The Huff-Daland XHB-1 (serial number 26-201) was an enlarged and heavier version of the LB-1 single-engined light bomber. It carried a crew of four, with two in an open cockpit ahead of the wing, one near the tail with twin Lewis guns, and the other using a retractable gun platform that could be lowered below the fuselage. Two Browning machine guns were mounted in the wings and over 4000 bombs could be carried. The XHB-1 first appeared in October of 1926. It was to have been powered by a single 1200 hp engine. Since this engine failed to materialize, a single Packard 2A-2540 engine, rated at 787 hp, was substituted. This was the same engine which powered the LB-1. The XHB-1 was known unofficially as the "Cyclops" by the Huff-Daland company.
However, as early as April of 1926, the Army had decided that single-engined bombers were unsatisfactory, concluding that the more conventional twin-engined configuuration was safer and had the additional advantage of allowing for a gunner and/or bomb-aiming position to be mounted in the nose. Consequently, the XHB-1 was not ordered into production, and only one example was built.
Specification of the Keystone XHB-1: One 787 hp Packard 2A-2540 twelve-cylinder Vee liquid-cooled engine. Maximum speed 109 mph at sea level, service ceiling 15,000 feet, range 700 miles with 2508 pound bombload. Weights: 8070 pounds empty, 16,838 pounds gross. Wingspan 84 feet 7 inches, length 59 feet 7 inches, height 17 feet 2 inches, wing area 1648.5 square feet. Armed with two Lewis machine guns in a flexible mount in an open dorsal position. A retractable gun platform could be lowered from the rear fuselage. Two Browning machine guns were mounted in the wings. A bombload of over 4000 pounds could be carried.