BOOM OR BUST
PLANE MAKERS COURT CONCORDE’S SPEEDS, BUT FIGURES MAY NOT STACK UP IN NEW WORLD OF VIRTUAL MEETINGS
VIRTUAL COMMUNICATIONS DON’T ALLOW FOR THOSE SPONTANEOUS AND OFTEN LUCRATIVE CONNECTIONS MADE AT THE HOTEL BAR AFTER A CONFERENCE OR IN THE COFFEE BREAK. — BEVERLEY FEARIS
It is almost 20 years since Concorde’s last flight and the end of supersonic air travel that cut flight times between London and New york to just three hours — for those with deep enough pockets.
Now a handful of companies are working on passenger aircraft capable of breaking the Mach 1 sound barrier of 700 m.p.h., potentially ushering in a new age of highspeed travel.
Startups such as Aerion, Boom Supersonic and Spike Aerospace have either attracted hundreds of millions in funding or billionaire backers. Business jet makers and Virgin Galactic are also thought to be mulling projects. Some companies have attracted support from industry heavyweights such as Boeing, General Electric and rolls-royce.
“Concorde was a marvel of technology,” says Simon Carlisle, director of strategy at rolls-royce. “The physics haven’t changed. We just need smarter ways of solving the problems supersonic flight presents.”
Even before tackling the technical issues, companies need to consider whether there will be the demand for supersonic travel. Air travel has dwindled because of coronavirus and the world has learned to hold meetings virtually rather than face to face. Even when the pandemic is over, will we need to fly for work at all, let alone supersonically?
“Zoom and Teams might work for internal meetings, and perhaps for existing clients, but in-person meetings are vital for making new connections,” says Beverley Fearis, editor of Business Traveller Magazine.
She points to Bill Gates’s prediction of a 50 per cent drop in business travel as a consequence of the pandemic, but also highlights the little-reported kicker to the Microsoft boss’s forecast.
“He’s admitted he’s made no new friends or business connections during the pandemic,” says Fearis. “Virtual communications don’t allow for those spontaneous and often lucrative connections made at the hotel bar after a conference or in the coffee break.”
While commercial air travel has been hammered by COVID-19, private jets have been less affected.
Fearis adds: “Many travel management companies say their most elite, wealthy clients have continued to travel. For these people, travel is integral to their lifestyle — they’ll have multiple homes and will be used to regularly flying across time zones. That can’t be replaced by Zoom. These are the types of people who would be willing and able to pay for supersonic travel — the very elite.”
A UBS survey indicates 20 per cent of passengers would be willing to pay at least 50 per cent more for air travel if flight times could be cut in half. The bank calculates this means the market for supersonic flight could be worth us$160 billion by 2040.
What, then, are the challenges? Perhaps the most pressing is fuel. Travelling faster than the speed of sound burns five to seven times more fuel per passenger than on a subsonic aircraft, according to the International Council on Clean Transportation, which also estimates limits for nitrogen oxides and carbon dioxide emissions will be exceeded by 40 per cent and 70 per cent, respectively.
However, engine technology is advancing along with new materials, meaning less fuel will be needed, and aircraft will be lighter, again reducing consumption.
“For supersonic flight to be investable, it has to be viable. That’s still to be proven,” says Carlisle.
New engines won’t be as fuel thirsty or polluting as those powering Concorde, and sustainable aviation fuel made from sources such as waste oil and biological materials “could help bridge the gap,” the rolls executive adds.
Another environmental issue is noise. Breaking the sound barrier results in a sonic boom, which sounds similar to a thunderclap when heard on the ground. But it’s not a one-off: the shock wave follows the aircraft all along its flight path while it is travelling faster than the speed of sound. It’s unlikely, therefore, that supersonic flight will ever be allowed over land. For many routes, this negates the attraction.
Transatlantic and transpacific routes could be the most feasible. Aerion, Boom and Spike have all said their aircraft are intended to have ranges of about 4,500 miles or more, covering flights from Europe to America’s East Coast, and the West Coast to Japan. Longer flights between the West Coast and South East Asia and China could be more of a challenge.
Computer design, new materials and manufacturing processes can also reduce the volume of a sonic boom or even redirect it. In 2016, Nasa and Lockheed Martin built the X-59 QUESST Quiet Supersonic Technology aircraft. When flying at 55,000 feet, it produces a sonic boom of 75 PLDB (perceived level decibel) at ground level. This is the equivalent of a car door slamming. In comparison, Concorde’s sonic boom was 105 PLDB, which sounded like a small explosion.
Although new materials may solve some problems, they may encounter new ones such as how they react to the enormous temperatures air friction causes in high-speed flight. Concorde expanded almost a foot as it heated up while cruising at Mach 2, and thermal properties of new materials will need to be thoroughly researched.
How a new generation of faster aircraft mix with the existing fleet could also cause headaches. While supersonic aircraft will probably cruise at 10,000 feet or more above subsonic aircraft as they are able to power through the thinner atmosphere, they may have faster takeoff and landing speeds, causing issues with integrating them into flight plans around airports.
Carlisle says investigating the possibilities is worthwhile, explaining how rolls is learning from the startups with which it is working. And he warns against ignoring what may appear to be just a dream.
“you ignore these innovative ideas at your peril,” says Carlisle. “There’s a parallel with Spacex. It was unencumbered by history. Look what it’s achieved.”