Early P-47 Thunderbolts, (serial number 41-5092), (serial number 41-5930) and an experimental XP-47B, during a test flight. Printed caption on reverse: 'Official photograph US Army Air Forces. NEW THUNDERBOLT FIGHTER FOR US ARMY AIR FORCES. First flight pictures of the US new P-47 fighter plane now in production for the Army Air Forces. This single-seater all-metal high altitude interceptor, popularly known as the Thunderbolt, is powered by a Pratt and Whitney air-cooled radial 18-cylinder 2,00 HP engine. Her gross weight is 13,000 pounds and she carries her heavy armour and strong fire power to 40,000 feet by means of turbo-superchargers. Photo shows: New US Thunderbolt planes in flight formation 19 8 42.'