The Keystone LB-6 was an improved version of the XLB-6, which was in turn an improved version of the LB-5. The major design changes in the LB-6 were a lengthened fuselage and a modified tail unit. Eighteen aircraft were ordered after the U.S. Army selected it over the Curtiss XB-2 although the first aircraft (S/N 29-10) was diverted for test purposes and became the XLB-9 (and later reconverted to the LB-6 configuration).
TECHNICAL NOTES: Armament: Five .30-cal. machine guns and 2,000 lbs. of bombs Engines: Two Wright R-1750-1 radials of 525 hp each Top speed: 114 mph at sea level Cruising speed: 95 mph Service ceiling: 11,650 ft. Range: 632 miles with full bomb load Span: 75 ft. 0 in. Length: 49 ft. 3 in. Height: 18 ft. 1 in. Weight: 13,440 lbs. gross Crew: Five Serial numbers: 29-11 to 29-27