Development
The Keystone XLB-6 prototype was obtained by refitting the final triple-tailed Keystone LB-5 (serial number 27-344) with an LB-5A tail unit; longer (75 foot) straight-chord, untapered and noticeably swept-back wings; and 525 hp (391 kW) Wright Cyclone R-1750-1 radial engines suspended on struts between the wings rather than mounted on the lower wing. This produced a bomber with twice the rate of climb as the LB-5 and slightly faster cruise speed. Production LB-6s featured a five-foot longer fuselage.
The LB-7 used the same extended-span LB-6 airframe powered by Pratt & Whitney Hornet engines.
The remaining variants were ordered before the 1930 change of designators by the United States Army Air Corps from "LB-" (Light bomber) to "B-", but were delivered after the change. Although delivered as bombers, they saw service as cargo and observation aircraft. The LB-10 variant became the basis of the B-3 through B-6 bombers, all of which were used the original LB-6 design, and which served as the primary bombardment force of the Army Air Corps prior to the advent of the monoplane bomber.
Read more about this topic: Keystone LB-6
Famous quotes containing the word development:
“For decades child development experts have erroneously directed parents to sing with one voice, a unison chorus of values, politics, disciplinary and loving styles. But duets have greater harmonic possibilities and are more interesting to listen to, so long as cacophony or dissonance remains at acceptable levels.”
—Kyle D. Pruett (20th century)
“The development of civilization and industry in general has always shown itself so active in the destruction of forests that everything that has been done for their conservation and production is completely insignificant in comparison.”
—Karl Marx (1818–1883)
“I do seriously believe that if we can measure among the States the benefits resulting from the preservation of the Union, the rebellious States have the larger share. It destroyed an institution that was their destruction. It opened the way for a commercial life that, if they will only embrace it and face the light, means to them a development that shall rival the best attainments of the greatest of our States.”
—Benjamin Harrison (1833–1901)