Will supersonic jets return with a boom?

According to Boeing, it has made “a significant investment” in US start-up Aerion to accelerate technology development and aircraft design, with the goal to bring Aerion’s AS2 supersonic business jet to market.

Joining Boeing is GE Aviation, who will supply the AS2 with an advanced Affinity engine, the initial design phase for which was completed last year. The aircraft is designed to fly at 1,000mph and is slated for its first flight in 2023.

Sameer Savani, head of innovation and engineering at Aerospace, Defence, Security & Space trade association (ADS), said to The Manufacturer, “There are challenges to overcome before supersonic aircraft can be commercially viable around the world, both with emissions and the economics. In economic terms, supersonic jets are a global market opportunity, with some estimates predicting 1,300 aircraft worth £193bn over a ten-year period to be operational.”

What is supersonic speed?

Supersonic speed is a rate of travel of an object that exceeds the speed of sound (Mach 1). 

Concorde: Supersonic in history

British Airways’ Concorde made just under 50,000 flights and flew more than 2.5 million passengers supersonically over 27 years, according to BA.

With a take off speed of 250mph and a cruising speed of 1,350mph – more than twice the speed of sound – a typical journey from London to New York would take a little less than three and a half hours, as opposed to eight hours for a regular flight.

However in 2003, British Airways withdrew Concorde, ending the world’s only supersonic passenger service due to rising costs and declining demand.

Savani commented: “The principal historic example – Concorde – did not achieve long-term financial viability, but companies exploring the potential of supersonic aircraft believe they can deliver a sustainable business model, at roughly business class ticket prices, and have secured significant investment.”

SSC could return… without a ‘boom’

A sonic boom is a thunder-like noise heard when an aircraft flies overhead at supersonic speed. As an aircraft travels through the air at this speed, molecules are pushed aside with great force and this forms a shock wave. The bigger and heavier the aircraft, the more air it displaces.

There are several factors that can influence sonic booms; weight, size, and shape of the aircraft or vehicle, its altitude and flight path, and weather or atmospheric conditions. Current legislation bans commercial supersonic aircraft from operating over land.

Savani says, “Potentially the biggest issue for developing new supersonic aircraft is noise and the lack of internationally approved environmental regulatory standards, which would be created by the International Civil Aviation Organisation (ICAO).”

“Noise standards today are much stricter than when Concorde first flew, and the engines that can propel an aircraft at supersonic speeds are louder than those used by conventional civil aircraft.”

Last year, NASA awarded Lockheed Martin a £193m contract to develop an aircraft capable of reaching supersonic speed without creating the ‘boom’. In November, the defence giant announced its experimental supersonic X-plane had entered production.

GE will power the X-plane with a GE F414-100 engine that uses a slender fuselage. According to GE, this will produce several small shock waves that are reportedly eight times quieter than a sonic boom.

Increasing environmental concern

Concerns regarding the environment have been raised, as faster planes could emit more polluting carbon into the atmosphere. “They are also likely to generate greater emissions, creating a challenge for both manufacturers and regulators to overcome before new supersonic civil aircraft can be regularly seen in the skies,” Savani says.

This also at a time when the focus on sustainable travel is rising rapidly. Earlier this year Rolls-Royce revealed plans to build a zero-emissions plane, which it expects to hit target speed of over 300mph.

Scheduled for flight next year, the electric aircraft could be the fastest all-electric plane in history. The current record set by Siemens in 2017 is 210mph.

Though he concludes, “Aerospace is an innovative industry and is continually seeking to achieve technological advances that deliver a better experience for customers, as well as delivering cleaner, more fuel efficient air travel. UK industry is primed to contribute to the development of supersonic aircraft, including through the expertise our aerospace sector offers in propulsion systems.”

The question remains: do we need supersonic travel? If the answer is yes, is there a way to dampen the impacts of the sonic boom, and also make aircrafts economically and environmentally viable? As aerospace giants and start-ups scramble to be the first supersonic aircraft to follow Concorde, can they bring supersonic back, with or without a boom?