Design of the F-105 Thunderchief began in the early 1950s as an internal project at Republic. Intended to be a replacement for the F-84 Thunderjet, the F-105 was created as a supersonic, low-altitude penetrator capable of delivering a nuclear weapon to a target deep within the Soviet Union. Led by Kartveli, the design team produced an aircraft centered on a large engine and able to achieve high speeds. As the F-105 was meant to be a penetrator, maneuverability was sacrificed for speed and low-altitude performance.