The Keystone XB-1 Super Cyclops was the first aircraft in the “B” category for US Army bombers, and was an experimental bomber notable for the inclusion of two rear-firing gun positions at the back of the two engine nacelles. It was developed from the earlier Huff-Daland XHB-1 heavy bomber.
The XB-1 was otherwise a standard biplane of the period, with two equal-sized single bay wings and twin rudders. It was designed by the Huff-Daland Company, but by the time it was delivered to the Army this had evolved into Keystone. The XB-1 was powered by a pair of geared Packard 2A-1530 engines, but these were underpowered, and were not accepted by the army. It was then re-engined with two Curtiss V-1570 Conquerors, and was redesignated as the XB-1B.
The XB-1 was much larger than the standard Keystone bomber of the period, which evolved from the LB-5 of 1927 to the B-6A Panther of 1932. From the B-3A onwards these aircraft had a wingspan of 74ft 9in and a length of 48ft 10in, and the heaviest of them – the B-6A had a gross weight of 13,374lb. The XB-1 was ten feet wider, thirteen feet longer and 3,000lb heavier than these aircraft. The standard bomb load of the XB-1 was 2,508lb, compared to 1,995lb for the B-3A.
The XB-1 Super Cyclops was not ordered into production. Instead the Army ordered a small number of Curtiss B-2 Condors, while the lighter Keystone bombers would be the standard Air Corps equipment of the late 1920s and early 1930s.
Engine: Two Curtiss V-1570 Conquerors
Power: 600hp each
Height: 19ft 3in
Empty Weight: 9,462lb
Gross Weight: 16,500lb
Maximum Speed: 120mph
Guns: Six 0.30in Lewis guns
Bomb load: 2,508lb