The Enola Gay exhibit finally opens today for public viewing at the National Air and Space Museum. It's mostly metal.

The focus is on hardware, not the nuances of history. It's about a big shiny plane and its determined crew. It's like a passage from a Tom Clancy novel, converted to three dimensions.

As for the destruction of Hiroshima: "I really decided to leave it more to the imagination," said Smithsonian Secretary I. Michael Heyman at a packed news conference yesterday morning attended by at least 26 TV camera crews and a U.S. Park Police SWAT team on the lookout for trouble.

Fifty years ago this summer, the B-29 named after the mother of its pilot dropped the atom bomb that instantly destroyed the Japanese city of Hiroshima and, with the atomic bombing of Nagasaki three days later, hastened the end of World War II. The Enola Gay's trip to the northwest corner of the Air and Space Museum has been far more tortuous than the flight it took the morning of Aug. 6, 1945.

For years the Smithsonian Institution had the plane, and was steadily restoring it to vintage condition. But the decision to display it as part of a lengthy contemplation of the birth of the Atomic Age, and on the anniversary of the end of the war, proved disastrous. A 500-page rough draft drew furious protest from veterans groups, who contended that it ignored Japanese wartime atrocities and unfairly questioned the decision to drop the bomb. The Smithsonian received more than 30,000 pieces of angry mail. The exhibit script was revised four more times. Meanwhile, the re-revisionism triggered a furor among Japanese who felt the exhibit should demonstrate the devastation of the bombing and the moral questions it raised; that is why Tuesday's media preview drew a heavy contingent of Japanese media. Finally, amid a debate over how many Americans might have died in an invasion of Japan, Heyman decided to scrap the show altogether and replace it with something far simpler.

"I don't believe that this is a glorification of nuclear weapons," said the bow-tied Heyman. "It says, This is the Enola Gay. It dropped the bomb that ended the war.' It doesn't take a position on the morality of it."

But there is no doubt that the more traditional veterans groups will be happy with the end result. Paul Tibbets, who piloted the Enola Gay, sent a letter of congratulations after touring the exhibit, saying he was "pleased and proud" of it. Peace activists, meanwhile, held a soggy press conference yesterday morning in a drizzling rain to denounce the museum's actions. There are also plans for an all-day protest today beginning at 10 a.m., when the museum opens.

"To display the Enola Gay without context, and without the considerable historical information and interpretation that is available, is to glorify and legitimate the use of nuclear weapons," said Jo Becker of the Fellowship of Reconciliation, speaking on behalf of a coalition of peace and religious groups.

The exhibit is short, Spartan and almost silent by the recent standards of the Smithsonian. It would be impossible to create a museum exhibit about the plane that dropped the first A-bomb without mentioning that it instantly killed more than 78,000 people -- some estimates go much higher -- but the museum has almost managed to pull it off.

The exhibition space, including interior walls and lighting, were already in place when the full exhibit was canceled. The museum scrambled to fill up the bare walls and empty rooms. Solution: Add more hardware.

So the first thing the visitor sees is an enormous piece of the Enola Gay's tail. Nearby are words and pictures about how the plane was restored after it sat for many years outdoors at Andrews Air Force Base.

On the other side of the room, up high, is an aileron, a wing flap. In the next room are two engines, and a video, again about the plane's restoration. Around the next corner are a propeller and propeller parts (spinner, motor, brake, hub, power gear assembly, cuff, blade), but by this time the visitor will be riveted on the gleaming B-29 itself, or at least the biggest chunk of it, 53 feet of the forward fuselage, a wingless tube.

Hanging beneath the plane is a green bomb casing like the one that held "Little Boy." A sign reassures visitors that the Enola Gay is not radioactive and poses no danger, and that the bomb casing does not contain an actual bomb.

The original exhibit would have explored the long-contentious question of whether the bomb was needed to end the war. The finished exhibit skips the issue completely. Heyman told reporters yesterday that exploring this question would require "voluminous texts and interactive debate which cannot adequately be done in the context of an exhibition which must, in the case of the Smithsonian, be finely balanced."

Instead, there is a two-paragraph statement on one wall summarizing a conventional view of why the atomic bombs were dropped on Hiroshima and Nagasaki. The bombs "destroyed much of the two cities and caused many tens of thousands of deaths," the wall sign says. "However, the use of the bombs led to the immediate surrender of Japan and made unnecessary the planned invasion of the Japanese home islands. Such an invasion, especially if undertaken for both main islands, would have led to very heavy casualties among American, Allied and Japanese armed forces, and Japanese civilians."

Beyond the fuselage, the visitor comes to a theater with a 16-minute video about the 509th Composite Group, led by Lt. Col. Tibbets. The video opens with battle scenes: fighter planes strafing ships, Marines raising the flag at Iwo Jima, bombs bursting. The crew members are shown in training in Utah. One says, "We just knew it was going to be a big explosion."

Over Hiroshima, the bombardier picked out a bridge as his target. The bomb fell true. The explosion rocked the Enola Gay from 10 miles away. The tail gunner looked back and saw the mushroom cloud and photographed it. "It also showed the turbulence engulfing the city and moving out into the foothills. And the only thing I could see of Hiroshima was one of the docks and the bay."

About 20 seconds of the video are devoted to the effects of the bomb: the scorched and flattened cityscape, some murky hospital shots, the back of what might be a corpse, a man with a blistered arm. The voice-over, from an Enola Gay crew member, states that the Japanese would not acknowledge what happened in Hiroshima and thus it was necessary to drop the second atomic bomb.

Heyman, who took over the reins of the Smithsonian in the middle of the controversy, said, "I thought very seriously about putting more pictures in this exhibition that would show the devastation." But he decided that any such pictures would have to be "counterbalanced" by images of heavy losses by American troops in the Pacific as they neared the invasion of Japan.

On the whole the exhibit is a departure from recent Smithsonian endeavors, which have been heavy on word panels, some of them featuring sentiments far more common among left-leaning university professors than among most tourists. People just wanting to look at impressive paintings were told that the West was won by Europeans through genocide of Native Americans. People who wanted to know about science in American life learned about racism and sexism in academia, and environmental damage from DDT. Conservative pundits and politicians have attacked the Smithsonian for using taxpayers' money to send visitors on a guilt trip.

Air and Space Museum Director Martin Harwit resigned earlier this year in the wake of the Enola Gay flap. Whether this attenuated, nuts-and-bolts exhibit is an aberration or the start of a new trend is yet to be seen.

Eventually the entire Enola Gay will be reassembled and moved to the new Air and Space Museum extension planned for Dulles International Airport, to be placed on permanent exhibition. The rest of the plane still needs work, including painstaking polishing. Anne McCombs, a restoration specialist who has spent years supervising the job, said yesterday that she hopes people like the new show even if it lacks historical context.

"To me the main thing is, it's the real thing," McCombs said. "It's not an illustration in a book. It's not film footage. It's the real airplane. This is the object that was used to change the history of the world." CAPTION: Japanese reporter Seitaro Murao files his story from in front of the Enola Gay at the National Air and Space Museum. The exhibit is big news in Japan, where some are angry because it no longer focuses on the devastation in Hiroshima and Nagasaki. CAPTION: Hiroshima survivor Kouichi Yasui addresses a protest against the exhibit outside the Air and Space Museum.