Northrop A-17 USAAC Attack Bomber
Single-engine two-seat low-wing attack bomber monoplane

USAAC Northrop A-17 Attack Bomber
(Northrop Photo, Three-Quarters Front View)

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USAAC Northrop A-17 Attack Bombers

Overview — Northrop A-17 / 8A / Nomad Series

The Northrop A-17 / 8A / Nomad series of attack bombers was a development of the Northrop Gamma 2F. The aircraft was a two-seat single-engine attack bomber monoplane built in 1935 by the Northrop Corporation for the US Army Air Corps.

Development and Design

The Northrop Gamma 2F was an attack bomber derivative of the Northrop Gamma transport aircraft, developed in parallel with the Northrop Gamma 2C, (of which one was built, designated the Northrop YA-13 and Northrop XA-16. The Northrop Gamma 2F had a revised tail, cockpit canopy and wing flaps compared with the Gamma 2C, and was fitted with a new semi-retractable undercarriage. It was delivered to the United States Army Air Corps for tests on 6 October 1934, and after modification, including fitting with a conventional fixed undercarriage, was accepted by the Air Corps. A total of 110 aircraft were ordered as the Northrop A-17 in 1935.

The resulting Northrop A-17 was equipped with perforated flaps, had fixed landing gear with partial fairing. It was fitted with an internal fuselage bomb bay that carried fragmentation bombs and well as external bomb racks. Northrop developed a new undercarriage, this time completely retractable, producing the Northrop 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.

Operational History

The Northrop A-17 entered service in February 1936, and proved to be a reliable and popular aircraft. However, in 1938, the Air Corps decided that attack aircraft should be multi-engine, rendering the Northrop A-17 surplus to requirements. From 14 December 1941, Northrop A-17s were used for coastal patrols by the 59th Bombardment Squadron (Light) on the Pacific side of the Panama Canal.

In June 1940, 93 ex-USAAC aircraft were purchased by France, and refurbished by Douglas, including being given new engines. Not having been delivered before the fall of France, 61 were taken over by the British Purchasing Commission for the RAF and given the name Nomad. They were assessed as being obsolete and sent to South Africa for use as trainers. The remaining 32 aircraft from the French order were transferred to Canada, where they were also used as advanced trainers and target tugs. The last remaining Northrop A-17s, used as utility aircraft, were retired from USAAF service in 1944.

Variants

• Northrop YA-13
• Northrop: XA-16
• Northrop Gamma 2F
• Northrop A-17
• Northrop A-17A
• Northrop A-17AS
• Douglas A-33-DE
• Douglas 8A-1
• Douglas 8A-2
• Douglas 8A-3P
• Douglas 8A-3N
• Douglas 8A-4
• Douglas 8A-5

• Northrop A-17: Initial production for USAAC. Fixed undercarriage, powered by 750-hp (560 kW) Pratt & Whitney R-1535-11 Twin Wasp Jr. engine; 110 built.
• Northrop A-17A: Revised version for USAAC with retractable undercarriage and 825-hp (615 kW) R-1535-13 engine; 129 built.
• Northrop A-17AS: Three seat staff transport version for USAAC. Powered by Pratt & Whitney R-1340 Wasp engine; two built.
• Douglas Model 8A-1: Export version for Sweden. Fixed undercarriage. Two Douglas built prototypes (Swedish designation B.5A), followed by 63 licensed built (by ASJA) B.5B aircraft powered by 920 hp (686 kW) Bristol Mercury XXIV engine; 31 similar B.5C built by SAAB.
• Douglas Model 8A-2: Version for Argentina. Fitted with fixed undercarriage, ventral gun position and powered by 840-hp (626 kW) Wright R-1820-G3 Cyclone; 30 built.
• Douglas Model 8A-3N: Version of A-17A for Netherlands. Powered by 1,100-hp (820 kW) Pratt & Whitney R-1830 Twin Wasp engine; 18 built.
• Douglas Model 8A-3P: Version of A-17A for Peru. Powered by 1,000-hp (746 kW) R-1820 engine; 10 built.
• Douglas Model 8A-4: Version for Iraq, powered by a 1,000-hp (746 kW) R-1820-G103 engine; 15 built.
• Douglas Model 8A-5N: Version for Norway, powered by 1,200-hp (895 kW) R-1830 engine; 36 built. Later impressed into USAAF service as Douglas A-33.

Operators

• Argentina: Argentina purchased 30 Douglas Model 8A-2s in 1937 and received them between February and March 1938. Their serial numbers were between 348 and 377. These aircraft remained in front line service until replaced by the I.Ae. 24 Calquin, continuing in service as trainers and reconnaissance aircraft until their last flight in 1954. The aircraft served with: (1) Grupo A de la Escuela de Aplicación de Aviación based at BAM El Palomar; and (2) Regimiento Aéreo N°3 (Air Regiment No. 3) de Bombardeo Liviano (Light Bombing) based at BAM El Plumerillo
• Canada: The Royal Canadian Air Force received 32 ex-French aircraft serial numbers 3490-3521 and were designated Nomad. All aircraft were assigned to 3rd Training Command.
• France: The French Air Force ordered 93 aircraft but when France fell all of the aircraft were delivered to Great Britain and Canada.
• Iraq: Iraq purchased 15 Douglas Model 8A-4s, in 1940. They were destroyed in the Anglo-Iraqi War in 1941.
• Netherlands: The Netherlands, in urgent need of modern combat aircraft, placed an order for 18 Douglas 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.
• Norway: Norway ordered 36 Douglas Model 8A-5Ns in 1940. These were not ready by the time of the German Invasion of Norway and were diverted to Norwegian Training unit 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.
• Peru: Peru ordered 10 Douglas 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 Douglas Model 8A-5s from Norway, delivered via the United States in 1943. These remained in service until 1958.
• South Africa: The South African Air Force received 57 aircraft from Great Britain designated Nomad I.
• Sweden: Swedish Air Force - Sweden 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 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’.
• United Kingdom: The Royal Air Force received 61 ex-French aircraft redesignated as Nomad I but 57 were handed over to South Africa. British Nomads were serial numbers AS440-AS462, AS958-AS976 and AW420-AW438.
• United States: The United States Army Air Corps received 110 Northrop A-17s and 129 Northrop A-17As. The aircraft were assigned to: (1) 3rd Attack Group based at Barksdale Field; (2) 17th Attack Group based at March Field, (3) 16th Pursuit Group based at Albrook Field 74th Attack Squadron; and (4) General Headquarters Air Force operated three A-17AS aircraft for use as staff transports.

Northrop A-17 USAAC Attack Bomber Specifications and Performance Data

Type

• Primary User: United States Army Air Corps
• Single-engine two-seat low-wing attack monoplane

Wings

• Low-wing cantilever deliver monoplane.
• In three sections, with detachable wings-tips.
• All-metal stressed-skin cellular structure.
• Metal-framed fabric-covered ailerons.
• Split trailing-edge flaps.

Fuselage

• Light alloy monocoque, with smooth stressed skin.

Tail Unit

• Cantilever monoplane type.
• All-metal framework, with stressed-skin covering two fixed services and fabric covering for rudder and elevators.
• Rudder and elevators have inset-hinge balances and trimming-tabs.

Undercarriage

• Fixed cantilever type.
• Single oleo legs and wheels have fairings, with the wheels only partly enclosed.
• Oriental tail-wheel.

Power Plant

• One 750-hp Pratt & Whitney Twin-Wasp Junior radial air-cooled engine.
• Enclosed in a NACA cowling.
• Controllable gills.
• Hamilton-Standard constant-speed airscrew.

Accommodation

• Tandem seats under a transparent canopy.
• Sliding section over pilot’s seat.
• Hinged section over gunner’s cockpit.

Armament

• Five 30-cal. guns, four in the leading-edge of the wing, and one on a flexible mounting in the gunner’s cockpit.
• Provisions for 20 small bombs or four large ones of unspecified weight, or
• An alternative load of chemicals for smoke-screen laying, etc.

Dimensions

• Wingspan: 47 feet 8.5 inches (14.54 m)
• Length: 31 feet 8.7 inches (9.67 m)
• Height: 11 feet 10.5 inches (3.62 m)
• Wing area: 363 ft² (33.8 m²)

Weights and Loadings

• Weight, empty: 4,875 lbs (2,213 kg)
• Weight, loaded: 7,337 lbs (3,328 kg)
• Wing loading: 20.2 lbs/ft² (98.7 kg/m²)
• Power loading: 9.8 lbs/hp (4.4 kg/hp)

Performance

• Maximum speed at S/L: 206 mph (332 km/hr)
• Cruising speed: 170 mph (274 km/hr)
• Rate of climb: 1,530 ft/min (466 m/min)
• Service ceiling: 20,700 feet (6,310 m)
• Absolute ceiling: 22,150 feet (6,786 m)
• Range, normal: 650 miles (1,046 km)
• Range, maximum: 1,240 miles (1,995 km)

References

• Photos: Northrop Exxon Corporation
• Wikipedia: Northrop A-17
• Francillon, René J., McDonnell Douglas Aircraft since 1920: Volume I, Putnam Aeronautical Books, London, 1995, ISBN 0-85177-827-5, pp. 195-208.
• Grey, C.G. and Leonard Bridgman, Jane’s All The World’s Aircraft 1938 (reprint), Arco Publishing Company, New York, 1938, ISBN 0-668-02646-4, p. 286c.
• 1936 Aircraft Year Book
• Allen, Richard Sanders, The Northrop Story 1929-1939, Orion Books, New York, 1990, ISBN 0-517-56677-X, pp. 138-139.