Supersonic hopes

CONCORDE REMAINS the most vivid symbol of technical progress in the commercial aircraft industry. How can it not be? It let people in everyday clothes fly at a speed faster than a rifle bullet, taking them high into the stratosphere and aff ording them a view of the curvature of the Earth.

Lockheed Martin has unveiled its Quiet Supersonic Technology Airliner concept.
Lockheed Martin

The early dream that Concorde represented the future for commercial aviation was just that, illusory, with the jet ending up as a highly niche aircraft used mainly by moneyed and/or timesensitive passengers who could aff ord to fly it. The aircraft still became a pop culture icon, of course, which added gloss to its glamorous image.

Nearly 16 years after Concorde last flew – a curious moment given how an aircraft that still looked futuristic became a museum piece – there are still some years yet before supersonic passenger air travel is a reality again, but there are eff orts to make it happen.

In June, Lockheed Martin unveiled its Quiet Supersonic Technology Airliner (QSTA) concept with a relative lack of fanfare; it was announced at the American Institute of Aeronautics and Astronautics Aviation Forum in Washington, DC, and not at the Paris Air Show, this year’s biggest aerospace event, which began on the same day.

Lockheed Martin told AIR International: “QSTA continues more than two decades of experience advancing quiet supersonic technologies. [It] is a conceptual design and the result of a study completed to understand what a passenger-carrying aircraft leveraging quiet supersonic technologies could look like.”

The company’s CGI rendering of the QSTA concept shows a striking planform with sharply swept-back delta wings and twin tails. The QSTA would be equipped with two 40,000lb-thrust (177kN) engines and seat 40 passengers, according to a Lockheed Martin slide on the aircraft’s configuration.

The jet would be 225ft (68m) in length and have a 78ft (23m) wingspan, making it roughly the same length as the Boeing 787-10, the largest 787 Dreamliner variant, and about as wide as a smaller regional jet. Wing area would be 3,000ft2 (279m2) and gross weight 210,000lb (95,254kg).

The QSTA work is a separate eff ort from Lockheed Martin’s work with NASA on the X-59 QuESST (Quiet Supersonic Transport) demonstrator, built for the Low- Boom Flight Demonstration mission that will see the aircraft fly over communities in the United States to gather data about quiet supersonic flights. The X-59 will fly in 2022.

In June NASA announced the X-59 will not have a forward-facing cockpit window. Instead, a 4K monitor will provide the central forward view showing the pilot stitched images from two external cameras which, combined with terrain data from an advanced computing system, will provide what NASA calls an eXternal Visibility System or XVS. Displays beneath the XVS will provide aircraft systems and trajectory data. Two portals on the fuselage and the traditional canopy will enable the pilot to see the horizon.

The XVS is designed, NASA explained, to help ensure the X-59’s design shape reduces a sonic boom. The data collected during the X-59 test flights will be presented to the US Federal Aviation Administration, enabling the regulator to make an informed decision on whether to scrap the current regulations banning commercial supersonic flight over land, which torpedoed the commercial hopes for Concorde back in the 1970s.

Lockheed Martin said: “Overturning this ban [creates] the opportunity for an entire new industry. With the ability to fly anywhere in the world in half the time it takes today, there is a tremendous amount of market potential for aircraft manufacturers.”

This potential explains why other companies are planning aircraft they hope will one day open a new age of supersonic passenger air travel. Aerion Supersonic and Spike Aerospace are developing supersonic business jets, while Denver, Colorado-based Boom Supersonic is planning a supersonic airliner called Overture.

Boom is developing a demonstrator called the XB-1 that will generate data to support the development of aerodynamics, stability, control and handling qualities, the propulsion inlet, nozzle and control systems for Overture.

Boom gave an update about its work at the Paris Air Show. Its plans are delayed. Having earlier announced its intention to fly the XB-1 in 2019, only rollout is planned by the end of this year, with flight tests now planned for 2020.

A 4K monitor showing a view of the world outside will serve as the central forward view on the X-59 QuESST demonstrator.

However, Boom says there has been progress. The company said supersonic inlet wind tunnel tests demonstrated performance to reach the targeted Mach 2.2 flight speed is achievable and that the XB-1 “exceeded the performance of Concorde’s inlets”.

Full range flight telemetry system tests proved a two-way data link for XB-1 and spin tunnel testing has been carried out to understand the departure modes of the aircraft, as well as what the company called “fully comprehensive aero database generation” simulating aerodynamic flow.

Boom also announced other companies will provide specialist input into its project. Dassault Systèmes will use its 3DEXPERIENCE software to accelerate the design process, JPA Design will design the interior and Stratasys will supply 3D-printed polymer-based parts.

Mark Broadbent