Secrets: Good news of bin Laden's death may be followed by bad news of Pakistan giving China a peek at our downed helicopter. Will we be threatened by our own technology? They are something out of the latest Batman flick, the modified Black Hawk helicopters that were used in the raid on Osama bin Laden's Pakistani compound. With a curious hublike housing around the unusually configured rear-rotor, among other things, it was clearly designed to be as quiet and stealthy as possible. When one of the copters clipped a wall in bin Laden's compound, it had to be destroyed, leaving...