Northrop 5A<

Northrop 5B
single-engine two-seat low-wing monoplane

Archive Photos

Northrop 5B, (Gamma 5B, NR14998, NX14998, XA-ABI, c/n 188) (Northrop photo)

Overview — Northrop Gamma Series

The Northrop Gamma was a single-engine all-metal monoplane cargo aircraft used in the 1930s. Towards the end of its service life, it was developed into a light bomber.

Design and Development — The Northrop Gamma was a further development of the successful Northrop Alpha and shared its predecessor’s aerodynamic innovations with wing fillets and multicellular stressed-skin wing construction. Like late Northrop Alphas, the fixed landing gear was covered in distinctive aerodynamic spats, and the aircraft introduced a fully enclosed cockpit.

Operational History — The Northrop Gamma saw fairly limited civilian service as mail planes with Trans World Airlines, but had an illustrious career as flying laboratory and record-breaking aircraft. The US military found the design sufficiently interesting to encourage Northrop to develop it into what eventually became the Northrop A-17 Nomad light attack aircraft. Military versions of the Northrop Gamma saw combat with Chinese and Spanish Republican air forces. Twenty Five Northrop Gamma 2Es were assembled in China from components provided by Northrop.

On June 2, 1933 Frank Hawks flew his Northrop Gamma 2A Texaco Sky Chief from Los Angeles to New York in a record 13 hours, 26 minutes, and 15 seconds. In 1935, Howard Hughes improved on this time in his modified Northrop Gamma 2G making the west-east transcontinental run in 9 hours, 26 minutes, and 10 seconds.

The most famous Northrop Gamma was the Northrop Gamma 2B Polar Star. The aircraft was carried via ship and off-loaded onto the pack ice in the Ross Sea during Lincoln Ellsworth’s 1934 expedition to Antarctica. The Northrop Gamma 2B was almost lost when the ice underneath it broke and it had to be returned to United States for repairs. The Northrop Gamma 2B Polar Star’s second return to Antarctica in September 1934 was also futile — a connecting rod broke and the aircraft had to be returned yet again for repairs. On January 3, 1935, Ellsworth and pilot Bernt Balchen finally flew over Antarctica.

On November 23, 1935, Ellsworth and Canadian pilot Herbert Hollick-Kenyon attempted the world’s first trans-Antarctic flight from Dundee Island in the Weddell Sea to Little America. The crew made four stops during their journey, in the process becoming the first people ever to visit Western Antarctica. During one stop, a blizzard completely packed the fuselage with snow which took a day to clear out. On December 5, after traveling over 2,400 miles (3,865 km) the aircraft ran out of fuel just 25 miles (40 km) short of the goal. The intrepid crew took six days to travel the remainder of the journey and stayed in the abandoned Richard E. Byrd camp until being found by the Discovery II research vessel on January 15, 1936. The Northrop Gamma 2B Polar Star was later recovered and donated to the Smithsonian National Air and Space Museum where it resides to this day.

Overview — Northrop 5B

The Northrop 5s (Northrop Gamma 5s) were three attack bombers that were designed in parallel with the Air Corps A-17 Nomad series. Intended for export markets, the three Northrop 5 experimental aircraft (5A, 5B and 5D) closely corresponded to the various models in the progressive development of the attack bombers being produced for the U.S. Army.

Northrop 5A

The first of these aircraft, the Northrop 5A, was a single-engine two-seat low-wing monoplane. The aircraft closely resembled the Northrop YA-13 from which it differed in being powered by 775-hp Wright R-1820F-52 driving a three-blade propeller. The canopy was also shallower than that of the YA-13. Manufactured in October 1935, the Northrop 5A (c/n 187) was approved for X license (NX14997) 4 October 1935 and registered to the Northrop Corporation, Inglewood, CA. A month later, after completing its manufacturer’s trials at Mines Field (now LAX), the aircraft was shipped to Japan with no export certificate or bill of sale. The customer was the Japanese Navy, and the airplane was used for a study of modern aviation engineering. The aircraft was coded BXN1 by the Japanese Navy and given flight evaluation. It was destroyed in an accident during tests.

Northrop 5B

The second of these aircraft, the Northrop 5B, was a two-place closed-cabin monoplane with sliding cockpits forward and a slim rear fuselage. The aircraft retained the trousered undercarriage of the Northrop YA-13 and 5A, but was initially powered by 700-hp Pratt & Whitney Twin Wasp, Jr. SA1-G (#235) fitted into a longer chord cowling and driving a three-blade propeller. The aircraft was manufactured in October 1935 (Gamma 5B, c/n 188) and was approved 11/2/1935 for R license (NR14998) to the Northrop Corporation, Inglewood, CA, with the intent to make a goodwill foreign tour.

The Northrop 5B was issued an X license (NX14998) on 6/15/1936 and an engine change to a 775-hp Wright Cyclone R-1820F-52 (#23403). At that time, the aircraft had a TT 26 hrs and had been in storage with wing and propeller unassembled. The aircraft arrived in Buenos Aires, Argentina, September 1936, and was demonstrated over a three month period to the Fuerza Aérea Argentina by pilot Edmund T. Allen. The aircraft was reapproved for an X license (NX14998) at Buenos Aires with a Wright Cyclone G engine (#23236) with a TT 126 hrs.

In February 1937, a ferry permit was issued for Buenos Aires—Mexico City flight for sale to Lt. Col. Montero. The aircraft was sold c. 3/1/1937 to Henry G. Fletcher, Mexico City, Mexico and registered as XA-ABI. The aircraft was reported to have been flown to Mexico City—Vera Cruz on 3/17/1937 and stored in the Pan Am hangar. In actuality, the aircraft was bought by agents of the Spanish Republic and was shipped on S.S. Ibai on 12/26/1937 to Bordeaux with an ultimate destination of the Spanish Republican Air Force. The aircraft was flown on coastal patrols. The disposition of the aircraft is unknown.

Northrop 5D

The third of these aircraft, the Northrop 5D (s/n 291, X16091) was completed in August 1936 and corresponded closely to the Northrop A-17AS. Like the Northrop A-17AS, the Northrop 5D was fitted with a retractable main undercarriage and was powered by a 600-hp Pratt & Whitney S3H-1 (#6153) nine-cylinder radial engine driving a two-blade propeller. The aircraft was approved for X license (NX16091) on 9/15/1936 to the Northrop Corporation, Inglewood, CA. The tail surfaces and interior were listed as Army type upon the inspection report. With no ATC, export certificate, or bill of sale record, the aircraft was exported September 1936 to Japan. The customer was the Japanese Navy, and coded the aircraft BXN2. After Japanese Navy flight testing, the aircraft was handed over to the Nakajima Aircraft Manufacturing Company at Koizumi, Japan, for study by engineers. It is said that the aircraft was very helpful in the design and construction of aircraft which led to the Type 97 carrier-based attack bomber, or Nakajima Kate. The aircraft was passed on to Manchurian Air Lines, whose photographic division used it for aerial reconnaissance, both over China and above USSR territory through 1939.

Northrop Gamma Variants

Civil Variants

Northrop Gamma 1E: Single-engine (Pratt & Whitney Hornet) two-seat closed-cabin low-wing land monoplane, 1 built, Sweden A.B Aerotransport, c/n 29.
Northrop Gamma 2A: Single-engine (Wright Whirlwind) single-seat closed-cabin low-wing land monoplane, 1 built, Texaco Sky Chief, c/n 1.
Northrop Gamma 2B: Single-engine (Pratt & Whitney Wasp) two-seat closed-cabin low-wing land monoplane, 1 built, Ellsworth Polar Star, c/n 2.
Northrop Gamma 2C: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft YA-13, c/n 5.
Northrop Gamma 2D: Single-engine (Wright Cyclone) single-seat closed-cabin low-wing land monoplane, 3 built, TWA cargo aircraft, c/n 8-10.
Northrop Gamma 2E: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 14, c/n 46, c/n 48-72.
Northrop Gamma 2EC: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 17-22, c/n 45.
Northrop Gamma 2ED: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, light attack bomber, Chinese Military, c/n 15-16, c/n 23-27, c/n 30-37.
Northrop Gamma 2ED-C: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, shipped to USSR, c/n 47.
Northrop Gamma 2F: Single-engine (Pratt & Whitney R-1870-7) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft XA-16, c/n 5.
Northrop Gamma 2G: Single-engine (Curtiss Conqueror) two-seat closed-cabin low-wing racing land monoplane, 1 built, Jacqueline Cochran, c/n 11.
Northrop Gamma 2H: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing racing land monoplane, 1 built for Marron Price Guggengeim, flown by Russell W. Thaw, c/n 12.
Northrop Gamma 2J: Single-engine (Pratt & Whitney Wasp) three-seat closed-cabin low-wing land monoplane advanced trainer, 1 prototype built, USAAC advanced trainer competition, version of Army A-17 Nomad, c/n 186
Northrop Gamma 2L: Single-engine (delivered without engine) two-seat closed-cabin low-wing land monoplane, 1 built, sold to Bristol Aeroplane Company for Hercules engine testing, c/n 347.
Northrop Gamma 3A: Single-engine (Pratt & Whitney Wasp) single-seat closed-cabin low-wing land monoplane fighter, 1 built, USAAC XP-948, c/n 44.
Northrop Gamma 5A: Single-engine (Pratt & Whitney Wasp) two-seat closed-cabin low-wing land monoplane, 1 built, exported to Japanese Navy 1935, c/n 187.
Northrop Gamma 5B: Single-engine (Pratt & Whitney Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane, 1 built, Spanish Republican Air Force, c/n 188.
Northrop Gamma 5D: Single-engine (Pratt & Whitney S3H-1) two-seat closed-cabin low-wing land monoplane, 1 built, exported to Japanese Navy, c/n 291.

Military Variants

Northrop YA-13: Single-engine (Wright Cyclone) two-seat closed-cabin low-wing land monoplane, 1 built, USAAC light attack aircraft, Gamma 2C (A.C. 34-027, c/n 5).
Northrop XA-16: Single-engine (Pratt & Whitney R-1870-7) two-seat closed-cabin low-wing land monoplane, USAAC light attack aircraft, redesigned & re-engine YA-13 (A.C. 34-027, c/n 5).
Northrop XP-948: Single-engine (Pratt & Whitney R-1870-7) single-seat closed-cabin low-wing land monoplane, 1 built, aka Northrop 3A, USAAC pursuit adaptation of Navy XBT-1 (c/n 44).
Northrop XFT-1: Single-engine (Wright XR-1510-8) single-seat closed-cabin low-wing land monoplane, 1 built, USN experimental fighter (BuNo 9400, c/n 6).
Northrop XFT-2: Single-engine (Wright R-1535-72 single-seat closed-cabin low-wing land monoplane, re-designed and re-engine XFT-1, 1 converted, USN experimental fighter (BuNo 9400, c/n 6).
Northrop A-17: Single-engine (Pratt & Whitney R-1535-11 Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane with fixed landing gear, 109 built, USAAC light attack bomber (A.C. 35-051 to 35-160, c/n 75-184).
Northrop A-17A: Single-engine (Pratt & Whitney Twin Wasp, Jr.) two-seat closed-cabin low-wing land monoplane with retractable gear, 129 built, USAAC light attack aircraft (A.C 36-162 to 36-261, 38-327 to 38-377).
Northrop A-17AS: Single-engine (Pratt & Whitney R-130-41 Wasp) three-seat closed-cabin low-wing land monoplane with retractable gear, 2 built, USAAC staff transport (A.C 36-349 and A.C. 36-360, c/n 289-290).
Northrop XBT-1: Single-engine (Pratt & Whitney R-1535-66) two-seat closed-cabin low-wing land monoplane, 1 built, USN experimental dive-bomber (BuNo 9745, c/n 43).
Northrop BT-1: Single-engine (Pratt & Whitney R-1534-94) two-seat closed-cabin low-wing land monoplane, 54 built, USN dive-bomber (BuNo 0590 to 0626, 0628 to 0643, c/n 293 to 329, 331 to 346).

Northrop Gamma Operators

Military Operators

China
Japan: as BXN
Spain: Spanish Republican Air Force - Northrop 2D and 5B Gamma
United States: United States Army Air Corps

Civil Operators

Manchuria: Manchukuo Manchurian Air Lines
United States: Trans World Airlines

Northrop 5B Specifications and Performance Data

Type

Single-engine two-seat low-wing attack bomber monoplane

Power Plant

(5A): 775-hp Wright Cyclone SR-1820-F52 nine-cylinder air-cooled radial driving a three-blade propeller
(5B): 775-hp Wright Cyclone SR-1820-F52 nine-cylinder air-cooled radial driving a three-blade Hamilton Standard propeller
(5D): 600-hp Pratt & Whitney Wasp R-1340-S3H-1 nine cylinder air-cooled radial driving a two-blade

Dimensions

Wingspan: 47 feet 8¾ inches (14.55 m)
Length: 30 feet 0 inches (9.14 m)
Height: no data
Wing area: no data

Weights and Loadings

Weight loaded: 6,995 lbs (3,173 kg)

Armament

Guns: One 0.50-in fixed machine-gun in each wing outboard of undercarriage, and one 0.30-in flexible ventral gun
Bombs: Six 100 lb (45.4 kg) bombs carried beneath the wing center section.

Performance

Maximum speed at S/L: no data
Maximum speed at 10,000 feet (3,050 m): no data
Cruising speed: no data
Landing speed: no data
Climb to 10,000 feet (3,050 m): no data
Service ceiling: no data
Endurance: no data

References

Wikipedia: Northrop Gamma
Francillon, René J., McDonnell Douglas Aircraft since 1920: Volume I, Putnam Aeronautical Books, London, 1995, ISBN 0-85177-827-5, pp. 215-217
Allen, Richard Sanders, The Northrop Story 1929-1939, Orion Books, New York, 1990, ISBN 0-517-56677-X, pp. 138, 150-155.