XB-38 Flying Fortress

The XB-38 Flying Fortress was a prototype US bomber aircraft of World War II. It was the result of a modification project undertaken by Boeing and Lockheed on a B-17 Flying Fortress to fit it with Allison V-1710-89 engines. It was meant as an improved version of the B-17, and a variant that could be used if the Wright R-1820 engine became scarce. Completing the modifications took less than a year, and the XB-38 made its first flight on May 19 1943.

While it showed a slightly higher top speed, after a few flights it had to be grounded due to a problem with engine manifold joints leaking exhaust. Following the fixing of this problem, testing continued until the ninth flight on June 16 1943. During this flight, the third (right inboard) engine caught fire, and the crew was forced to bail out. The XB-38 was destroyed and the project cancelled, in part because the V-1710 engines were needed for other projects, especially the vital P-38 Lightning and P-40 Warhawk fighters.

Specifications

General Characteristics

• Crew: 10
• Length: 74 ft 4 in (22.7 m)
• Wingspan: 103 ft 10 in (31.6 m)
• Height: 19 ft 1 in (5.8 m)
• Wing area: 1527 ft² (141.9 m²)
• Empty: 54,900 lb (24,900 kg)
• Loaded: 62,134 lb (28,183 kg)
• Maximum takeoff: 64,000 lb (29,000 kg)
• Powerplant: 4× Allison V-1710-97 turbo-supercharged radials, 1,200 hp (895 kW)

Performance

• Maximum speed: 327 mph (526 km/h)
• Cruise speed: 226 mph (364 km/h)
• Range: 1,900 miles (3,100 km)
• Service ceiling: 36,600 ft (11,200 m)
• Rate of climb: ft/min ( m/min)
• Wing loading: 47.2 lb/ft² (231 kg/m²)
• Power/Mass: .0655 hp/lb (.110 kW/kg)

Armament

• 13× .50 Browning M2 machine guns
• 6,000 lb (2,700 kg) of bombs

Links

• USAF Museum article on XB-38

Related Content

Related development: B-17 Flying Fortress - YB-40 Flying Fortress

Comparable aircraft: XB-39 Superfortress

Designation sequence: YB-35 - B-36 - B-37 - XB-38 - XB-39 - YB-40 - XB-41