01/31/2012. Remarks by Johan Visschedijk: "Bridging the gap between the Northrop Gamma 2E attack bombers exported to China and Britain and the Douglas 8A sold to several overseas air forces, the three Northrop Gamma 5s were designed in parallel with the USAAC A-17 series. Thus, although intended for export markets, these three experimental aircraft closely corresponded to various models in the progressive development of the attack bombers produced for the USAAC.
The first of these aircraft, the Northrop Gamma 5A, bore a marked resemblance to the YA-13 from which it differed in being powered by a 775 hp Wright SR-1820F-52 driving a three-blade propeller and in having a shallower canopy. Assigned the temporary experimental registration X14997 (c/n 187), the Gamma 5A was completed in October 1935. A month later, after completing its manufacturer's trials at Mines Field, the aircraft was shipped to Japan where it was evaluated by the Japanese Navy. It was then dismantled to provide useful engineering data for Japanese aircraft manufacturers.
The Northrop Gamma 5B, which was also completed in October 1935, retained the trousered undercarriage of the Northrop YA-13 and Gamma 5A but was initially powered by a 700 hp Pratt & Whitney Twin Wasp Junior SB-1G fitted in a longer chord cowling and driving a three-blade propeller. Registered NR14998 (c/n 188), this aircraft was flown in late 1935 to Argentina where it was demonstrated to the Fuerza Aerea Argentina. While it was in Buenos Aires, it was re-engined with a 775 hp SR-1820-F52 and its testing eventually led to the Argentine Government placing an order for thirty Model 8A-2s.
In February 1937, the Northrop Gamma 5B was once again re-engined, this time with an 820 hp Wright R-1820G, before being recertificated by the Civil Aeronautics Authority's representative in Buenos Aires. The aircraft was then flown to Mexico City, apparently having been sold to a Henry G. Fletcher. It is believed that the aircraft was registered in Mexico as XA-ABI and that it became the property of a Lieutnant-Colonel Montero.
The Northrop Gamma 5B's fate is unconfirmed but reportedly the Mexican officer was a figurehead of the Republican government of Spain and the aircraft went to Spain in 1937 to be used for training pilots for the Republican AF. Around the end of the year it was assigned to patrol duties along the coast, at least during 1938 it was used in that capacity. Captured as a trophy in the spring of 1939 the Gamma 5B continued service in secondary roles until the early 1950s in the Nationalist AF in Franco's Spain.
The Northrop Gamma 5D, registered X16091 (c/n 291), was completed in August 1936 and corresponded closely to the Northrop A-17AS. Like the A-17AS, the Gamma 5D was fitted with a retractable main undercarriage and was powered by a Pratt & Whitney nine-cylinder radial, in this instance a 600 hp Wasp S3H1 driving a two-blade propeller. The aircraft was exported to Japan where, following testing by the Navy, it provided Nakajima and Mitsubishi with valuable information on the design and operation of retractable undercarriages."