Arado Ar.64

Today we start with the rearmament of the Luftwaffe.

The Arado Ar.64 was a German biplane fighter that was designed in the very late 1920s and built for the first time in the very early 1930s.

It was basically a variant of the previously built Arado SD.II and SD.III, it was manufactured by the Arado Handelsgesellschaft in order to comply with an order from the Reichwehrministerium of developing a successor to the Fokker D.XIII, which were the backbone fighter force of the clandestine German air force.

Some variants of this airplane existed:

• Ar.64a: The first prototype, it was flown for the first time in the spring of 1930 and was powered by a Siemens und Halske built 530hp direct-drive Bristol Jupiter VI nine-cylinder radial engine. Just like its predecessors, it was of mixed construction. As we couldn't find a single pic or photo about this one, it's left undrawn
• Ar-64b: Two examples were built of this variant which was powered by a 640hp BMW VI 6,3 12-cylinder Vee-type water-cooled engine. This and the previous one, the 'a' variant were among the last fighters evaluated in Lipetsk. This is undrawn because there aren't graphical references. At least we couldn't find any.
• Ar.64c: This variant, which only one example was built, was powered with the same engine as the prototype, but some minor structural changes were made. Again, we couldn't find graphical evidence, so it's left undrawn.
• Ar.64D: Together with the next variant, the E, it was the first massively produced fighter in Germany since the end of the World War I. This variant introduced redesigned and enlarged vertical tail surfaces plus a revised and improved undercarriage. It was powered by a geared version of the Siemens built 530hp Bristol Jupiter VI nine-cylinder air-cooled radial piston engine which required a four-bladed propeller in order to function properly. 
• Ar.64E: Another production model which was powered by a direct-drive version of the Siemens built Bristol Jupiter VI engine which required only two bladed propellers to work properly. Both this variant and the previous D one, were armed with a pair of 7,92mm MG 17 machine guns. 

A contract for 20 aircraft was placed by the Reichwehrministerium and in the summer of 1932 the deliveries started to roll-out. Those 20 were assigned to the Jagdfliegerschule at Schleißheim and later to the Jagdstaffeln of the Fliegergruppe Döberitz and Fliegergruppe Damm together with some Ar.65s. 

Sources:
1. https://en.wikipedia.org/wiki/Arado_Ar_64
2. Salamander Books - The Complete Book of Fighters