Guy Leitch – Aviation has a fascinating ability to suck people, who should know better, into investing in fundamentally absurd ideas.

Guy Leitch.

LEAVING ASIDE THE ONGOING delusion of flying cars, the two absurdities that continue to grip people’s imagination are the notions that: Firstly, supersonic airliners will be with us before 2030. Secondly: that battery powered multirotor vertical takeoff air taxies will be practical even earlier than 2030.

It was the rise of computer assisted design (CAD) that has driven many of these more unlikely flights of fancy. All you need is a PC and a gifted graphic designer and a great website (see https:// boomsupersonic.com/) – and you have an aircraft design that will draw gasps of admiration and, if you have the right connections, suck in some government funding.

In South Africa we have the preposterous idea punted by, of all things, a plastic surgeon; Dr Reza Mia, of a vertical takeoff and landing business jet, called the Pegasus. Mia is determined to persuade others that his still etherware design can defy basic economic principles – and gravity.

‘All you need is a PC and a gifted graphic designer’

In my view – if he ever managed to succeed in getting the billions of dollars of funding required to certify such an aircraft – it would never recoup its investment as it would still be a crap bizjet with, thanks to the weight and drag of the fans in the wings, terrible speed, range and payload – which are after all, key requirements for a successful bizjet.

Leaving aside for another article the inherent risks and compromises of VTOL, the focus of my incredulity this month is Supersonic Transports (SSTs).

United has put down US10m non-refundable deposits on the Boom Overture.

Perhaps because the Concorde actually achieved supersonic passenger flight 50 years ago, people retain an enduring belief that SSTs are feasible.

Was the Concorde a success? In the end only British Airways and Air France operated it. High costs and concerns about noise limited its scheduled use to expensive flights across the Atlantic. The fatal crash in 2000 at Paris and the travel slump after 9/11 finally killed it off. And before the Concorde there was the Russian Tupolev 144D. Two fatal

crashes, one in 1973 at the Paris Air Show and another in Russia in 1978, ended that government funded vanity.

Unlike the Concorde, which was funded by the British and French governments, the private sector will have to fund the development of the next SST. So hard-nosed investors will ask – can the huge development costs of a new SST ever provide a return on investment – and especially a return large enough to cover the risks?

The consensus is that quite simply there isn’t enough money available from those who actually know what it takes to build an SST, get it certified and into the market with enough sales to recover the initial investment.

Yet, in the face of this scepticism, United Airlines announced in the middle of August that they had paid a non-refundable deposit of U$10 million to buy Boom Overture jets.

The Overture is less ambitious, smaller and slower than Concorde. It is designed to carry 65 to 80 passengers at Mach 1.7 over water, about twice as fast as commercial jets. Boom currently has 130 orders for its Overture, compared with just the 14 Concordes that entered service. So for those, like me who wish passenger jets could go faster, there is hope. I confess to all the aviation nuts out there that I hate being cooped up in an aluminium tube with hundreds of other irritable, stale and sweaty passengers on long haul daylight flights.

The Concorde first flew 53 years ago, yet still cannot be replicated.

Boom has said it expects its first Overture to roll off the production line in 2025 and to carry passengers by 2029.

But like the Pegasus, I fear it’s all just a massive public relations stunt. Even with 130 orders, the hard reality of economics is inescapable. For Boeing or Airbus to certify a conventional new subsonic airliner requires at least a U$35 billion investment. To develop, test and certify an all-new supersonic airliner will be a multiple more expensive.

The challenges are immense. New SST designs have tiny cramped fuselages and look unbelievably futuristic because of the need to attenuate sonic booms. Then there is the noise of the engines on takeoff with afterburners roaring, the appalling fuel inefficiency, and the need to be able to safely operate as high as FL600, all of which make the costs insurmountable.

‘Why is it so difficult to replicate the Concorde?’

It will require mountains of cash. One of my favourite aviation analysts is Richard Aboulafia who earlier this year said when discussing SSTs; “The only thing that matters is cash and so far, it isn’t there.”

Why is it so expensive to build a new modern SST? What are the obstacles that make it so difficult to replicate the Concorde?

The big one is still the sonic boom. Then there is the appalling fuel consumption and associated carbon emissions. Weight is everything, and so a limited passenger-carrying capacity and cramped cabin could make it difficult to sell enough tickets to make SST flights profitable. Finally, there is the challenge for certification using standards that do not yet exist, from dozens of governments.

The environment is another big challenge – and one the Concorde did not have to deal with. The proponents claim modern SSTs will do what the Concorde did not—meet global fuel-efficiency standards. However, environmental scientists Anastasia Kharina and Tim MacDonald, of the International Council on Clean Transportation reckon that, “Commercial SSTs could be three times as fuel intensive per passenger as comparable subsonic aircraft.”

To assuage the greenies, Boom says it will use biofuels like sustainable aviation fuel, as does California’s Exosonic, with its proposed 70-passenger jetliner.

Boston-based Spike Aerospace is focusing on an 18-passenger business jet with a proprietary technology it claims will keep the sonic boom at the level of vacuum cleaner. It recently received FAA approval for limited testing of its design over land.

Notably too, despite claims that it will be operational by 2030, the Boom still doesn’t have an engine. Boom is now “assessing market requirements and design alternatives.”

Boom Chief Executive Blake Scholl says their demonstrator, the XB1, and its bigger sibling the commercial airliner, Overture, are leveraging technology from the days of the Concorde, rather than starting from scratch.

So the dream persists, despite the lessons of history.

The poster child for the failure of SSTs is the Aerion Corporation which tried to develop a10-passenger “boomless cruise” supersonic bizjet. After almost twenty years work, Aerion closed shop in 2021. By then it had designed a plane that it claimed would fly supersonically without a sonic boom. Aerion should have had everything going for it – a partnership with Boeing and purchase commitments totalling $11 billion from FlexJet and Netjets. It said it would launch its first commercial flights by 2026. Yet despite the huge backers – it still did not have enough money.

“Aerion had put together amazing talent,” says analyst Rollie Vincent, who consulted to Aerion. “The number of PhDs per square foot was off the chart. “But they weren’t building things, they were trying to refine design and purify aerodynamics. At some point, everybody, including investors, wants to see parts.”

Building real life parts early in the design process is the route Boom took. It spent $150 million, more than half of $270 million it raised, building the XB1 demonstrator dubbed “Baby Boom.” Though Baby Boom’s design may be far removed from the Overture jetliner sold to United and Japan Airlines, having something to fly assuaged investors scepticism.

The problem is that the realist bankers are not sure just how much business-class travellers are prepared to pay for a supersonic ride. Noting the quality of premium cabins today, with wifi connectivity, lie-flat seats and privacy pods, Richard Aboulafia wonders if cutting flight time in half is worth cramped seats.

The obvious answer to getting there quicker is not faster planes but reducing airport time. The current five-hour processing times in many Europe and US airports makes supersonic flight pointless.

Like Concorde, and more recently SpaceX, government support will needed. Subaru, Mitsubishi Heavy Industries and several other companies formed Japan Supersonic Research with a goal of having an SST passenger jet by 2030. They partnered with the Japan Aerospace Exploration Agency and have access to JAXA research going back to 1997.

“No single nation can develop supersonic transport on its own, since this requires an enormous amount of capital and the integration of many advanced technologies,” Dr Takashi Ishikawa, director of the space agency’s aviation program, wrote on the government website.

So it looks like it is back to the days of Concorde which required massive funding from both the British and French governments. The trouble is, I can’t imagine that any reasonable government has the appetite to fund another SST.

South Africa’s own CAD flight of fancy – the Pegasus VTOL bizjet.

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