The Huff-Daland XHB-1 was an enlarged version of the Huff-Daland LB-1. The aircraft was designed for a 1,200-hp engine, but when the engine ran into developmental problems the Packard 2A-2540 used on the LB-1 was used on XHB-1 also.
The aircraft, unofficially named "Cyclops," was the last single-engine bomber procured by the U.S. Army Air Corps. Army leadership rejected the single-engine bomber for a number of reasons. First, the reliability and survivability in combat of a one engine bomber was questioned. Next, the engine location took up the space normally used by the nose gunner. The XHB-1 had only two fixed .30-caliber machine guns mounted in the wings for forward protection. Finally, the engine also prevented locating the bombardier's compartment in the nose. The XHB-1 had a crew of four: pilot, co-pilot, rear gunner (top) and navigator/rear gunner (bottom). The ventral gunner position had two .30-caliber Lewis machine guns on a flexible mount firing from a retractable platform which was lowered when needed.
The XHB-1 was the only aircraft ever built to carry the Heavy Bombardment designation. Two other designs were assigned HB numbers, but neither was actually constructed.
Armament: Six .30-cal. machine guns and approx. 4,000 lbs. of bombs
Engine: One Packard 2A-2540 of 787 hp Top speed: 109 mph at sea level Span: 84 ft. 7 in. Length: 59 ft. 7 in. Height: 17 ft. 2 in. Weight: 16,834 lbs. gross Crew: Four Serial number: 26-201