Culpeper (United States) (AFP) - There was no mistaking the muscular roar of the big radial engine as the most famous trainer to come out of World War II soared above this rural Virginia town. This year marks the 75th anniversary of the North American T-6 Texan, the big tandem-seat warbird in which countless pilots from dozens of countries honed their flying skills. This weekend, some 30 Texans will set off from Culpeper, 70 miles (115 kilometers) outside Washington, and fly up the Potomac River, over the Pentagon and Arlington National Cemetery, to mark a unique aeronautical milestone.