The Jet Engine: A Futuristic Technology Stuck in the Past

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“Falcon Heavy, in a Roar of Thunder, Carries SpaceX’s Ambition Into Orbit.” So reads a New York Times headline on the biggest spectacle of the week. Elon Musk’s latest rocket blasted into the atmosphere with David Bowie’s iconic “Space Oddity” playing on auto-repeat, listened to by no one. Crowds cheered as the rocket roared upon takeoff—carrying a Tesla Roadster as payload, no less—and roared again as the boosters delivered themselves safely back to Earth.

The sound of jet propulsion can be both mesmerizing and forgettable. On a recent trip to Washington, D.C., I became distinctly aware of a succession of rumbles in the sky early each morning: the steady sounds of the first banks of commercial airliners taking off from Reagan National Airport, across the Potomac. This is nothing out of the ordinary: just the groan of turbofans churning the outside air into propellant thrust so an airliner can ascend after takeoff.

It might seem silly to even remark on it. This happens to me more often than I’d like to admit: I’ll hear a jet rumbling above, and gaze up and say, “Wow!”—and whoever I’m with stares at me like I’m some sort of Neanderthal. But this dull roar denotes a truly astonishing feat happening each and every day, on regular and tight schedules. These are the workhorses of the sky, transporting people and cargo around the planet for labor and leisure, the grinds of work and duty commingling with the fantasies of vacation and pleasure. Turbofans propel both bodies and boxes around the globe.

Yet here’s what’s weird: The same technologies that quite literally thrust people and things into space and the future are also the very things that might be holding humans back from truly radical, forward-looking innovations.

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Lately there has been some buzz about new developments in electric turbofan engines. An advancement would result in a quieter, more fuel-efficient mode of jet propulsion—and thereby a cheaper and less polluting form of air travel. Promotional spots for the products often show energy diagrams with bold green arrows and lines, or sleek aircraft soaring above verdant, rolling landscapes. Rolls-Royce, for instance, is collaborating with Siemens and Airbus to develop a hybrid aircraft on which one of the four gas-turbine engines—a turbofan painted green—will be powered solely by electric energy. The plane will have three normal gas turbofans as backup as the companies test the green engine for stress, safety, and reliability. The goal is to fly this test plane by 2020, suggesting that the technology could conceivably be put into use within the next couple decades.

The aircraft model for this particular test plane is a British Aerospace 146, or BAe-146. It’s a smallish, short- to mid-range aircraft with 70 to 112 seats, most commonly used for regional routes. It’s a distinctive plane, resembling a miniature cargo jet with a high-wing cantilever design and four comparatively small engines. This is a rather old plane, first flown in 1981 and no longer in commercial service in the United States. Only 144 of the 387 aircraft built are still in operation around the world. In other words, the green-engine testing is not being conducted on a wide-body, mainline carrier—the type of aircraft where the real money is for airlines as well as aircraft and turbofan manufacturers. Instead, an obsolescing aircraft is being used to test out new propulsion technology. It’s an investment in green energy, then, but perhaps more symbolic than realistic in terms of widespread, cost-effective use.

Of course, larger-scale equipment is also undergoing renewal and innovation. Rolls-Royce is developing a new Power Gearbox that will result in 25 percent greater fuel efficiency in their large turbofans by 2025, relative to the 20-year-old Trent 700 model.

Regarding their newer Trent 7000 turbofans, designed for the wide-body Airbus A330neo (250 to 440 passengers), Rolls-Royce confidently claims that these engines are “future-proofed on noise and emissions, with plenty of margin against both current and future environmental targets/legislation.” Rolls-Royce confirmed that this turbofan has been designed to meet guidance for projected regulations of emissions and noise, which have not yet increased in stringency. This both assumes a worsening state of affairs (more air-traffic congestion, greater ecological urgency, etc.) and assures buyers that these things have already been planned for and built into the engine. It amounts to copping to the tragedy of what’s coming, and then congratulating oneself for being so ready for it. It is a curious way to think about the future, if you pause to contemplate it.

And certainly, even as turbofan and aircraft manufacturers alike make appeals to cleaner technology, their goal is not to reduce human air travel. Regarding its A330 model, Airbus charts 1,694 orders for these planes, of which only 1,373 are fulfilled. The implicit message: Demand has not been met, which means building more planes, and faster. And this is presented as an ongoing condition. An airline manufacturer would never aim to satisfy the needs of all airlines once and for all, but rather to keep producing new jets ad infinitum. So even if the planes to come are powered by relatively cleaner Trent 7000 turbofans, the assumption—the goal—is to put ever more A330s in the sky. That somewhat complicates the straightforward aim of hitting “environmental targets,” as Rolls-Royce puts it. Individually, sure—but collectively, if more planes are in the sky?

Aviation futurists might argue that as old planes are retired, the newer, more efficient aircraft will simply replace these, and that consolidation will reduce overall flights and eliminate unnecessary routes. Yet it is clear that Airbus and Boeing are hardly going to turn away new business, or slow down production. Consider how Airbus boldly claims that their A320 family is the “world’s best-selling aircraft of all time”; and then look at how Boeing shows off their cornucopia of customers for their comparable next-generation 737. This is obviously a race for growth, not just efficiency.

Turbofan engines offer an audible reminder of the paradox of progress. As much as people may want to experience new things, they have to use old tools and means to do so. Sometimes those tools and means can function as blinders. People are tied to existing patterns, infrastructure, and systems even as they might want or need to do something different and truly innovative.

Leaving Washington a few days later, I was struck by the beauty of Eero Saarinen’s Dulles International Airport at dawn. The way it sweeps up from the ground, how it architecturally announces the grand project of flight. It feels like a paean to the jet age, a living monument of sorts.

As I plodded through the security-checkpoint slog to my gate, however, it occurred to me how stuck travelers are in this bizarre moment of the past, this mid-20th-century endeavor that is jet travel. Innovations in turbofan-engine design and technology may be well-intentioned and forward-thinking, at least in some sense. And the actual work that turbofans do day in and day out, hour after hour of nonstop chugging across the sky—it’s nothing less than incredible, from a technical standpoint. But, at the same time, the din of flight really can’t help but remind people of something that had its heyday several decades ago.

The bitter truth is that human air travel probably won’t get much better in the years to come. It might have reached certain limits in terms of speed, economy, and comfort. There are any number of signs that this is the case: climate change, limited resources, land-use constraints, wealth inequality, and so on. Recently, news broke about problems in the Rolls-Royce Trent 1000 engines that power the Boeing 787, which was first introduced in 2011: The turbine blades on two separate aircraft broke down during flight, resulting in severe vibrations and causing the aircraft to abort their journeys. Concerning these recent incidents, Warren East, the chief executive at Rolls-Royce, admitted an obvious but uncomfortable truth about turbofan parts: “They wear out.”

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For all of Elon Musk’s bluster, and even granting the incredible engineering brilliance behind SpaceX’s accomplishments, an odd detail slipped into one of Musk’s presentations on “making life multiplanetary”: The pressurized area of the payload section of his planned Mars spaceship is described as being “greater than the cabin of an Airbus A380.” The fact is meant to be impressive, but it doesn’t quite square with the expected duration of the trip to Mars. Three to six months traveling in a super jumbo jet? No thanks. Sixteen hours in an A380 can already drive one to the point of insanity, no matter how luxurious the accommodations. In a similar rhetorical move, the mass of this week’s star rocket, the Falcon Heavy, was explained by comparison to a 737—one of the most recognizable Boeing commercial airliners in service today. To envision a reusable space rocket as little more than a vertically aligned Southwest plane brings the stars down to earth indeed. The ambitions and technological marvels of Musk’s rockets are weighed down by the 20th-century baggage of commercial flight.

For now, the goal of human air travel seems to be to keep it going at any cost—as if humanity is still headed somewhere else, somewhere new. Rolls-Royce plans to “power the aircraft of the future,” as a company statement boldly puts it. And SpaceX is certainly working hard to produce another aspect of this future. But is the future in play here truly something revolutionary?

Whether encapsulated in the dreams of a billionaire technologist or nestled in the gear teeth of a next-generation turbofan, the roar of the future gets awkwardly dampened. It sounds a lot like the present, or maybe even more like the past. Understood this way, it makes perverse sense why Musk sent a car into outer space, going nowhere, as if to consecrate once and for all the 20th century as a final frontier.



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