Behind the supersonic rise and fall of the Concorde, 15 years after its final flight

https://www.popsci.com/concorde-anniversary-future-of-supersonic-flight?dom=rss-default&src=syn


Here’s how the typical storyline of technology goes: something new is invented, then it becomes old, and then we replace it with a more advanced version. But in rare instances tech is so advanced that we’re not actually prepared to replace it by the time it ages out of fashion. Case in point: the Concorde. It was a plane ahead of its time—quite literally, as a flight from Paris or London to New York was so fast it’d actually land more than two hours before it took off: something that’s only possible today if you cross the International Date Line. The supersonic jet was supposed to usher in a new age of transportation, but just 27 years after its inaugural commercial flight the futuristic aircraft retired with no successor—15 years ago today, in fact—and supersonic passenger travel ceased to exist.

The reasons were manifold, but typically distilled into two major problems: the Concorde was not economical, and the sonic boom it produced was such a nuisance to people on the ground that it could only fly over water. The first and last generation of Concorde reached old age before anyone had managed to solve those problems, so nobody unveiled a shiny new model to replace it. But there’s hope on the horizon. In 2016, NASA announced a new program to develop a quieter supersonic aircraft and awarded a contract to Lockheed Martin, meaning that the general public may soon soar faster than the speed of sound once more.

A Supersonic Rise And Fall

After the Wright Brothers made the first flight in Kitty Hawk, North Carolina, on December 17, 1903, aviation developed at an incredible pace. Within two decades WWI was taking warfare to the skies and commercial airlines were ferrying customers around the world. On October 14th, 1947, aviation took another big leap forward; test pilot Chuck Yeager became the first human to break the sound barrier, achieving Mach 1 in the Bell X-1 rocket-powered aircraft, a collaborative project between the U.S. Air Force and National Advisory Committee for Aeronautics (NACA), the precursor to NASA. But the X-1 itself was designed primarily for research, not commercial passengers. Soon supersonic military jets were on the rise, but like the X-1, they were sprinters: they could only fly at Mach 1 for a few seconds, perhaps a few minutes at most, before they ran out of fuel. While this worked for small aircraft performing sharp maneuvers, large commercial airliners—which often travel in straight lines or gentle curves—would need to cruise at supersonic speed for a much longer period of time.

The progression did, however, inspire the commercial aviation industry to look into the creation of supersonic transports (SSTs), or civilian supersonic aircraft. While the X-1 proved we had the right tools to fly at supersonic speeds, a few major details needed ironing out, like the capability to cruise above Mach 1 for the duration of a relatively long flight, as well as the economic viability of such a project. Multiple countries, including the U.S., started research in the 1950s, but a slew of difficulties facing SSTs during development meant that just three nations would go on to build and fly such crafts: the United Kingdom, France, and the Soviet Union.

“The only European countries that had the interest, the technology, and the financing to design and build an SST were France and Great Britain,” says John Little, assistant curator at the Museum of Flight in Seattle. “They each wanted to develop an SST, but neither country could afford to do so on its own. So, somewhat reluctantly, France and Great Britain agreed to become partners and to develop an SST jointly.”

The U.S.S.R., on the other hand, was able to develop its Tupolev Tu-144 independently, though the airliner only made 55 passenger flights before the program was canceled due to high failure rate. (There was, for instance, a high-profile crash at the 1973 Paris Air Show.) The Concorde was by far the superior aircraft, making daily flights for nearly three decades.

Flying (And Spending) High

In order to make SST possible, Concorde engineers from the U.K.’s British Aircraft Corporation, France’s Aérospatiale, and the other companies contracted to work on portions of the aircraft (like Rolls-Royce, which designed the engines) had to develop new technologies or refine old ones, from the fly-by-wire controls in the cockpit (electronic interfaces versus analog ones) to heat-resistant tires to the elegant delta wing. “In my opinion, Concorde’s most innovative technology was the ability to cruise at Mach 2, or twice the speed of sound,” says Little. “After a few minutes of supersonic flight, most military airplanes would run low on fuel. By contrast, Concorde could cruise at twice the speed of sound for over three hours.”

Airlines rushed to place Concorde orders years before the plane was even built—more than 70 aircraft were ordered by 16 companies. But as the Concorde’s development progressed, so did the project’s cost. “Cost overruns were tremendous, going from £70 million to £1.3 billion,” says Aero Consulting Experts CEO Ross “Rusty” Aimer, a former pilot (that’s about $91 million to $1.7 billion in 2018 USD). Then the Concorde ran into other unexpected problems—although its faster trips meant it used less fuel on a journey than standard aircraft, environmentalists protested the high rate of fuel consumption (approximately 6,700 gallons per hour, compared to the Boeing 747’s 3,600 gallons per hour), as well as the potential damage the Concorde’s pollutants might do to the ozone layer at its high cruising altitude of 60,000 feet. And what might have been the biggest blow to the airliner was the banning of flights over land by air transportation regulators due to the sonic boom, which followed the aircraft in a 16-mile-wide trail. Thus the Concorde was limited to routes over water, and given its flying range of approximately 4,500 miles, it could barely cross the Atlantic, much less the Pacific. “The original orders from airlines around the world started to drop like a bad run on banks,” Aimer notes. “British Airways and Air France were the only airlines forced to order a small number due to political pressure and national pride.”

Ultimately, only 20 Concordes were ever built, including six prototypes: just 14, seven each for British Airways and Air France, ever entered commercial service. Despite being plagued with problems over the course of its development, the aircraft was highly regarded as one of most beautiful in the world—as well as one of the safest—and its exclusivity due to limited seats and sky-high ticket prices (in today’s dollars, a round-trip flight on the Concorde could cost upwards of $20,000, compared to the $6,000 to $10,000 you’d spend flying first-class on a subsonic Air France jet in 2018) created great demand. A massive fan base of aviation enthusiasts and high-profile passengers like celebrities and politicians grew quickly, and ticket sales soared.

Flying aboard a Concorde was a luxurious experience, akin to flying first class on one of today’s airliners. The notoriously cramped and noisy cabins never stopped guests from enjoying their journey: they sipped Champagne from glass flutes, dined on three-course meals served by hand rather than trolley, and indulged in after-dinner drinks. “We were trained to be efficient and elegant,” says Air France head purser Alain Verschuere, who served as a flight attendant aboard Concorde from 1999 till its retirement in 2003. “Air France was famous for this kind of class. The service was very nice, as were our uniforms and the decor aboard. We were very proud to fly on this aircraft. Even nowadays, 15 years later, passengers on my flights always say to me, ‘You were so lucky to fly on the Concorde!’”

But all good things must come to an end. Between the Concorde’s first passenger flight in 1976 and its last flight in 2003, the airliner was dealt some difficult hands—this aside from its economical and auditory woes during its development phase.

In With A Boom, Out With A Whimper

“When Concorde was conceived in late 1950s and designed in the mid-1960s, oil was cheap, jet fuel cost just pennies per gallon, and nobody foresaw that price increasing. Then came the Oil Crisis of 1973-1974, which caused the price of oil, and everything that was derived from it, including jet fuel, to soar,” says Little. “An increase of even a penny per gallon could mean the difference between operating a flight at a profit or a loss, and no airliner was more-susceptible to fluctuations jet fuel pricing than Concorde, which burned about 2,000 pounds of fuel per passenger while flying across the Atlantic Ocean.”

“Even worse, as global business travel shifted toward Asia, Concorde became less competitive. Because it could not fly supersonically over land, it could not fly to Asia eastward from Paris or London, nor could it fly westward, as it did not have the range to cross the Pacific Ocean,” Little adds. “Thus, ironically, in the long-haul market, where supersonic flight makes the most sense economically, Concorde was a non-starter.”

Market issues aside, there was also the main problem that burdens any aircraft—time. The fleet aged, and maintenance was extremely costly. By the end of the 1990s, given fuel and maintenance costs, as well as limitations to the route, the aircraft’s fate was effectively sealed. Then there was the final blow: On July 25, 2000, Air France Flight 4590, a Concorde bound for New York from Paris crashed just minutes after takeoff, killing everyone on board and several people on the ground. “Just one year later, the fleet was authorized to fly again, since we developed new technology that resolved the weaknesses that contributed to the crash,” says Jacques Rocca, Director of the Heritage Department at Airbus, which maintains most of the assets of the now defunct Aérospatiale. “But because of the 9/11 terrorist attacks, which happened during that year, less people were requesting to fly Concorde when it returned to service.”

The Concorde’s return was brief—the plane phased out of service in 2003, with the final flight taking place on October 24, ending the limited run of one of the most legendary aircraft in aviation history. “Essentially, the Concorde was more about technological prowess than economical reality,” says Aimer.

A Second Wind

There was no SST to replace the aged Concorde, so airline passengers have been cruising at subsonic speeds ever since. But 15 years later the world is more connected than ever, and there’s incredible demand for faster aircraft. “As Asia becomes increasingly central to the world’s economy, business travelers need a way to get to Asia quickly from Europe and the Americas,” says Little. “The first aircraft-maker that develops a hypersonic airliner [one that travels at Mach 5 or higher] that can fly between New York and Beijing in, say, three hours, will sell a lot of airplanes.”

Today, a number of companies are researching ways to resolve the Concorde’s shortcomings for both commercial airliners and business jets. “From an engineering standpoint, the big challenges will be to reduce the fuel burn, reduce the emissions, and reduce or eliminate the sonic boom—all will be extremely expensive to solve,” says Little. “For reducing fuel burn and emissions, the best option is to develop engines that do not require the burning of petroleum-based fuel. That option, however, will be risky for any manufacturer to undertake, and there is no guarantee of success.”

NASA is currently working with Lockheed Martin on an experimental aircraft, the X-59 QueSST, that will reduce the supersonic boom to a quiet thump. “It’s not about the specific material used, the level of attention to screws, bolts or seams. The most important aspect of the design is its shape—the outer mold line and what’s touching the air,” explains Erica Tierney, Program Communications and Media Relations at Lockheed Martin Skunk Works. “The X-59’s long pointed noise, the sharply swept wings, and shape of the canards ensure the individual pressure waves, produced at speeds faster than Mach 1, never converge to cause a traditional sonic boom.”

The plane is currently under development with a delivery date in 2021. Once Lockheed Martin hands the completed aircraft over to NASA, the agency will fly the X-59 over U.S. cities to study the effect of the sonic thump on the general population.

“NASA will recruit members of the community to participate in surveys each day during flight testing to understand how they respond to the sounds of quiet supersonic overflight,” says Peter Coen, Commercial Supersonic Technology project manager at NASA. “The data from flight tests will be given to U.S. and international regulators for their use in considering new rules that would allow commercial supersonic flight over land.”

Should the Federal Aviation Administration lift the ban on supersonic travel over U.S. land for quieter SSTs, aircraft manufacturers could use similar tech to develop new supersonic planes.

“The X-59 will be a breakthrough for the aircraft and transportation industries,” says Tierney. “It will make possible an entirely new global aerospace market, enabling passengers around the world to travel anywhere in half the time it takes today.”

But will the return of SSTs be in the broader commercial space for all types of passengers? Perhaps not—experts suggest supersonic travel might go in the direction of private planes, also known as business jets. “The business jet market is rapidly spinning up,” says Dr. James Ladesic, Professor of Aerospace Engineering and Associate Dean, Industry Relations and Outreach, College of Engineering at Embry-Riddle University. “SSTs are seen as having a niche that can work here, since business jets are generally smaller in passenger count and of significant price value in the market.”

Samme Chittum, author of Last Days of the Concorde: The Crash of Flight 4590 and the End of Supersonic Passenger Travel, agrees that the future is in business jets. “All current aerodynamic research indicates that the airframe of any quieter ‘boomless’ aircraft must have a small length-to-width ratio, much like an arrow—no wide-bodies need apply,” she says. “This narrow configuration is not amenable to carrying a lot of passengers to reduce passenger mile per gallon of fuel costs. If commercial supersonic aircraft do arrive, they will most likely be as small business planes for the super wealthy, not as bus transportation for the rest of us.”

NASA, however, hopes for a different outcome. “Our vision for the future supersonic flight is one in which the speed of travel benefits of aircraft like the Concorde are available broadly to the public,” says Coen. Should the X-59 be successful in its mission to reduce the sonic boom, we might all be flying faster than the speed of sound in no time.

via Popular Science – New Technology, Science News, The Future Now https://ift.tt/2k2uJQn

October 24, 2018 at 01:53PM

About peterjang73

A nerdy father of two, a husband of a beautiful and understanding wife, an engineer who loves anime and tinkering with PCs and games, but most of all, loves God.
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