Martin NBS-1 bomber aka MB-2

https://en.wikipedia.org/wiki/Martin_NBS-1

The Martin NBS-1 was a military aircraft of the United States Army Air Service
and its successor, the Air Corps. An improved version of the Martin MB-1, a
scout-bomber built during the final months of World War I, the NBS-1 was ordered
under the designation MB-2 and is often referred to as such. The designation
NBS-1, standing for "Night Bomber-Short Range", was adopted by the Air Service
after the first five of the Martin bombers were delivered.

The NBS-1 became the standard front line bomber of the Air Service in 1920 and
remained so until its replacement in 1928-1929 by the Keystone Aircraft series
of bombers. The basic MB-2 design also was the standard against which
prospective U.S. Army bombers were judged until the production of the Martin
B-10 in 1933.

The NBS-1 was a wood-and-canvas biplane without staggered wings, employing twin
rudders on a twin vertical tail. Its two Liberty 12-A engines sat in nacelles on
the lower wing, flanking the fuselage. Ordered under the company designation
MB-2 in June 1920, the NBS-1 was an improved larger version of the Martin MB-1
bomber built by the Glenn L. Martin Company in 1918, also known as the GMB or
Glenn Martin Bomber. The first flight of the MB-2 took place 3 September 1920.

The NBS-1 was the primary bomber used by Brigadier General Billy Mitchell during
Project B, the demonstration bombing of naval ships in July 1921. Six NBS-1
bombers, led by Captain Walter Lawson of the 96th Squadron operating out of
Langley Field, bombed and sank the captured German battleship SMS Ostfriesland
on 21 July 1921, using specially-developed 2,000 lb (907 kg) demolition bombs
externally mounted beneath the fuselage.

Specifications (NBS-1)

General characteristics
Crew: 4
Length: 42 ft 8 in (13.0 m)
Wingspan: 74 ft 2 in (22.7 m)
Height: 14 ft 8 in (4.8 m)
Wing area: 1,121 ft² (104.2 m²)
Empty weight: 7,232 lb (3,280 kg)
Loaded weight: 12,027 lb (5,460 kg)
Powerplant: 2 × Liberty 12-A liquid-cooled V12 engine, 420 hp (325 kW) each

Performance
Maximum speed: 99 mph (85 kn, 160 km/h)
Cruise speed: 92 mph (80 kn, 150 km/h)
Range: 400 mi (345 nmi, 650 km)
Service ceiling: 7,700 ft (2,350 m)
Rate of climb: 391 ft/min (2.0 m/s)

Armament
Guns: 5× .30 in (7.62 mm) Lewis machine guns
Bombs: 1,800 lb (820 kg) internal; 2,000 lb (907 kg) external


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