The Blackbird is a prototype Colonial stealth fighter craft constructed by Chief Petty Officer Galen Tyrol of the Battlestar Galactica - his deck crews, and other members of Galactica. This craft was meant to supplement the Viper, given the issues in maintaining the remaining craft aboard the battlestar. Chief Tyrol had originally intended just to build a standard Viper but ended up building a ship that was of more value to Galactica than another Viper.
The Blackbird is designed to use the Viper launch tubes, and therefore shares the same general shape. It is built more for speed than for maneuverability. The Blackbird is not equipped with any guns, but is equipped with a single missile hardpoint in "Resurrection Ship, Part II".
It does not use metal for its exterior since this metal was reserved for Viper repairs. Instead, on Karl Agathon's suggestion, the Blackbird uses a carbon composite material, which makes it largely invisible to DRADIS scanning.
The Blackbird is FTL-capable, but is not equipped with a Colonial transponder, either for stealth purposes or due to supply shortages.
Along with the usual RCS mechanisms for directional control, the Blackbird is powered by four obsolete DDG-62 engines (designed by Peter Laird, a civilian aeronautical engineer) that came from the flight deck of a Colonial fleet ship named Baah Pakal. One must speculate that since a typical Viper's engines are vulnerable to heat-seeking missiles (Miniseries), these must be as well. This would compromise its stealth features during powered flight. (This is less of a disadvantage in space than in atmospheric flight; a spacecraft's inertia is not disrupted by gravity, friction, and other factors an atmospheric-bound craft would be, and thus can fly straight almost indefinitely without firing its engines while in empty space.)