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Keystone B-5A
Role Light bomber
Manufacturer Keystone Aircraft
Primary user United States Army Air Corps
Number built 3 Y1B-5
27 B-5A
Developed from Keystone B-3

The Keystone B-5 was a light bomber made for the United States Army Air Corps in the early 1930s. The B-5A was a Keystone B-3A with Wright Cyclone rather than Pratt & Whitney engines.

Design and developmentEdit

Three B-3A (LB-10A) were reengined with Wright R-1750-3 radial engines and were redesignated Y1B-5. The Army Air Corps changed the design of the last 27 LB-10As on order, replacing the Pratt & Whitney R-1690 radial engines with the Wright R-1750-3. The Pratt & Whitney-powered aircraft were designated B-3A, and the Wright-powered aircraft became B-5A. They provided the backbone of the U.S. bomber force from then to 1934.

Operational historyEdit

B-5A were first line bombers of the United States for the period between 1930 and 1934. Afterwards, they remained in service primarily as observation aircraft until the early 1940s.


As LB-10 with 575 hp (429 kW) Pratt & Whitney GR-1860 engines but delivered as the Y1B-5.
Three pre-production aircraft redesignated from LB-14 before delivery.
Wright R-1750-3 version originally ordered as B-3A, 27 built


US flag 48 stars.svg United States

Specifications (B-5A)Edit

General characteristics

  • Crew: 5
  • Length: 48 ft 10 in (14.9 m)
  • Wingspan: 74 ft 8 in (22.8 m)
  • Height: 15 ft 9 in (4.8 m)
  • Wing area: 1,145 ft² (106.4 m²)
  • Empty weight: 7,705 lb (3,945 kg)
  • Loaded weight: 12,952 lb (5,875 kg)
  • Max. takeoff weight: lb (kg)
  • Powerplant: 2 × Wright R-1750-3 radial engines, 525 hp (392 kW) each


  • Maximum speed: 111 mph (97 kn, 179 km/h)
  • Cruise speed: 98 mph (86 kn, 160 km/h)
  • Range: 815 mi (707 nmi, 1,310 km)
  • Service ceiling: 14,000 ft (4,270 m)
  • Wing loading: 273.3 lb/f² (52.22 kg/m²)
  • Power/mass: 0.0810 hp/lb (133 W/kg)</ul>Armament
  • Guns: 3 × .30 in (7.62 mm) Browning machine guns
  • Bombs: 2,500 lb (1,100 kg); 4,000 lb (1,800 kg) on short runs

See alsoEdit

External linksEdit

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