NASA's incredible supersonic X-plane is cleared for final assembly ahead of testing in 2021

NASA‘s incredible X-plane that is shaped to muffle the sound of its sonic boom has been cleared for assembly by a management review ahead of test flights in 2021.

Dubbed the ‘son of Concorde’ after the Mach 2 airliner, the X-59 Quiet SuperSonic Technology (QueSST) is NASA’s first large experimental plane in three decades.

The X-59 will cruise at Mach 1.4 (925 mph/1,488 km/h) and is designed for supersonic flight while preventing its sonic boom from being heard on the ground.

If successful, the craft could one day travel from London to New York in just over three hours, while transcending objections to supersonic air travel over land.

The unusual design also features no front-facing cockpit window — instead, cameras will feed the forward view to a 4K ultra-high-resolution monitor in the cockpit.

Construction of the X-59 — to a $247.5 million (£187.5 million) contract — is being undertaken by Lockheed Martin Aeronautics at their Palmdale, California factory.

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NASA’s incredible X-plane that is shaped to muffle the sound of its sonic boom has been cleared for assembly by a management review ahead of test flights in 2021

Passing the ‘Key Decision Point-D’ management review — which was held at NASA’s Washington headquarters on December 12, 2019 — was the last administrative hurdle for the X-59 QueSST’s project to leap.

‘With the completion of the Key Decision Point-D we’ve shown the project is on schedule, it’s well planned and on track’ said Bob Pearce NASA’s associate administrator for aeronautics.

‘We have everything in place to continue this historic research mission for the nation’s air-travelling public.’

At Lockheed Martin’s so-called ‘Skunk Works’ factory in California, three major work areas have been set up for the construction of the X-59.

These include assembly sections for the craft’s main fuselage, its wing and the ’empennage’ — or tail assembly.

It is expected that the final assembly of the X-59 and the integration of its on board systems will be completed late in 2020.

At this point, NASA officials will meet to approve the craft’s first flight in 2021.

At Lockheed Martin’s so-called ‘Skunk Works’ factory in California, pictured, three major work areas have been set up for the construction of the X-59. These include assembly sections for the craft’s main fuselage, its wing and the ’empennage’ — or tail assembly

WHAT IS NASA’S ‘SON OF CONCORDE’ X-PLANE?

Nasa is developing a 1,100mph (1,770kph) aircraft that has been dubbed the ‘son of Concorde’.

The vehicle is the first in a series of aircraft Nasa is developing with Lockheed Martin in a quest to build a commercially viable supersonic jet.

It is designed to fly at Mach 1.4 (925 mph / 1,488 kph) at an altitude of 55,000 feet (10 miles).

Dubbed the X-59 Quiet Supersonic Transport (QueSST), the research craft aims to cut out the sonic booms associated with supersonic travel.

Pictured is an artist’s impression of the Quiet Supersonic Transport (QueSST) low-boom flight demonstrator (LBFD)

The aircraft is shaped to separate the shocks and expansions associated with supersonic flight to reduce the volume of the shaped signature, and was developed by Lockheed’s Skunk Works over 20 years.

The team is hoping to achieve a sonic boom 60 dBA lower than other supersonic aircraft, such as Concorde.

Recent research has shown it is possible for a supersonic airplane to be shaped in such a way that the shock waves it forms when flying faster than the speed of sound can generate a sound at ground level so quiet it will hardly will be noticed by the public, if at all.

Dubbed the ‘son of Concorde’ after the famous Mach 2 airliner — pictured here being escorted by the Royal Air Force’s ‘Red Arrows’ Aerobatic Team in 2002 — the X-59 Quiet SuperSonic Technology (QueSST) is NASA’s first large experimental plane in three decades

 The unusual design of the X-59 features no front-facing cockpit window — instead, cameras will feed the forward view to a 4K ultra-high-resolution monitor in the cockpit

The X-59 will cruise at Mach 1.4 (925 mph/1,489 km/h) and is designed for supersonic flight while preventing its sonic boom from being heard on the ground

The X-59 QueSST is part of NASA’s so-called Low Boom Flight Demonstrator project, which aims to achieve supersonic flight while creating a sonic boom that can barely be heard at ground level.

In fact, the ground noise level from the X-59 is expected to only reach around 75 Perceived Level decibels (PLdB) and sound like a car door being closed — the Concorde, for comparison, produced a 105-110 PLdB noise at ground level.

This improvement will be achieved through a long, narrow airframe and canards — small forewings — to prevent shockwaves from coalescing 

It is this design that necessitates the lack of a front-facing window — and the compensatory ‘enhanced flight vision system’ of cameras and a cockpit monitor screen — as the pointed nosecone will obstruct the view.

 If successful, the craft could one day travel from London to New York in just three hours, while transcending objections to supersonic air travel over land

HOW WILL NASA REDUCE THE SOUND OF SONIC BOOMS?

In a conventional supersonic aircraft, shockwaves from the nose, cockpit, inlets, wings and other features come together as they move through the atmosphere into strong shocks emanating from the nose and tail.

These are known as bow and tail shocks, respectively.

As these shockwaves pass over the ground, air pressure rises sharply, declines, then rises rapidly again.

It’s this that produces the classic ‘double-bang’ sonic boom.

In a conventional supersonic aircraft, shockwaves from the nose, cockpit, inlets, wings and other features come together as they move through the atmosphere into strong shocks emanating from the nose and tail

Reshaping the aircraft to produce a longer, more slender shape is the best way to generate shockwaves of lower, more equal strength that do not form into such strong bow and tail shocks.

Nasa and other organisations are working on creating shapes to reduce sonic booms. 

Stretching the nose to break the bow shock into a series of weaker shockwaves is particularly effective.

This lowers and spreads that initial pressure peak and softens the first bang of the sonic boom.