Air Force Takes the Wraps Off Supersecret Spy Plane--10 Years Later

WASHINGTON —  The Air Force has unveiled a unique “stealth” airplane built more than a decade ago in California in the strictest of secrecy. Parts of its pioneering radar-evading design live on in today’s B-2 stealth bomber.

Meant to be a surveillance plane that could fly close to a battle front with minimal risk of being detected by radar, the plane was test flown 135 times from 1982-85 but then scrapped. It has been in secret storage ever since.

The Air Force had never acknowledged the existence of the project, which was code-named Tacit Blue. The plane never flew real surveillance missions.

In declassifying the project, the Air Force provided color photographs and a videotape of the plane in flight. The only one of its kind ever built, the Tacit Blue aircraft will go on public display May 22 at Wright-Patterson Air Force Base, Ohio.

Shaped like no other known military aircraft, Tacit Blue resembles an upside-down bathtub with stubby wings. At 55 feet in length, it is a little shorter than the Air Force’s main fighter, the F-15; its wingspan of 48 feet is only a little wider than the F-15’s. It was not meant to carry weapons.

The plane was built between 1978 and 1982 by Northrop Corp., at its Hawthorne, Calif., plant for $136 million, Lt. Gen. George Muellner told a Pentagon news conference last week. Testing the plane cost $29 million more, he said.

“It has been a pretty well-kept secret,” Muellner said.

Aircraft enthusiasts have speculated for years about the existence of a supersecret spy plane some dubbed “Aurora,” but that plane--which U.S. officials deny ever existed--was supposed to be supersonic. Tacit Blue was subsonic.

John Pike, an aviation specialist at the Federation of American Scientists, said none of the private groups that hunt for clues to secret military programs had ever spotted Tacit Blue or speculated on its existence. Pike said the full story of Tacit Blue and other secret aircraft is yet to be told.

“I would be surprised if there weren’t several more” like this yet to be declassified, Pike said.

Unlike other planes, the intake for Tacit Blue’s two turbofan engines is on top of the fuselage. The vertical stabilizers on the rear of the plane form a “V.” The plane’s underside appears to form an unbroken flat surface from front to rear.

Two aspects of Tacit Blue’s innovative radar-evading characteristics were adapted for use on the B-2 bomber, Air Force officials said. One is the combination of curved and linear surfaces; the other is the special composite materials used on the surfaces to absorb signals from radars trying to track it.

Muellner said the project was canceled in 1985 when the Air Force decided it made more sense to build what is now the Joint-Stars ground surveillance plane.

Joint-Stars, which uses a modified Boeing 707 air frame, does not have radar-evading capability but carries a bigger radar than Tacit Blue could. The bigger radar enables Joint Stars to provide wide ground coverage while staying out of range of hostile air defenses by flying farther from the battle front.

Joint Stars planes were flown in the 1991 Persian Gulf War and in the current NATO-led peace mission in Bosnia, although the plane technically is still in the test and evaluation phase. It is scheduled to be officially operational in 1997.

Muellner said the Tacit Blue plane was flown by only five pilots. They operated it from several different locations, but he would not say where. There were 135 flights totaling 250 hours between Feb. 5, 1982, and Feb. 14, 1985, he said. All were in daylight.

Even though the plane stopped flying more than 11 years ago, the Air Force kept it secret because some of its unique stealth technologies were adapted for both the B-2 bomber and a once-classified Air Force strategic missile. After the first B-2 entered the fleet in 1993 and the missile program was canceled in 1994, Tacit Blue no longer needed to remain secret, Muellner said.