The Hornet NF.21 was designed to fill a need for a naval night fighter. Special flame-dampening exhausts were installed, and a second basic cockpit was added to the rear fuselage, just above the wing trailing edges. ASH radar equipment was placed in the rear of this cockpit, with the radar operator/navigator seated facing aft. To gain access, a small trapdoor was provided in the lower fuselage; a fixed, teardrop-shaped bubble canopy, which could be jettisoned in an emergency, provided a good field of view. At the front of the aircraft, the nose underwent a transformation with the small rotating ASH radar dish being housed under an elongated "thimble" radome. The horizontal tail units were increased in span. The effect of these modifications on performance was minimal; about 4 mph (6 km/h).