Martin XB-33 Super Marauder

XB-33 Super Marauder
Role	Medium bomber
National origin	United States
Manufacturer	Glenn L. Martin Company
Status	Cancelled 25 November 1942
Primary user	United States Army Air Forces
Number built	None
Developed from	B-26 Marauder

The Martin B-33 was designed by the Glenn L. Martin Company as the Martin Model 190 and was a high-altitude derivative of the company's B-26 Marauder. Two different designs were developed, first as a twin-engined aircraft and then as a four-engined aircraft. The four-engined version was ordered by the United States Army Air Forces but the program was cancelled before any aircraft were built.

Design and development

XB-33

Schematic blueprint drawing of the XB-33.

The first version of the B-33 design, the XB-33, was a twin-tailed medium bomber with two Wright R-3350 engines and pressurised crew compartments; its design began in 1940. It would carry around 4,000 lb (1,814 kg) of bombs. Soon after design of the XB-33 began it became clear that a twin-engined aircraft would not achieve the performance requested by the army. The company moved on to developing a larger four-engined design and the two prototypes ordered by the USAAF were not built.

XB-33A

Following the abandoment of the original twin-engined design the company continued to design a larger four-engined design and two prototypes were ordered by the USAAF as the XB-33A; its bombload was to have been 12,000 lb (5,443 kg), as much as that of the B-24 Liberator, the heaviest US bomber flown in combat prior to the B-29.

The original XB-33 design was to be powered by the R-3350, the redesigned XB-33A was to use Wright R-2600 engines. The main reason for this was demand for R-3350s for the B-29, one of the most highly valued projects of the Army Air Forces.

On January 17, 1942, the USAAF placed an order for 400 B-33As to be built at the government-owned plant in Omaha, Nebraska operated by Martin. On November 25, 1942 the project was cancelled to allow the Omaha plant to concentrate on manufacturing B-29s.

Variants

XB-33

Prototype medium bomber powered by two 1,800 hp (1,343 kW) R-3350 engines, two cancelled.^[1]

XB-33A

Prototype medium bomber powered by four 1,800 hp (1,343 kW) R-2600-15 engines, two cancelled.^[1]

B-33A Super Marauder

Production variant of XB-33A, 400 on order cancelled.^[1]

Specifications (B-33A, as designed)

General characteristics

• Crew: 7
• Length: 79 ft 10 in (24.3 m)
• Wingspan: 134 ft (40.8 m)
• Height: 24 ft (7.32 m)
• Wing area: 1,646 ft² (153 m²)
• Empty weight: 85,000 lb (39,000 kg)
• Loaded weight: 95,000 lb (43,000 kg)
• Powerplant: 4 × Wright R-2600-15 radial engines, 1,800 hp (1,300 kW each) each

Performance (estimated)

• Maximum speed: 345 mph (300 kn, 555 km/h)
• Cruise speed: 242 mph (210 kn, 389 km/h)
• Range: 2,000 mi (1,700 nmi, 3,000 km)
• Service ceiling: 39,000 ft (12,000 m)
• Rate of climb: ft/min (m/s)
• Wing loading: 58 lb/ft² (280 kg/m²)
• Power/mass: 0.076 hp/lb (55 W/kg)

Armament

• Guns: 8× .50 in (12.7 mm) machine guns
• Bombs: 10,000 lb (4,500 kg)

See also

Related development

• B-26 Marauder
  

Related lists

• List of military aircraft of the United States
• List of bomber aircraft
  

References

1. ^ ^{a b c} Andrade 1979, p 51

• Encyclopedia of American Aircraft
• Andrade, John (1979). U.S.Military Aircraft Designations and Serials since 1909. Midland Counties Publications. ISBN ISBN 0-904597-22-9.