Martin MB-1

Martin MB-1
Martin MB-1 GMB, 1936
Role	Large biplane bomber
Manufacturer	Glenn L. Martin Company
Designer	Donald Wills Douglas, Sr.[1]
First flight	1918
Introduction	1918
Primary users	United States Army Air Service United States Navy United States Marine Corps United States Postal Service
Number built	20[2]

The Martin MB-1 was a 1910s American large biplane bomber designed and built by the Glenn L. Martin Company for the United States Army Air Service. It was the first purpose-built bomber produced by the United States.

In 1921 Martin produced its KG.1 variant of the MB-1, with 10 purchased by the Navy as a torpedo bomber under the designation MBT. After two were purchased, the designation was changed to Martin MT.

Development

In response to a requirement from the Air Service for a bomber that was superior to the Handley Page O/400. Martin proposed the MB-1 and were rewarded with an initial production contract for six aircraft. The MB-1 was a conventional biplane design with twin fins and rudders mounted above the tailplane and a fixed tailwheel landing gear with four-wheel main gear. Powered by two 400 hp (298 kW) Liberty 12A engines. It had room for a crew of three in open cockpits.

Operational history

Initial delivery to the Air Service was in October 1918, with the aircraft designated GMB for Glenn Martin Bomber. The first four produced were configured as observation aircraft, and the next two as bombers. Four others were produced before the end of World War I cancelled all remaining war contracts. The last three aircraft each were configured experimentally, with separate designations: GMT (Glenn Martin Transcontinental), a long range version with a 1,500 mi (2,400 km) range; GMC (Glen Martin Cannon) with a nose-mounted 37 mm (1.46 in) cannon; and GMP (Glenn Martin Passenger) as an enclosed 10-passenger transport. The GMP was later re-designated T-1. Six surviving aircraft were later modified and used by the United States Postal Service as mail carriers. The design was the basis the Martin MB-2, which had a greater load capability but was slower and less maneuverable.

Ten aircraft were used by the United States Navy from 1922 under the designations MBT and MT and were used as torpedo bombers, two by the Navy and eight by Marine Corps squadron VF-2M.

Variants

MB-1

Company and original military designation.

GMB

Glenn Martin Bomber - Air Service designation for the MB-1 aircraft.

GMT

Glenn Martin Transcontinental - designation for one aircraft with long range fuel tanks.

GMC

Glenn Martin Cannon - designation for one cannon equipped aircraft.

GMP

Glenn Martin Passenger - designation for one 10-seat passenger variant, later designated T-1

MBT

Martin Bomber-Torpedo - United States Navy/Marine Corps torpedo-bomber variant, two built.

MT

Martin Torpedo - United States Navy/Marine Corps version with an MB-1 fuselage and MB-2 wings, eight built, later designated the TM-1

T-1

GMP re-designated.

TM-1

MT re-designated.

Operators

 United States

• United States Army Air Service
• United States Marine Corps
• United States Navy
• United States Postal Service

Specifications

Data from United States Military Aircraft since 1909 ^[3]

General characteristics

• Crew: 3 (pilot, bombardier, gunner)
• Length: 44 ft 10 in (13.67 m)
• Wingspan: 71 ft 5 in (21.77 m)
• Height: 14 ft 7 in (4.45 m)
• Wing area: 1,070 ft² (99.4 m²)
• Empty weight: 6,702 lb (3,040 kg)
• Gross weight: 10,225 lb (4,638 kg)
• Powerplant: 2 × Liberty 12A liquid-cooled Vee, 400 hp (298 kW) each each

Performance

• Maximum speed: 105 mph (169 km/h)
• Cruise speed: 92 mph (148 km/h)
• Range: 390 miles (628 km)
• Service ceiling: 10,300 ft (3,100 m)
• Rate of climb: 630 ft/min (3.2 m/s)

Armament

• Five .30-cal. machine guns
• 1,040 lb of bombs

References

Notes

1. ^ Yenne. The Pictorial History of American Aircraft. 
2. ^ Confusion over Air Service serial numbers has led to figures sometimes seen of 22 or more. However six were built on the first contract, and a later four built in 1919 before the end of the war cancelled all remaining ordered. Ten more were produced for the USN/USMC.
3. ^ Swanborough and Bowers 1963, p. 327.

Bibliography

• The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). London: Orbis Publishing, 1985, p. 2419.
• Andrade, John. U.S. Military Aircraft Designations and Serials since 1909. Hinckley, UK: Midland Counties Publications, 1979. ISBN 0-904597-22-9.
• Swanborough, F.G and Peter M. Bowers. United States Military Aircraft since 1909. London: Putnam, 1963.
• Taylor, Michael J. H. Jane's Encyclopedia of Aviation. London: Studio Editions, 1989. ISBN 0-51710-316-8.