The Perfect Airplane- page 3 | Flight Today | Air & Space Magazine
If engineers can corral liquid hydrogen, reshape pressure waves, and make fuel from algae, future airline passengers will travel around the world at hypersonic speeds in strange-looking aircraft. (Reaction Engines Ltd/Adrian Mann)

The Perfect Airplane

Fast, green, and quiet. Come on, brainiacs, you can do it.

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(Continued from page 2)

“Politicians have overdone these things,” says Joseph Schetz. “In the public mind, the sonic boom was going to mow down buildings and knock over cows, kill whales. It’s literally like slamming a door.”

Matters are even worse when it comes to the touchy matter of alternative fuels. Researchers have proposed all sorts of sources—soybeans, sunflower seeds, babassu nuts, coconuts, palm oil, and algae—for biofuels. Some of these wild potions have even been tested in flight, in genuine, honest-to-God airliners.

In December 2008, an Air New Zealand Boeing 747 departed Auckland carrying a blend of 50 percent Jet-A and 50 percent jatropha oil. (The jatropha plant’s seeds, when crushed, yield an oil usable as fuel.) Over two hours, one of the jet’s four engines ran on the blend and performed normally. A little over a week later, on January 7, 2009, a Continental Airlines Boeing 737 accomplished essentially the same feat over Houston, Texas. (Its particular blend was 50 percent Jet-A, 47.5 percent jatropha oil, and 2.5 percent algae.) Separately, Japan Airlines was planning to launch a Boeing 747 running on a biofuel component blended of one percent algae, 15 percent jatropha, and 84 percent camelina oil. (Camelina oil comes from an oilseed plant that also produces vegetable oil and animal feed.) Air France, to complete the picture, was contemplating the most radically chic and stylish fuel of all, made from little Roquefort cheese morsels rolled in crushed walnuts. (Not really.)

“The most attractive one, but at high cost, is algae,” says Schetz. “It grows very fast. It would be genuinely renewable. Plus, if you tailor your feedstock, you might end up with even more attractive fuel. You can’t tailor what’s in crude oil.”

The airliner of the future, then, is a combination of design studies that may or may not result in practical devices and vehicles, chancy schemes for reducing sonic booms, and alternative fuels that may be too expensive to produce on a mass scale. In light of which, one has to wonder if the prospect of propelling thousands of people daily across vast distances at tremendous speeds while bothering no one and leaving the environment no worse off is anything more than a dream. While such a goal doesn’t seem to violate any known law of nature, there are other laws that need to be considered: Murphy’s Law, Hofstadter’s Law (“It always takes longer than you expect, even if you take into account Hofstadter’s Law”), and the Almost-Law-of-Nature, which states that research-and-development costs are always far greater in the end than they were expected to be in the beginning. (The Concorde supersonic transport, for example, was six times more costly to develop than it was initially projected to be.)

Even so, hypersonics might be inching toward reality. David M. Van Wie of Johns Hopkins University’s Applied Physics Laboratory was an organizer of a 2008 international conference on hypersonic systems and technologies, from which emerged a distinct message. “The big takeaway we’re able to observe right now is that these hypersonic technologies are moving out of laboratories and into flight test demonstration,” says Van Wie. “Technologies that have been for years and years studied in wind tunnels, and by people doing analysis, are now being explored in flight experiments. Not at the level of airplanes yet, but in drones and rocket-propelled test vehicles.”

So when will we be flying the airliner of the future? The Europeans already have the answer: by the year 20XX.

Ed Regis is the author of seven science books, most recently What Is Life? Investigating the Nature of Life in the Age of Synthetic Biology (Oxford University Press, 2008).

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