Developed from SD.II and SD.III prototypes that Walter Rethel produced at the request of Reichswehrministerium, the Ar 64 was a single-seat biplane fighter intended to succeed Fokker D.XIII. It was a traditional biplane with unequal wings of mixed construction, the aerofoil having a timber structure and the fuselage a metal tubular structure, both fabric covered. The landing gear was fixed, with a split axle.
Arado Ar 64a: First prototype, powered by a Bristol-built Jupiter VI, 530 hp licensed built by Siemens Halske and with a four-bladed wooden propeller.
Arado Ar 64b: The second and third prototypes, tested with Lipetsk in 1931, were powered by a 12 cylinders BMW VI 6,3 of 640 hp and were used for the development of the Ar 65.
Arado Ar 64c: The last prototype appeared in 1931, and was distinguished from the first by a reinforced structure and a four-bladed propeller of large diameter.
Arado Ar 64D: A production version powered by a Jupiter VI, identifiable with a modified landing gear and a two-bladed propeller. The armament was proposed to be 2 7,9 mm machine-guns but it is very probable that they were not fitted on the 19 aircraft of the DVS during 1934/1935. These aircraft were used as advanced trainer by civil and military pilots.
Arado Ar 64E: The last version, powered by a Jupiter VI. Used by Jagdstaffeln of Fliegergruppe Döberitz and Damm, along with Ar 65.
30 Ar 64 were ordered by Luftwaffe clandestine between 1931 and 1934, including 12 to produce by Focke-Wulf. 6 Ar 64D and 5 Ar 64E were in account at April 1, 1933. The last specimens were delivered during 1934 and, in spite of the arrival of Ar 65, intended to succeed to him, 21 Ar 64 remained in service on July 1, 1936.
The first Ar 64 had been used briefly for tests powered by a Rolls-Royce engine before ordering 24 to be delivered at the beginning of 1933, but by April 1936 they had received only 19 planes.