Starting with the P-40N-5 (Model 87W), the canopy was redesigned to give the pilot a better field of vision. This variant also reverted to the six gun wing and one rack was added to each wing, these could carry either bombs or drop tanks. A more powerful V-1710-99 engine was introduced on the N-20, and a further improved V-1710-115 was introduced on the N-40. Curtiss attempted to further improve visibility and fitted one P-40N with a bubble canopy; this feature never made it to production.