NASA lowers the boom for supersonic travel

April 05, 2018
NASA lowers boom in supersonic travel
A rendering of the X-plane on the ground at Palmdale. Image: NASA.

NASA is hoping to overcome one of the big handicaps to supersonic travel in an uber-cool supersonic “X-plane” that announces its prowess with more of a thump than a bang.

The US space agency has awarded a $US247.5 million contract to Lockheed Martin to build from scratch a needle-nosed aircraft that could happily grace any chapter of the Star Wars franchise.

The 94-foot long plane is expected to start test flights in 2021 and fly at a cruising altitude of 55,000ft at Mach 1.42, or 940mph (1512kmh), with a top speed of Mach 1.5.

But it will use the latest in supersonic technologies to reduce the window-shaking sonic boom to a thump equivalent to the noise of car door closing.

NASA sonic boom lower X-plane
Quieter times: a comparison of the X-Plane’s thump with an F-18’s sonic boom. Source; NASA.

NASA says the plane’s mission is to provide data it hopes will allow the design of airliners capable of flying across land at supersonic speeds, a practice banned by the US Federal Aviation Administration more than four decades ago.

The single-pilot X plane will be propelled by a General Electric F414 engine used by F/A-18 fighters. A single pilot will be in a cockpit based on the design of the rear seat of the T-38 training jet famously used for years by NASA astronauts.

A tentative schedule sees a critical design configuration review in 2019 that, if successful,  leads to the construction of the aircraft at Lockheed Martin’s Skunk Works facility in Palmdale, California,  and delivery to NASA’s Armstrong Flight Research Center in 2021.

A second phase beginning 2022 will see NASA fly the plane at the supersonic test range in Edwards to prove the quiet supersonic technology works as expected and the plane is safe.

A series of trials will be conducted between 2022 and 2025 over four to six US cities to gauge community response to the technology.

NASA says key to success for the Low-Boom Flight Demonstrator will be sonic booms “so quiet, people on the ground will hardly notice them if they hear them at all”.

It plans to deliver the data to the  Federal Aviation Administration (FAA) and the International Civil Aviation Organization (ICAO) in 2025 so they can develop and adopt new rules to allow commercial supersonic flight over land.

X-Plane supersonic boom
Source: NASA.

The agency says the key to the X-plane’s design is the way its uniquely-shaped hull generates shockwaves.

In conventional aircraft, the shockwaves coalesce as they expand away from the aircraft’s nose and tail, resulting in two distinct and thunderous sonic booms.

The X-plane’s design prevents this from happening by directing them away from the aircraft so that reach the ground much weaker and still separated.

NASA has been looking at the idea since it was first theorized in the 1960s and tested it successfully in 2003-04 on an F-5E fighter with a modified nose.

Its confidence was further bolstered by more recent wind-tunnel testing, advanced computer simulation tools and actual flight testing.

“We’ve reached this important milestone only because of the work NASA has led with its many partners from other government agencies, the aerospace industry and forward-thinking academic institutions everywhere,” said Peter Coen, NASA’s Commercial Supersonic Technology project manager.

NASA is not the only organization looking at supersonic flight.

Japan Airlines and Virgin Atlantic are among the airlines supporting a push by US-based Boom Supersonic Technologies to develop a 55-passenger supersonic aircraft capable of flying a Mach 2.2.

Japan Airlines Boom supersonic aircraft

JAL late in 2017  committed to taking 20 of the aircraft and backed the company with a $10 million strategic investment.

The full sized plane will be 10 percent faster than Concorde and is expected to carry passengers at fares that are 75 percent lower and be 30 percent quieter.

But it will still produce a sonic boom and is expected to stick to Oceanic routes.

READ boom times in the race for a supersonic airliner.

A smaller two-seater XB-1 demonstrator aircraft, dubbed “Baby Boom”, is expected to fly at the end of 2018.

Even Boeing, whose 1960s-era 2707 supersonic transport proved to be a white elephant, is having another look at faster than sound options.

Read the supersonic airliner that turned into a white elephant.

Boeing vice president product development Mike Sinnett referred to the Seattle manufacturer’s research on the next SST (supersonic transport) during a presentation about future projects at 2017’s  Paris Air Show.

“We are working on an SST with lower boom technology, it’s exciting work but still very challenging, as it is difficult environmentally and as a business case,”  Sinnett said at the time.

The Boeing executive said his company was reviewing designs “from business jet size to passenger jets of some 70 seats”

“We will see it sooner than in 20 years’ time, but it might not be us doing it in this time period,’’ he said.