After minimizing sonic boom, reducing airport noise is seen as the next biggest barrier to commercially viable future supersonic transports. As it works toward flying an X-plane in 2019 to demonstrate low-boom design technology, NASA is conducting ground tests of an engine nozzle that could make a small supersonic airliner as quiet as current subsonic transports.The model tests underway at NASA’s Glenn Research Center will validate design tools and concepts for an integrated propulsion system that would enable a quiet supersonic airliner with the seating capacity of a regional jet to have a cumulative noise level 10 EPNdB below current Chapter 4 limits.
Nasa has decided to invest $2.9m (£2.19m) in order to realise an innovative plane concept invented by MIT and Aurora Flight Sciences in 2008 which could make subsonic planes much more efficient than they are today.The Aurora D8, which flies at a speed of Mach 0.764 (582 mph, 936 km/h), was originally developed by Aurora Flight Sciences and MIT as part of Nasa's N+3 Program, which provided funding of technologies for new aircraft that would be substantially more efficient to aeroplanes today, that would be put into service in the 2030s.
Rather than chasing supersonic flight with quiet sonic booms, wouldn't it be more effective for NASA to be working on an integrated travel infrastructure that eliminates these bottlenecks? As long as getting from home to the aircraft and the aircraft to the final destination is not considered part of air travel, supersonic flight will not speed up the process. The problem these days is not slow planes, it's a kludged-together transport system.
NASA will soon ask companies to bid for a contract to build a supersonic X-plane whose preliminary design review was completed on 23 June by Lockheed Martin.
It also will serve as a testbed for other technologies. Instead of a forward windscreen, the X-plane pilot will view the aircraft’s forward path from a ultra high-definition video produced by a camera installed in a fuselage-mounted fairing, says David Richwine, who managed the preliminary design project called the Quiet Supersonic Transport (QueSST).
A newly-released rendering of Lockheed’s preliminary design reveals other features of the highly-swept, delta-wing jet. A row of eight vortex generators are arrayed over the top of the fuselage just aft of the cockpit and a set of moving forward canard surfaces.
NASA remains committed to its goal of returning to X-plane flight demonstrators, but at a slower pace that has some in industry concerned about their priority and relevance.When the agency unveiled its New Aviation Horizons initiative in 2016, it planned a sequence of X-plane programs initiated as frequently as 18 months apart. But NASA did not receive the significant boost in aeronautics funding it sought, and its fiscal 2018 budget request is lower still.The $624 million sought in 2018 is sufficient to launch the first X-plane, the Quiet Supersonic Technology (QueSST) low-boom flight demonstrator planned to fly in 2021. But under current plans the first of a series of Ultra-Efficient Subsonic Technology (UEST) X-planes will not follow it into the skies before 2026.
The agency is taking a similar approach to the first subsonic X-plane, having begun with contracts to define system requirements for five different configurations. Under current plans, a draft request for proposals (RFP) for the “UEST1” X-plane is to be released in fiscal 2018, says Fay Collier, IASP associate director for flight strategy.The final RFP is to follow in fiscal 2019, with the intent to competitively select two concepts to take through to preliminary design reviews. One configuration will then be selected for the X-plane. First flight is planned for fiscal 2026, but “we are looking at ways to bring that to the left a bit, somewhere between fiscal 2024 and 2026,” Collier says. A second “UEST2” X-plane would follow five years later.
The slowing of the X-plane initiative highlights a growing tension between the pace with which industry is evolving and the speed at which NASA can respond. The agency is looking at how it can support the emerging urban air mobility market, and the earliest it could have a dedicated program in place is fiscal 2021, says Jaiwon Shin, associate administrator for aeronautics. This contrasts with Uber’s ambitious plans for experimental flights in 2020 and commercial service by 2023.
A series of wind tunnel tests revealed the unusual engine inlet positioning for NASA’s supersonic X-plane meets the performance goals for the Lockheed Martin-designed aircraft, a NASA Glenn Research Center aeronautics engineer says.
A series of wind tunnel tests revealed the unusual engine inlet positioning for NASA’s supersonic X-plane meets the performance goals for the Lockheed Martin-designed aircraft, a NASA Glenn Research Center aeronautics engineer says.The quiet supersonic transport (QueSST) X-plane demonstrator will begin a series of flight tests in 2020 with an inlet placed atop the fuselage and behind the cockpit, a rare configuration for a supersonic aircraft not seen since early 1950s designs, such as the Douglas X-3 Stiletto and Convair F2Y Sea Dart.The unusual engine placement is driven by the purpose of the QueSST demonstrator, explains Ray Castner, a NASA Glenn engineer, speaking at the Experimental Aircraft Association’s annual event in Oshkosh, Wisconsin on 25 July.
“Most supersonic aircraft have the engines near the front on the nose or underneath in the clean air flow,” Castner says. “We now have our engine up top and that’s for boom-shielding. That way, the disturbance from the engine goes up, and does not propagate down to the ground and contributes to boom signature.”NASA’s Glenn Research Center in Cleveland, Ohio, performed 73h of testing of a model of the X-plane in the facililty’s 8ft X 6ft wind tunnel, the first such laboratory tests of such an engine inlet position for a supersonic aircraft of which the agency is aware.The result satisfied NASA’s engineers that the X-plane’s unique inlet position will work.“This inlet is actually more efficient than I thought it would be,” Castner says. “It was about 96-98% efficient, so that’s pretty good.”
Although the positioning was different, the nature of the NASA’s QueSST demonstration allowed Lockheed to use a relatively simple inlet design. NASA plans to have the aircraft take-off, make two passes over a city at Mach 1.4, then land. The design includes a diverterless bump to steer boundary layer airflow away from the inlet, but requires no moving pieces required for supersonic aircraft designed to cruise at higher speeds.“It’s a [sonic] boom demonstrator. It’s not an inlet demonstrator. There is a higher performing inlet that we could have chosen, but a lot of those inlets have moveable parts,” Castner says.NASA’s concerns about boundary layer flow over the top of the fuselage with the inlet’s placement drove other design decisions, he adds. After Lockheed completed the preliminary design, NASA released an image of the demonstrator with six vortex generators set between the cockpit canopy and the engine inlet. Lockheed placed the vortex generators there to energise the boundary layer flow and prevent the inlet from ingesting that relatively stagnant air, he says.
Residents along Florida’s Space Coast will soon hear a familiar sound — sonic booms. But instead of announcing a spacecraft’s return from space, they may herald a new era in faster air travel.NASA’s Kennedy Space Center in Florida is partnering with the agency’s Armstrong Flight Research Center in California, Langley Research Center in Virginia, and Space Florida for a program called Sonic Booms in Atmospheric Turbulence, or SonicBAT II. Starting in mid-August, NASA F-18 jets will take off from the Shuttle Landing Facility (SLF) and fly at supersonic speeds while agency researchers on the ground measure the effects of low-altitude turbulence on sonic booms.
According to John Graves of NASA Flight Operations in Kennedy’s Spaceport Integration and Services, for projects such as SonicBAT, NASA coordinates with Space Florida who manages the facility’s schedule.“Working with representatives from the Armstrong center, we go through Space Florida to request use of the runway,” he said. “It’s an arrangement that works very well.”The F-18 will begin flights on Aug. 21, flying two to four times a day over a period of ten days. But the actual test window may be two weeks to allow for weather and other possible delays.Graves explains that SonicBAT is an unusual test in that it uses a typical military aircraft with its loud sonic boom to help engineers better understand the sounds from future quiet supersonic aircraft“We’re hoping we can eventually lower sonic booms to a low rumble,” he said. “The goal is to eventually accommodate jets that can fly from New York to Los Angeles in two hours.”Armstrong started SonicBAT investigations at Edwards Air Force Base last year. This will be the second round of tests.“Edwards is a hot, dry environment,” he said. “The team at the Armstrong center wants to now try to collect similar data in the hot, humid climate we have here.”
Interesting discussion, but I am a little confused. Why are they saying this is the first time an above the fuselage supersonic inlet has been tested. Does the Mach 2 capable F-107 not count?
Lightweight megawatt-scale drive systems are essential if electric propulsion is ever to succeed in commercial aircraft. Systems much more powerful than those in cars and far lighter than in ships are required. NASA has launched research into electric motors and power converters at the megawatt level, as these could support the near- or medium-term development of partially turboelectric and hybrid-electric propulsion systems for aircraft up to single-aisle airliner size. Hardware is already ...