The Keystone bomber

Huff-Daland Airplanes Incorporated was formed in 1920 by Thomas Huff and Elliot Daland, at Ogdensburg, New York. It would become a key early supplier of bombers to the US Army Air Corps, although most would be better known under the Keystone name that was adopted in 1927
The Huff-Daland XHB-1 Cyclops was the only one of the three entries in the Army Air Corps’ Heavy Bomber sequence to actually be produced, and was a modified and expanded version of the Huff-Daland LB-1.
The Huff-Daland XHB-3 was a mid-1920s design for a twin-engine monoplane heavy bomber, and was the final entry in the US Army Air Corps’s short-lived Heavy Bombardment series.
The Huff-Daland LB-1 was the first in a long series of bombers better known as the Keystone bombers (after a change of company name).
The Huff-Daland XLB-3 was one of three attempts to turn the same company’s single engined LB-1 into a twin engined aircraft.
The Huff-Daland XLB-5 was the second attempt to produce a twin-engined version of the company’s LB-1 light bomber, coming between the Huff-Daland XLB-3 and the Keystone XLB-3A.
On 8 March 1927 the new owners of Huff-Daland renamed the company as the Keystone Aircraft Corporation. Over its brief five year existence Keystone would produce nearly 200 bombers for the Army Air Corps, and the Keystone Bomber was the standard American bomber during the early 1930s
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.
The Keystone XLB-3A was the third attempt to produce a twin-engined version of the Huff-Daland LB-1 light bomber.
The Keystone LB-5 was the first of the series of twin-engine biplane bombers developed from the single-engined Huff-Daland LB-1 to enter service with the US Army Air Corps
The Keystone LB-6 was a modified version of the LB-5 twin-engined biplane light bomber, with larger wings, a longer fuselage and new engines.
The Keystone LB-7 was the highest numbered entry in the US Army Air Corps Light Bomber series to enter production, although the 18 aircraft ordered were actually built before the very similar LB-6.
The Keystone LB-8 was the designation given to the seventeenth LB-7 light bomber after it was given Pratt & Whitney R-1860-3 radial engines.
The Keystone LB-9 was the designation given to the last LB-7 after it was re-engined with geared Wright Cyclone
The Keystone LB-10 was the direct predecessor of the Keystone B-3A Panther and the series of biplane bombers that followed, and was the last entry in the LB Light Bomber series to be ordered into productionengines.
The Keystone LB-11 was the designation given to the second-to-last LB-6 while it was being used as an engine test-bed.
The Keystone XLB-12 was the designation given to the first LB-7 light bomber after it had been re-engined with Pratt & Whitney R-1860-1 radial engines.
The Keystone LB-13 was the designation given to seven Keystone bombers that were originally to be powered by geared Pratt & Whitney R-1690-3 radial engines.
The Keystone LB-14 was a short-lived designation given to a version of the LB-10A light bomber that was to be powered by Pratt & Whitney GR-1860 radial engines.
The Keystone B-3A Panther was the fourth version of the Keystone bomber to be produced in significant numbers, and the first to receive a designation in the new B (bombardment) sequence, adopted by the Army Air Corps in 1926.
The Keystone B-4A Panther was ordered alongside the B-6A, and together they were the last biplane bombers to enter American service.
The Keystone B-5A Panther was a twin-engined biplane bomber produced in 1930 by equipping the last 27 B-3A Panthers with Wright engines.
The Keystone B-6A Panther was the final development in a series of bombers descended from the Keystone LB-5, and was the last biplane bomber to enter US Army service.
The Atlantic XHB-2 was a large twin-engine monoplane bomber designed by Antony Fokker’s American subsidiary Atlantic Aircraft.