Incredible images of an Air Force jet passing in front of the sun has revealed how NASA will visualize shockwaves of a future supersonic X-plane it hopes will pave the way for future passenger jets.
NASA’s Armstrong Flight Research Center in California captured the images of its Test Pilot School T-38 as it transitions from subsonic speed to supersonic using a technique called schlieren photography.
The agency said it brings them one step closer to being able to visually capture the shockwaves of its future supersonic X-plane, also know as a Low Boom Flight Demonstration aircraft (LBFD).
Incredible images of an Air Force jet (pictured) passing in front of the sun has revealed how NASA will visualize shockwaves of supersonic planes. The agency said it brings them one step closer to being able to visually capture the shockwaves of its future supersonic X-plane, also know as a Low Boom Flight Demonstration aircraft (LBFD).
NASA on Monday released the images that show the Test Pilot School T-38 (pictured) as it transitions from subsonic speed to supersonic using a technique called schlieren photography
The Quiet Supersonic Transport (QueSST), or X-plane, aims to produce a much lower ‘boom’ than other supersonic aircraft at speeds beyond Mach 1.
NASA is hoping to see the first flight tests take place around 2021, and when this happens, imagery to confirm that the future X-plane’s shockwaves match NASA’s predictions will need to be captured.
The schlieren photography technique was used in a series of flights in 2016 called Background Oriented Schlieren using Celestial Objects (BOSCO).
BOSCO used a special hydrogen alpha filter, and positioned cameras to use the sun as a background, to visualize shockwaves from supersonic aircraft eclipsing the sun 40,000 feet from the camera.
Placing the cameras on the ground enabled the use of full-sized telescopes, which were used to maximize the size of the sun image on the camera, according to NASA.
But the LBFD will be flying at altitudes around 60,000 feet, and in order for shockwave data to be captured at a high quality, images will need to be taken at closer range, by equipment onboard a chase aircraft.
In other words, the photography equipment will need to be small enough to fit in a wing pod, but still have the ability to take high-quality images of shockwaves.
And recents tests completed by BOSCO flights, or BOSCO II, accomplished just that.
In addition to validating the quality of smaller equipment, BOSCO II successfully applied this photography method from a range of 10,000 feet, similar to the range needed for an air-to-air system when LBFD flies, according to BOSCO II Principal Investigator Mike Hill.
‘The main objective here was to see what the image looks like at close range, including what kind of shockwave structure we can make out,’ Hill stated.
‘We needed to use our new compact camera system in order to get an idea of the quality of the images of those shockwaves using a smaller system.’
The BOSCO II flights were flown using the T-38 aircraft and a NASA F-15. In order for accurate images to be captured, pilots had to be in a precise location at a low altitude of 10,000 feet, directly between the cameras on the ground and the sun, and all while flying faster than Mach 1.
‘This wasn’t an easy task for our pilots, but they hit the mark,’ Commercial Supersonic Technology Sub-project Manager Brett Pauer noted.
Recent flight tests have confirmed the quality of the images taken on a smaller photography system, and provided insight into how to optimally operate these imaging systems at close range
Now, flightworthy hardware can be developed and integrated into a high-speed NASA chase aircraft to be able to capture similar images when LBFD takes flight.
In June NASA announced that it plans to begin work on the supersonic X-plane as early as next year.
Lockheed Martin has been working on the preliminary design, with hopes to move on to build the demonstrator, but NASA also opened the door for other companies to submit their own designs as well.
The space agency is hoping to achieve a sonic boom 60 dBA lower than other supersonic aircraft, such as the Concorde, which was a turbojet-powered supersonic passenger jet that was operated until 2003.
The Quiet Supersonic Transport (QueSST) low-boom flight demonstrator (pictured) aims to produce a much lower ‘boom’ than other supersonic aircraft, and NASA is hoping to see the first flight tests take place in 2021
NASA is looking for plans to develop, build, and flight test an X-plane, and will award a contract in 2018.
It’s been decades since NASA has worked on a manned supersonic X-plane, and after the contract is awarded in 2018, the winning team will undergo critical design review in 2019 to bring the plan closer to life.
Then, the agency plans to see the first flight tests in the first quarter of 2021.
For the most part, the demonstrator tests will take place across two phases at the Armstrong Flight Research Center in California, and culminating at the base housing at Edwards AFB.
The first will focus on aircraft build, checkout, and supersonic flight envelope expansion set for late 2021, followed by efforts focusing on low-boom acoustic validation, according to Aviation Week.
NASA hopes the low-boom X-plane (pictured) will support changes in FAA regulations, to allow supersonic flight over land. Whenever an aircraft flies supersonic, or faster than the speed of sound, it produces shockwaves that is eventually heard on the ground as a loud sonic boom. This is the driving factor behind the FAA’s restriction on supersonic flight over land
BOSCO Chief Engineer Brian Strovers and research engineer Paul Dees calibrate one of three cameras positioned to capture images of supersonic research aircraft
Then, in 2022, researchers will assess the ground signature of the demonstrator, and the effects on atmospheric and flight conditions from the boom.
NASA is hoping the low-boom X-plane will support changes in Federal Aviation Administration (FAA) regulations, to allow supersonic flight over land.
Whenever an aircraft flies supersonic, or faster than the speed of sound, it produces shockwaves that is eventually heard on the ground as a loud sonic boom.
This is the driving factor behind the FAA restriction on supersonic flight over land.
NASA intends to demonstrate quieter supersonic flight through the LBFD, and should the quiet thump of the shockwaves prove to be within acceptable limits to the FAA and communities on the ground.
According to predicted sound levels, it may open the future to supersonic flight over land on a commercial level, potentially cutting flight times in half.