The only major difference was the use of a 12-cylinder inline engine versus the Ar 64's radial.

The Ar 65d was delivered in 1933 and served alongside the Ar 64 in the two fighter groups - Fliegergruppe Döberitz and Fliegergruppe Damm.

However, the next year, 12 of them were presented to Germany's ally - the Royal Bulgarian Air Force.

Bulgarian Air Force Luftwaffe Data from Warplanes of the Third Reich [1]General characteristics Performance Armament

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