RAMON A. MAYOR Materials and Mechanics Engineering Pratt & Whitney WEST PALM BEACH, FLORIDA
I LOVED YOUR STORY ON THE FUTURE OF flight for the traveling public. There is also a very exciting project by the second largest commercial-aircraft manufacturer in the world, Airbus Industrie. The Airbus A3XX will be the world’s first twin-aisle, twin-deck aircraft, carrying between 550 and 650 passengers more than 7,600 nautical miles–that’s bigger and more luxurious than any plane flying today. Airlines are working with Airbus on the design of the A3XX, scheduled to enter service in 2004. Due to its unparalleled size, the A3XX will offer fascinating options to airlines, including a below-deck health club, a business center and even a piano bar. Just like Avis, at No. 2, Airbus, we try harder.
MARY ANNE GRECZYN Communications Manager Airbus Industrie North America, Inc. HERNDON, VIRGINIA
title: “Flights Of Fancy” ShowToc: true date: “2023-01-09” author: “Maria Walker”
There’s no way of knowing, but this much is certain: legions of engineers around the world have been attacking the myriad problems associated with supersonic travel ever since the Concordes first began rumbling down runways in the 1960s. They are at it still. Japan is testing models. Entrepreneurs are hatching business jets, France is contemplating its own supersonic program and researchers are dreaming up planes that fly as fast as rockets. Listening to them, it’s almost possible to believe that faster-than-sound travel might one day be the norm, rather than merely a specialty for the fashionable rich.
To be sure, supersonic transports, or SSTs, are terrifically difficult to pull off. Passengers will pay only a modest premium for the privilege of flying in them. Because SSTs trail shock waves, which account for the notorious sonic boom, they are restricted to a narrow market of overseas flights. And SSTs get no exemption from ever more stringent airport noise and environmental regulations.
Any new commercially viable SST would have to best the Concorde by a long shot. It would have to carry two or three times the Concorde’s 100-or-so passengers. It would have to cross the Pacific Ocean without refueling, which calls for an innovative new airframe that cuts supersonic drag to an absolute minimum. And those noise restrictions mean requiring it to take off and land using less thrust than the noisy Concorde. It’s enough to drive an aerodynamicist crazy. Engineers recite a litany of such conflicting requirements, which push development costs sky-high–to $30 billion by some estimates. That’s a lot of money to bet on a project that sits outside the mainstream. The leading edge of plane design is the superjumbo Airbus A3XX, built to ferry the most passengers at the least cost per head.
Yet the lure of supersonic travel remains strong. In March 2002, Japan’s National Aeronautics Laboratory plans to test a one-tenth-scale model of a supersonic transport, NEXST 1. It will ride piggyback on a rocket to an altitude of 17 kilometers, separate from the booster and glide earthward, testing how well its sleek shape reduces drag. In 2005, a NEXST 2 is slated to fly with its own engines. By 2015 Japan hopes to build an SST capable of carrying 250 passengers from Tokyo to Los Angeles in four hours.
Can Japan’s aerospace industry pull it off? NASA engineers think so. They were developing a plane the size and range of Japan’s but 25 percent faster–designed to fly at 2.5 times the speed of sound. Their design was twice as efficient as the Concorde at subsonic speeds. But tighter noise restrictions were announced at a critical juncture in the program, forcing NASA back to the drawing board and giving airplane makers cold feet.
William Gilbert, a technical manager on the NASA program, believes that the technology favors a slightly slower, but still supersonic, plane–such as Japan’s. “We wanted to do 12-hour flights in four hours,” he says. “But if you bring the speed down a bit, you still have a very fast plane, and you get a lot more leeway in the design.”
This lesson is not lost on Japan’s NAL. Its nine-year, 28 billion-yen program is testing whether a plane could be built to fly no faster than the Concorde–just better. “The Concorde is small and noisy and less than efficient,” says Dr. Kimio Sakata, head of NAL’s Advanced Technology Aircraft Project Center. “Our new aircraft must be commercially viable and environmentally friendly.”
Japan wants to share costs of a new SST with the United States and Europe. A French government task force is due to weigh in next week on a new SST program, but so far, despite last week’s crash, enthusiasm is high. “The idea is to have a much bigger plane than the Concorde so that it can actually make money,” says Serge Bonnet, an engineer at the newly formed European aerospace giant EADS. “It’s going to be a much more democratic plane.” Even so, any European SST initiative would compete with the $12 billion earmarked for the A3XX Airbus carriers.
Russia is also enthusiastic about SSTs. Russia, after all, developed the Tu-144 back in the 1960s, but scrapped the program after one of the planes crashed in Paris in 1973. Its research labs are teeming with expertise gleaned from work on military planes as well as collaborations with NASA and Boeing on the recently canceled U.S. supersonic effort. What the Russians lack, of course, is cash.
If Japan is successful in whipping up enthusiasm–and funds–for an SST consortium, it would put its aerospace industry at the cutting edge of aerodynamics, airframe construction using lightweight composites, jet engines and other technologies.
While national projects work to shape the future of big transport, entrepreneurs are trying to bring small planes through the sound barrier. Smaller planes leave behind quieter sonic booms, and with some fancy design work, it may be possible to reduce the boom to an unobtrusive “pop.” That might open up land routes forbidden to larger transports like the Concorde. Business travelers also have a tolerance for high prices.
Some engineers believe that a supersonic business jet could be built for a mere $1 billion. Richard Tracy, president of Reno Aeronautical Corp. in Nevada, is one of several who are trying. He’s got a design up his sleeve for an airplane wing over which air flows exceptionally smoothly at supersonic speeds and tolerably well at subsonic speeds, which means his plane might meet airport noise requirements and be able to fly over land. A demonstration flight is planned in two years. “We could build a working plane in five to seven years, provided we got the backing,” he says.
Tracy is the first to admit that those funds will be hard to find. But eventually, some engineers say, supersonic travel is bound to make more economic sense than subsonic travel. Here’s why: at supersonic speeds, air flowing over a wing gives rise to very little turbulence. So, in theory at least, supersonic travel is actually more efficient–given the right design–than subsonic travel. Oddly, this effect is more pronounced at extreme speeds. According to Preston Carter, an aerospace engineer at Lawrence Livermore Laboratory in California, an airplane traveling at Mach 8, or eight times the speed of sound, could conceivably fly four times farther on a tank of gas than a subsonic plane.
Intrigued by the possibilities, Carter a few years ago began noodling a design for just such a hypersonic plane. The result is HyperSoar–a combination rocket and advanced jet that would reach Mach 10. Of course, its sonic boom would make the Concorde’s sound like a champagne bubble in comparison; HyperSoar would have to take off from a remote location, such as a desert in Nevada. The plane would reach the outer atmosphere in minutes, skim along for an hour or so like a rock on a pond and make a white-knuckle descent to a destination half-way around the world. Carter, whose design relies on fancy jet engines NASA is developing for its HyperX plane, hopes to fly a prototype in five years.
But where’s the money to build these contraptions? Carter, for one, has no illusions about the market for supersonic people-movers. For the time being at least, he is pitching HyperSoar as a vehicle for delivering intercontinental mail very, very quickly. “It’s a proven market,” he says. Will people or packages ride the next big supersonic plane after the Concorde? For now each stands about the same chance.
