Four Pratt & Whitney R-1830-65 Twin Wasp fourteen-cylinder air-cooled radial engines, with General Electric B-22 turbosuperchargers rated at 1200 hp. at 2700 rpm for takeoff and maintaining this power as a military rating up to 31,800 feet.
Maximum speed 300 mph at 30,000 feet, 277 mph at 20,000 feet. Maximum continuous speed 278 mph at 25,000 feet. Usual combat operating speed was 180 - 215 mph at between 10,000 and 25,000 feet. Initial climb rate 1,025 feet per minute. At a takeoff weight of 56,000 pounds, an altitude of 20,000 feet could be reached in 25 minutes. Service ceiling 28,000 feet at 56,000 pound takeoff weight. Range and endurance with a 5,000 pound bombload was 1700 miles in 7.3 hours at 25,000 feet (all-up weight of 61,000 pounds) with 2,364 US gallons of fuel. Landing speed 95 mph (light), 125 mph (loaded).
38,000 pounds empty, 56,000 pounds combat, 71,000 pounds maximum overload. 2,364 US gallons of fuel in main tanks, plus 450 gallons in auxiliary wing tanks and 800 gallons in extra tanks fitted in bomb bay if required.
Wingspan 110 feet 0 inches, length 64 feet 2 inches, height 18 feet 0 inches, wing area 1048 square feet.
Crew was normally ten (pilot, copilot, bombardier, nose gunner, navigator, radio operator, ball turret gunner, two waist gunners, and tail gunner).
Ten 0.50 -inch Browning machine guns in nose, upper ventral, and tail turrets and in waist positions. Maximum internal bomb load was 8,000 pounds. Two 4,000 pound bombs could be carried on external racks, one underneath each wing. Maximum short range bomb load was 12,800 pounds (by using underwing racks) but normal offensive load was 5,000 pounds.