Around the world on a tank of gas.

Around the world on a tank of gas

Early on the morning of Dec. 14, aspindly, ungainly, plastic-and-paper aircraft, dragging its fuel-laden wings, took off from EDwards Air Force Base, Calif. Nine days later, the airplane, Voyager, landed on the same field after completing the first nonstop flight around the world without refueling.

"It was a good, solid engineeringfeat," says Joseph W. Stickle, chief of the low-speed aeronautics division at NASA's Langley Research Center in Hampton, Va. Although the flight represents no single, major technological breakthrough, he says, it's the culmination of recent advances in composite materials, in airfoil design and in weather observation and navigation.

The experimental plane's designersput together several state-of-the-art technologies to create a unique, feather-weight aircraft specifically designed to accomplish its one mission. The plane's self-supporting skin consists of a honeycombed paper core sandwiched between layers of carbon-fiber tape impregnated with an epoxy resin. Firewalls of special lightweight ceramics able to withstand temperatures greater than 2,000 [deg.]F separate the aircraft's two engines from the fuel tanks. The only metal components are the two engines and a few nuts and bolts. Although its 111-foot wingspan is longer than that of a Boeing 727, the empty, nofrills aircraft weighs only 1,858 pounds.

Its smooth skin and novel airfoilshape also help reduce drag. The absence of joints and protruding rivets typically found in wings fabricated from metal allows air to flow smoothly in even layers over the two wings. This couldn't have been done without the use of composite materials, says Stickle. However, this flight was too short to address concerns about the long-term durability of composite materials -- their resistance to fatigue, ultraviolet light and lightning.

When Voyager took off, it carriedabout 1,200 gallons of fuel. After its nineday westward circuit covering more than 25,000 miles, fewer than 10 gallons of usable fuel were left. At an average speed close to 115 miles per hour (including tail winds), the aircraft's miles-per-gallon performance rated higher than that of many automobiles.

Satellite-based weather observationsand navigational aids enabled the pilots to avoid thunderstorms and dodge tropical typhoons in a flight that occurred mainly over water. Five or 10 years ago, when such aids were unavailable, the flight would have been much more hazardous, says Stickle.

In terms of human endurance, theVoyager flight was probably more demanding than any previous airplane flight. The pilots, Dick Rutan and Jeana Yeager (no relation to test pilot Chuck Yeager), had to cope with being cooped up in a cabin that's barely the size of a phone booth. Turbulence repeatedly knocked the pilots around. In Rutan's words, the aircraft was a "beast" to fly, often rolling, heaving and lurching through the air. The flapping of its wings, which could flex as much as 30 feet, didn't help. Because there was no soundproofing, Rutan and Yeager also had to put up with a constant, deafening roar from the plane's engines.

As he approached Edwards Air ForceBase at the end of the flight, Rutan radioed, "I must admit there [were] times during the flight when I didn't think it was possible."