Data from 
General characteristics
Crew: Six to eight
Length: 61 ft 9 in (18.82 m)
Wingspan: 95 ft 0 in (28.96 m)
Height: 14 ft 9 in (4.50 m)
Wing area: 1,120 sq ft (104 m²)
Empty weight: 19,082 lb (8,655 kg)
Gross weight: 27,253 lb (12,362 kg)
Max takeoff weight: 40,000 lb (18,144 kg)
Powerplant: 2 × Pratt & Whitney R-2180-A Twin Hornet turbosupercharged radial engines, 1,200 hp (890 kW)  each
Propellers: 3-bladed
Performance
Maximum speed: 220 mph (350 km/h, 190 kn) at 10,000 feet (3,000 m)
Cruise speed: 190 mph (310 km/h, 170 kn)
Range: 1,960 mi (3,150 km, 1,700 nmi) with 2,200 pounds (1,000 kg) of bombs
Combat range: 600 mi (970 km, 520 nmi) with 10,000 pounds (4,500 kg) of bombs
Service ceiling: 25,000 ft (7,600 m)
Time to altitude: 10 minutes to 10,000 feet (3,000 m)
Armament
Guns: Five .30-calibre machine guns, mounted in single turrets in the nose and dorsal positions, and single manually operated mounts in the waist and ventral positions.

Bombs: Up to 10,000 pounds (4,500 kg) in an internal bay.
Data from 
General characteristics
Crew: Six to eight
Length: 61 ft 9 in (18.82 m)
Wingspan: 95 ft 0 in (28.96 m)
Height: 14 ft 9 in (4.50 m)
Wing area: 1,120 sq ft (104 m²)
Empty weight: 19,082 lb (8,655 kg)
Gross weight: 27,253 lb (12,362 kg)
Max takeoff weight: 40,000 lb (18,144 kg)
Powerplant: 2 × Pratt & Whitney R-2180-A Twin Hornet turbosupercharged radial engines, 1,200 hp (890 kW)  each
Propellers: 3-bladed
Performance
Maximum speed: 220 mph (350 km/h, 190 kn) at 10,000 feet (3,000 m)
Cruise speed: 190 mph (310 km/h, 170 kn)
Range: 1,960 mi (3,150 km, 1,700 nmi) with 2,200 pounds (1,000 kg) of bombs
Combat range: 600 mi (970 km, 520 nmi) with 10,000 pounds (4,500 kg) of bombs
Service ceiling: 25,000 ft (7,600 m)
Time to altitude: 10 minutes to 10,000 feet (3,000 m)
Armament
Guns: Five .30-calibre machine guns, mounted in single turrets in the nose and dorsal positions, and single manually operated mounts in the waist and ventral positions.
Bombs: Up to 10,000 pounds (4,500 kg) in an internal bay.
North American XB-21