01/31/2013. The 23 improved P-40Ds had enough changes to justify the new Curtiss model number 87A-2, and they were delivered to the USAAF under the s/n 40-359 to 40-381 (c/n 13234 to 13256). The 1,150 hp V-1710-39 engine had spur gear reduction that raised the thrust-line and resulted in a new shorter nose design that was retained by all subsequent P-40s.

Nose guns were omitted and two 0.50 in (12.7 mm) caliber guns were installed in each wing, along with provision for two 0.787 in (20 mm) cannon that were never used. Shackles were added under the belly to carry a 52 gal (197 l) auxiliary fuel tank or a 500 lb (227 kg) bomb, and wing bomb rack attachment points were added for six 20 lb (9 kg) bombs as on the XP-40. Fuel tanks were self-sealing and 175 lb (79 kg) of protective armor were used.

Pictured is the first P-40D flown by Curtiss Chief Test Pilot Lloyd Child. Clearly visible here is the short carburetor intake on top of the nose, peculiar to the P-40D and some early P-40Es. Additional photo (site files).