On a Cushion of Air

Graceful as they are in the air, today's jetliners have become increasingly awkward on the ground. Taxiing under their own power, they use inordinate amounts of fuel; maneuvering them in maintenance areas and hangars is tough and timeconsuming. And such troubles will only grow worse with the introduction of the 490-passenger Boeing 747 and the supersonic transport. One way to solve the problem, say engineers of Seattle's Aero-Go Inc., is to keep the planes aloft even when they are on the ground. They have done just that by developing a device that can literally float giant jetliners over concrete aprons, taxiways and hangar floors on a cushion of air.

Hole in the Doughnut. Aero-Go's gadget goes to work after ground crews have rolled a plane's wheels onto small, dolly-like platforms. Underneath each platform are air bearings--flat disks made of plastic-fabric materials. When air is pumped into the disks, they assume a doughnut shape, raising the platform and its heavy load from 1 to 3 in. As the bearings become inflated, air escaping through perforations in the doughnut seeps underneath it. That thin film of escaping air suspends platform and plane above the concrete surface.

Floating on air and practically freed from friction, a 160-ton Boeing 747 can be pulled effortlessly around airports; it can even be shoved sideways in a cramped hangar by a small tractor. The awkward task of calibrating a plane's compass* will also be eased by the new device. The big planes will be floated onto a 46-ft. diameter turntable that will be suspended 3 in. above the ground on air bearings. A tractor will then turn the plane to any angle on the freely rotating turntable, eliminating considerable maneuvering and excessive wear on the tires.

In the Kitchen. Aero-Go is also building bearings for other uses. It has put them on experimental models of small, airborne cars propelled by large fans and designed to move people as easily as planes. The Navy plans to use the bearings for hauling giant ship propellers and shafts around the Pearl Harbor shipyard. NBC has bought air bearings to shift heavy bleachers around TV studios, and several manufacturers are already using them to move heavy equipment and products across factory floors. Air bearings placed under a one-ton machine, for example, enable a workman to move it across a smooth surface with a push of less than 15 Ibs. Another manufacturer, Airfloat Corp. of Decatur, Ill., has designed air bearings for an eleven-ton concrete radiation shielding door at the Los Alamos Scientific Laboratory, and for easily maneuverable dental chairs.

Air bearings can be connected to any convenient source of compressed air and usually require little pressure. Aero-Go has even developed a fourelement air bearing device that will enable a housewife to shove a 600-lb. refrigerator around the kitchen floor. Its power source: the exhaust air flow of an ordinary vacuum cleaner.

*Because an aircraft's metallic structures and its electronic instruments can cause its magnetic compass to give incorrect readings, the compass must be adjusted after installation, as the plane is pivoted through a full circle on the ground.

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