The Crusader was powered by a Pratt and Whitney J57 turbojet engine. The engine was equipped with an afterburner that, unlike on later engines, was either fully lit, or off (i.e. it did not have "zones"). The engine produced 16,000 lb of thrust static sea level unducted in the initial -44 application, not enough to allow the F-8 to sustain vertical in clean configuration, especially as thrust falls off with installation, subsonic speed, and altitude. The Crusader was the first jet fighter in US service to reach 1,000 mph; U.S. Navy pilot R.W. Windsor reached 1,015 mph on a flight in 1956.