An Idaho man says he piloted his homemade flying wing aircraft into Hill Air Force Base in 1987 in what apparently was an unofficial test of any radar-eluding qualities possessed by the plane - similar in appearance to the new B-2 Stealth bomber.

Gilbert E. Davis of Boise says the shape and construction of his aircraft, if not its 35-foot wingspan, is similar to the B-2 unveiled Tuesday by Northrop Corp. in California.Each essentially is two swept wings with a bulge in the middle for a cockpit. Both use composite structural materials where most airplanes are made of metals, although the multimillion-dollar bomber's synthetics certainly are more exotic than Davis' plastic foam and fiberglass.

To a lesser extent, Davis' airplane resembles a picture of the F-117A Stealth fighter the Air Force has flown secretly at night in Nevada since 1983 but announced just two weeks ago.

Stealth technology is supposed to help aircraft avoid detection by radar, allowing them to slip through enemy defenses. Just how the jet Stealth bomber and fighter are built to achieve this remains a secret of the Pentagon.

But Davis said space-age composite materials like carbon fiber reflect less radar than metal, and a flying wing's slim, smooth profile further reduces bouncing signals.

"The flying wing is hard to detect on radar," he said in a telephone interview.

Stealth is not what Davis had in mind when he designed and built his recreational machine as a prototype for a larger version he plans to sell in kit form. However, that apparently is what was tested at Hill a year after the plane was first propelled into flight by a snowmobile engine in 1986.

Hill spokesman Len Barry did not know the exact reason for the June 1987 test, but said, "Apparently, it did occur."

Davis had been invited to speak about his flying wing at the annual convention of the Utah Pilots Association, which had a dinner in the base officers club on June 5, 1987. He said then-Maj. Gen. Robert P. McCoy, since promoted to the Air Force Logistics Command in Ohio, had let it be known he would be in the control tower at 8 a.m. that day.

Davis said the word came down that the base commander wanted him to fly the radar approach.

Although they were not told why, both Davis and his brother, Ross Davis of Murray, feel the only sensible reason was to see how the flying wing would appear on radar.

The brothers approached from the north. Ross Davis, a former Army helicopter pilot, flew a metal, conventionally designed propeller airplane with a radio transponder emitting signals to help show its position.

"They did see me," Ross Davis said.

About 50 feet off his right wing, Gilbert Davis knifed through the air in his thin, fiberglass-skinned machine, which lacked a transponder.

Mission accomplished, the brothers flew by the tower and returned to Ogden Municipal Airport.

That night at the dinner, Gilbert Davis said, he asked McCoy about the results of the test. He said the general was like a seasoned poker player.

"You don't know what he's got in his hand," he said. "I couldn't find out what they saw or didn't see."