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Keystone B-5
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<h2 id="design-and-development">Design and development</h2> <p>Three B-3A (LB-10A) were reengined with <a href="/facts/Wright_R-1750-3/oeAoNjAk">Wright R-1750-3</a> radial engines and were redesignated Y1B-5. The Army Air Corps changed the design of the last 27 LB-10As on order, replacing the <a href="/facts/Pratt_%2526_Whitney_R-1690/QCVDyQfA">Pratt & Whitney R-1690</a> 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 <a href="/facts/1934_in_aviation/DHBIVBgu">1934</a>. </p> <h2 id="operational-history">Operational history</h2> <p>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. </p> <h2 id="variants">Variants</h2> LB-14 Designed as <a href="/facts/Keystone_B-3/HsSNGMjT">LB-10</a> with 575 hp (429 kW) <a href="/facts/Pratt_%2526_Whitney_GR-1860/3825CxlT">Pratt & Whitney GR-1860</a> engines; three ordered, but redesigned with 525 hp (392 kW) Wright R-1750-3 engines and delivered as the Y1B-5. Y1B-5 Three pre-production aircraft redesignated from LB-14 before delivery. B-5A Wright R-1750-3 version originally ordered as B-3A, 27 built <h2 id="operators">Operators</h2> <a href="/facts/United_States/P0sCdLe5">United States</a> <ul><li><a href="/facts/United_States_Army_Air_Corps/f5FK5BKQ">United States Army Air Corps</a></li></ul> <h2 id="specifications-b-5a">Specifications (B-5A)</h2> <p>General characteristics </p> <ul><li>Crew: 5</li> <li>Length: 48 ft 10 in (14.9 m)</li> <li>Wingspan: 74 ft 8 in (22.8 m)</li> <li>Height: 15 ft 9 in (4.8 m)</li> <li>Wing area: 1,145 sq ft (106.4 m2)</li> <li>Empty weight: 7,705 lb (3,945 kg)</li> <li>Gross weight: 12,952 lb (5,875 kg)</li> <li>Powerplant: 2 × <a href="/facts/Wright_R-1750/oeAoNjAk">Wright R-1750</a>-3 <a href="/facts/Radial_engine/tS0ljlb7">radial engines</a>, 525 hp (392 kW) each</li></ul> <p>Performance </p> <ul><li>Maximum speed: 111 mph (179 km/h, 97 kn)</li> <li>Cruise speed: 98 mph (160 km/h, 86 kn)</li> <li>Range: 815 mi (1,310 km, 707 nmi)</li> <li>Service ceiling: 14,000 ft (4,270 m)</li> <li>Wing loading: 273.3 lb/sq ft (52.22 kg/m2)</li> <li><a href="/facts/Power-to-weight_ratio/NykmM0pr">Power/mass</a>: 0.0810 hp/lb (133 W/kg)</li></ul> <p>Armament </p> <ul><li>Guns: 3 × .30 in (7.62 mm) <a href="/facts/Browning_Arms_Company/XCKC1NPN">Browning</a> <a href="/facts/Machine_gun/JPXmy1zR">machine guns</a></li> <li>Bombs: 2,500 lb (1,100 kg); 4,000 lb (1,800 kg) on short runs</li></ul> <h2 id="see-also">See also</h2> <p> Related development </p> <ul><li><a href="/facts/Keystone_B-3/HsSNGMjT">Keystone B-3</a></li> <li><a href="/facts/Keystone_B-4/3tkxUJdH">Keystone B-4</a></li> <li><a href="/facts/Keystone_B-6/qp1ovHIj">Keystone B-6</a></li></ul> <p> Related lists </p> <ul><li><a href="/facts/List_of_bomber_aircraft/aAGWSHVe">List of bomber aircraft</a></li> <li><a href="/facts/List_of_military_aircraft_of_the_United_States/jTsQeQdE">List of military aircraft of the United States</a></li></ul> <h2 id="external-links">External links</h2> Wikimedia Commons has media related to Keystone B-5. <ul><li><a href="https://web.archive.org/web/20040804112845/http://www.wpafb.af.mil/museum/research/bombers/b1-47.htm">USAF Museum article on B-5</a></li> <li><a href="https://web.archive.org/web/20040804090325/http://www.wpafb.af.mil/museum/research/bombers/b1-34.htm">USAF Museum article on LB-14</a></li></ul>