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Incidentally, this aircraft was the first in the Arado poduction series to divert from the normal numbering sequence, by using the '2' prefix for a single engine fighter. Arado numbering would normally be, for example Ar196, where the '1' denotes a single engine type, with twin engined aircraft bearing the '2' prefix, for example Ar234. It is thought that the '290' number was allocated because other twin, or multi-engined designs were already in production or development, and the '290' was far enough out of sequence to avoid confusion. Also, research to date indicated that there was a requirement to align the type with the FW190 whilst at the same time providing a cover against allied intelligence, whereby it was hoped that the Ar290 would be thought to be a further development of the Focke Wulf fighter, helped, no doubt, by the similarities in shape.
Unfortunately, as is often the case in areas of research where little information exists, it is very possible that this could be an instance of bovinus effluentis......