Images of what appears to be the tail-rotor of one the helicopters used in Sunday's raid on Osama bin Laden's compound at Abbottabad, Pakistan, are hitting the internet, and may be a glimpse at something special. The parts don't appear to come from the standard military catalogue. According to the Army Times, the aircraft "were a radar-evading variant of the special operations MH-60 Blackhawk." That aircraft has hard edges like those on the F-117 Nighthawk and incorporates similar low-observable technology. The Defense Department has said it will not comment on the aircraft used and, not surprisingly, the Obama Administration has not listed an inventory of equipment used in the attack.