The Gamma 2F had a revised tail, cockpit canopy and wing flaps compared with the Gamma 2C, and was fitted with new semi-retractable landing gear. It was delivered to the United States Army Air Corps for tests on 6 October 1934, and after modifications which included fitting with a conventional fixed landing gear, was accepted by the Air Corps. A total of 110 aircraft were ordered as the A-17 in 1935.
The resulting A-17 was equipped with perforated flaps, and had fixed landing gear with partial fairings. It was fitted with an internal fuselage bomb bay that carried fragmentation bombs and well as external bomb racks.
Northrop developed a new landing gear, this time completely retractable, producing the A-17A variant. This version was again purchased by the Army Air Corps, who placed orders for 129 aircraft. By the time these were delivered, the Northrop Corporation had been taken over by Douglas Aircraft Company, export models being known as the Douglas Model 8.
The A-17 entered service in February 1936, and proved a reliable and popular aircraft. However, in 1938, the Air Corps decided that attack aircraft should be multi-engined, rendering the A-17 surplus to requirements.
From 14 December 1941, A-17s were used for coastal patrols by the 59th Bombardment Squadron (Light) on the Pacific side of the Panama Canal.
The last remaining A-17s, used as utility aircraft, were retired from USAAF service in 1944.
Argentina purchased 30 Model 8A-2s in 1937 and received them between February and March 1938. Their serial numbers were between 348 and 377. These remained in frontline service until replaced by the I.Ae. 24 Calquin, continuing in service as trainers and reconnaissance aircraft until their last flight in 1954.
Peru ordered ten Model 8A-3Ps, these being delivered from 1938 onwards. These aircraft were used in combat by Peru in the Ecuadorian-Peruvian war of July 1941.
The survivors of these aircraft were supplemented by 13 Model 8A-5s from Norway (see below), delivered via the United States in 1943 (designated A-33). These remained in service until 1958.
The Swedish government purchased a licence for production of a Mercury-powered version, building 63 B 5Bs and 31 B 5Cs, production taking place from 1938 to 1941. They were replaced in service with the Swedish Air Force by SAAB 17s from 1944.
The Swedish version was used as a dive bomber and as such it featured prominently in the 1941 film Första Divisionen (sv).
The Netherlands, in urgent need of modern combat aircraft, placed an order for 18 Model 8A-3Ns in 1939, with all being delivered by the end of the year. Used in a fighter role for which they were unsuited, the majority were destroyed by Luftwaffe attacks on 10 May 1940, the first day of the German invasion.
Iraq purchased 15 Model 8A-4s, in 1940. They were destroyed in the Anglo-Iraqi War in 1941.
Main article: Douglas A-33
Norway ordered 36 Model 8A-5Ns in 1940. These were not ready by the time of the German Invasion of Norway and were diverted to the Norwegian training camp in Canada, which became known as Little Norway.
Norway decided to sell 18 of these aircraft as surplus to Peru, but these were embargoed by the United States, who requisitioned the aircraft, using them as trainers, designating them the A-33.
Norway sold their surviving aircraft to Peru in 1943.
In June 1940, 93 ex-USAAC aircraft were purchased by France, and refurbished by Douglas, including being given new engines. These were not delivered before the fall of France and 61 were taken over by the British Purchasing Commission for the British Commonwealth use under the name Northrop Nomad Mk I.
The RAF assessed the Northrop Nomad Mk Is as "obsolete" and sent them to South Africa for use as trainers, serialed AS440 to AS462, AS958 to AS976 and AW420 to AW438.
The Royal Canadian Air Force received 32 Nomads that had been part of a French order of 93 aircraft. When France fell in 1940, this order was taken over by Great Britain who transferred 32 of the aircraft to Canada where they were used as advanced trainers and target tugs as part of the British Commonwealth Air Training Plan. These were serialed 3490 to 3521; all were assigned to No. 3 Training Command RCAF.
Crew: two pilot and gunner
Length: 9.67 m
Wingspan: 14.54 m
Height: 3.62 m
Wing area: 33.7m²
Empty weight: 2,211 kg
Loaded weight: 3,328 kg
Powerplant: 1 × Pratt & Whitney R-1535-11 Twin Wasp Jr two-row air-cooled radial engine, 750 hp (560 kW)
Maximum speed: 332 km/h
Cruise speed: 274 km/h
Range: 1,046 km
Service ceiling: 5,915 m
Rate of climb: 6.9 m/s
Armament 4 × 7.62 mm forward Browning mg+ 1 × 7.62 mm rear mg
Internal bay for bombs
External wing bomb racks 544 kg)