achieve a sonic boom 60 dBA lower than other supersonic aircraft, such as the Concorde, a turbojet-powered supersonic passenger jet that was operated until 2003.The QueSST low-boom flight demonstrator (LBFD), or X-plane, aims to produce a much lower ‘boom’ than other supersonic aircraft at speeds beyond Mach 1. It is designed to fly at Mach 1.4 (1,100mph / 1,700 kph), 55,000 feet (10 miles) above the ground. The aircraft is shaped to separate the shocks and expansions associated with supersonic flight to reduce the volume of the shaped signature, and was developed by Lockheed’s Skunk Works over 20 years.
Recent research has shown it is possible for a supersonic airplane to be shaped in such a way that the shock waves it forms when flying faster than the speed of sound can generate a sound at ground level so quiet it will hardly will be noticed by the public, if at all.
The space agency is hoping to achieve a sonic boom 60 dBA lower than other supersonic aircraft, such as the Anglo-French Concorde. In a written statement, a Nasa spokesman previously said the aim was to create a boom ‘so quiet it hardly will be noticed by the public, if at all… like distant thunder [or] the sound of your neighbour forcefully shutting his car door outside while you are inside.’
It’s been decades since Nasa has worked on a manned supersonic X-plane, and after the contract is awarded, the winning team will undergo critical design review in 2019 to bring the plan closer to life.
Nasa is hoping to see the first flight tests take place in the first quarter of 2021.
