Double the size of an Airbus A380? No problem, aerodynamicists say.
- By Michael Milstein
- Air & Space magazine, July 2006
(Page 3 of 5)
“If you’re going to do a big plane, why don’t you do something grand?” McMasters says. “The airlines like big planes because they move lots of people. Why not build something people will like too?”
McMasters’ seagoing Super Clipper is a fanciful extrapolation from his study of large aircraft configurations. He has also studied the prospect of a giant flying wing, a design that NASA has continued to study. At this point, Boeing’s interest is purely in military applications, and the company will fly a scale model of the Blended Wing Body aircraft at NASA’s Dryden Flight Research Center in California this fall. If a full-scale commercial version were to be developed, it would face the same problem the A-380 faces: airports.
London’s Heathrow is the third busiest in the world (after Atlanta and Chicago) and, as the airport handling more international travelers than any other, probably the most cramped for space. When Airbus designers approached airports around the world starting in 1996, Heathrow was enthusiastic because the A380’s capacity could squeeze more people into each of its coveted landing slots. The airport now expects 65 superjumbo flights a day by 2015.
But big airplanes create big demands on the ground: Heathrow is spending about $800 million to rebuild itself, widening runways, adding taxiways, lengthening baggage conveyors, and renovating a terminal to create four superjumbo-size gates almost as wide as Big Ben is tall. The airport is also building a new terminal, to be completed by 2011, that will include 14 gates that can accommodate the A380; two of the 14 opened this year.
In Singapore, where Singapore Airlines has ordered 10 A380s, with options for 15 more, costing a total of $8.6 billion, and where the first commercial A380 flight will likely take off early next year, Changi Airport is expanding 19 gates with extra seating, restrooms, and three jetways to handle A380s. Crews at Changi, which promises to be a hub for the megaliners on crowded Asian routes, have widened runways, expanded runway-taxiway intersections, and added shields to block the intense blast from the A380’s engines.
Airbus designed the A380 so airports wouldn’t have to strengthen existing runways. Though it weighs far more than a 747, its tires put no more pressure on runways because its weight is spread out over more wheels: 22. The immense weight of the new airliners does require some airports to reinforce bridges they will use. Its span and engine placement require them to widen runways from 150 feet, the standard for a 747, to 200 feet. Some airports, such San Francisco International, will work around that requirement by closing adjoining taxiways when an A380 arrives.
Airbus has strained to coax every bit of per-passenger performance possible from its superjumbo, and that’s the reason the airplane has two decks. Airplanes that pack people onto two levels—like the A380—or even three levels—like Kroo’s superduperjumbo—make more efficient use of their space. Kroo figured that by stacking 1,500 passengers in an airliner’s triple-deck fuselage, for example, he would reduce the ratio of nonlifting fuselage area to lifting wing area, which would reduce the power needed to carry each person. (Pity the poor pilot who’d have to stand there and say goodbye as all those people file off.)
But the payoff multiplies not only because per-person thrust is optimized but because the basic costs of flying any airliner—the salary of our friendly pilot, for instance—are spread across the ticket price of more passengers, so the cost of moving each person is smaller.