Lockheed Martin X-59 Quesst

A model in a wind tunnel at NASA Langley, September 2017

In February 2016, Lockheed Martin was awarded a preliminary design contract, aiming to fly in the 2020 timeframe.[2] A 9% scale model was to be wind tunnel tested from Mach 0.3 to Mach 1.6 between February and April 2017.[3] The preliminary design review was to be completed by June 2017.[4] While NASA received three inquiries for its August 2017 request for proposals, Lockheed was the sole bidder.[5]

On April 2, 2018, NASA awarded Lockheed Martin a $247.5 million contract to design, build and deliver in late 2021 the Low-Boom X-plane. On June 26, 2018, the US Air Force informed NASA it had assigned the X-59 QueSST designation to the demonstrator.[6] By October, NASA Langley had completed three weeks of wind tunnel testing of an 8%-scale model, with high AOAs up to 50° and 88° at very low speed, up from 13° in previous tunnel campaigns.[7] Testing was for static stability and control, dynamic forced oscillations, and laser flow visualization, expanding on previous experimental and computational predictions.[8]

From November 5, 2018, NASA was to begin tests over two weeks to gather feedback: up to eight thumps a day at different locations to be monitored by 20 noise sensors and described by 400 residents, receiving a $25 per week compensation. To simulate the thump, an F/A-18 Hornet is diving from 50,000 ft (15,200 m) to briefly go supersonic for reduced shock waves over Galveston, Texas, an island, and a stronger boom over water.[9] By then, Lockheed Martin had begun machining the first part in Palmdale, California.[10]

In May 2019, the initial major structural parts were loaded in the tooling assembly.[11] In June, assembly was getting underway.[12] The external vision system (XVS) was flight tested on a King Air at NASA Langley.[13] This will be followed by high speed wind tunnel tests to verify inlet performance predictions with a 9.5%-scale model at NASA Glenn Research Center. The critical design review was successfully held on September 9–13, before the IRB report to NASA's Integrated Aviation Systems Program by November.[14] Then, 80–90% of the drawings should be released to engineering.[11] The wing assembly was to be completed in 2020.[12] In December 2020, construction was halfway completed, and first flight was then planned for 2022.[15]

After flight-clearance testing at the Armstrong Flight Research Center, an acoustic validation will include air-to-air Schlieren imaging backlit by the Sun to confirm the shockwave pattern until September 2022.[5] NASA will conduct flight tests over U.S. cities to verify the safety and performance of the X-59's quiet supersonic technologies and evaluate community responses for regulators, which could enable commercial supersonic travel over land.[16]

Community-response flight tests starting in 2023–2025 will be used for ICAO's Committee on Aviation Environmental Protection meeting (CAEP13) establishing a sonic boom standard.[5] The results of the community overflights will be delivered to the ICAO and the FAA in 2027, allowing for a decision to be made to revise the rules on commercial supersonic travel over land in 2028.[17]

NASA reported the installation of the General Electric F-414-GE-100 engine on the X-59, which took place at Lockheed Martin's Skunk Works in Palmdale, California early November 2022. The engine is 13 feet (4.0 m) long and produces 22,000 pounds-force (98 kN) of thrust.[18] As of November 2022 the X-59's first flight is planned for 2023.[19]

X-59 characteristics

The Low-Boom X-plane will be 94 ft (29 m) long with a 29.5 ft (9.0 m) wingspan for a maximum takeoff weight of 32,300 lb (14,700 kg). Propelled by a General Electric F414 engine, it should reach a maximum speed of Mach 1.5 or 990 mph (1,590 km/h), and cruise at Mach 1.42 or 940 mph (1,510 km/h) at 55,000 ft (16,800 m).[20] The cockpit, ejection seat and canopy come from a Northrop T-38 and the landing gear from an F-16.[5] With afterburner, its engine will provide 22,000 lbf (98 kN) of thrust.[21]

The ground noise is expected to be around 60 dB(A), about 1/1000 as loud as current supersonic aircraft. This is achieved by using a long, narrow airframe and canards to keep the shock waves from coalescing.[4] It should create a 75 Perceived Level decibel (PLdB) thump on ground, as loud as closing a car door, compared with 105-110 PLdB for the Concorde.[5] The central engine has a top-mounted intake for low boom, but inlet flow distortion due to vortices is a concern.[11]

The flush cockpit means that the long and pointed nose-cone will obstruct all forward vision. The X-59 will use an enhanced flight vision system (EVS), consisting of a forward 4K camera with a 33° by 19° angle of view, which will compensate for the lack of forward visibility.[5][22]

United Technologies subsidiary Collins Aerospace was selected to supply its Pro Line Fusion Cockpit avionics, displaying the boom on the ground, and EVS with long-wave infrared sensors.[23] The Collins EVS-3600 multispectral imaging system, beneath the nose, is used for landing, while the NASA external vision system (XVS), in front of the cockpit, is giving a forward view.[11]

Lockheed Martin released a video showing an assembled X-59 rolling out of a hangar on August 4, 2023.[24]

• Quiet Spike
• Gulfstream X-54
• Shaped Sonic Boom Demonstration

Related lists

• List of X-planes

Wikimedia Commons has media related to Lockheed Martin X-59 QueSST.

• "Quiet Supersonic Technology X-Plane". Lockheed Martin. September 2, 2021.
• "Low-Boom Flight Demonstration". NASA. February 15, 2018.
• "How X-planes may solve the sonic boom problem". BBC. March 27, 2023.