The Curtiss B-2 Condor was a twin engined bomber produced in the late 1920s and that was the last bomber produced for the US Army by Curtiss and was a development of the Curtiss-Martin NBS-1.
The NBS-1 had been designed by Martin, and was a three bay equal span biplane, powered by two Liberty engines and with a fabric covered wooden framework for the fuselage and wings. Martin had produced 20 as the MB-2, but Curtiss had produced fifty of a follow-up order of 110, and had then been given the contract to produce two prototypes of an improved version. The Curtiss NBS-4 of 1922 had a welded steel tube framework and a biplane tail, but was otherwise similar to the NBS-1. One of these aircraft was later modified to carry two machine guns in cockpits carried at the rear end of the nacelles.
Work then moved onto the B-2 Condor. This was similar to the NBS-4, but with the nacelle gunners positions of the modified prototype. It was a three bay equal span biplane, with a welded steel fuselage. The wings saw the main change and had welded steel tube wing spars and riveted duralumin ribs. The engines were also changed, from the wartime Liberty to Curtiss's new V-1570 Conqueror engine. The engine radiators were mounted vertically above the engines. The crew rose from four to five - two wing gunners, the nose gunner, pilot and co-pilot. It kept the biplane tail of the NBS-4.
A single XB-2 prototype was ordered in 1926. It made its maiden flight in July 1927, but was lost in December after only 59 hours in the air. The Curtiss XB-2 was in competition with the Keystone XB-1, but although it was a superior aircraft it was also more expensive. The Army ordered two B-2 Condors in 1928 and another ten in 1929, but they would be the last bombers Curtiss designed for the army's B for Bomber sequence. Keystone received the bulk of the production orders, and produced nearly 200 aircraft of several different types in 1927-32.
One B-2 was used to test an automatic pilot system in 1930. Another was given dual controls and was redesignated as the B-2A.
The production B-2s were delivered from June 1928, and went to the 11th Bombardment Squadron, then the only heavy bomber squadron in the USAAC. They had a limited service although the last was still in use as late as July 1936. During their service career they took part in the annual air exercises and were used as mail planes.
The B-2 was also developed into a civil airliner. The Army gave permission for this development in 1928, and the first of the new aircraft made its maiden flight in June 1929. The civil B-2 was an eighteen seat passenger aircraft, called the Condor 18.
Six Condor 18s were built in two batches of three. The first three were very similar to the standard B-2, but with three rows of seats in the fuselage and an enclosed pilot's cockpit. The airliner actually used the same nacelles as the B-2 bomber, although the gun positions were faired over. The second three saw further development, with a number of detailed changes. The Condor 18 wasn't a commercial success, as the market had already been taken by Ford and Fokker three engined aircraft. The six aircraft were sold to Eastern Air Transport in 1931-32, but were all retired in 1934.
Engine: Two Curtiss GV-1570 piston engines
Power: 600hp each
Span: 90ft 0in
Length: 47ft 4.5in
Height: 16ft 3in
Empty weight: 9,300lb (equipped)
Maximum take-off weight: 16,591lb
Max speed: 132mph
Service ceiling: 17,100ft
Endurance: 805 miles
Armament: Six 0.3in machine guns
Bomb load: 2,508lb