Unfortunately for the design team, the Me 209's proposed DB 603A engine was in short supply and they were forced to use the Junkers Motorenwerke firm's Jumo 213A engine. Even though the 35 litre engine displacement Jumo 213 had been deliberately designed to have as many of its engine access points as possible made to be identical with the 44.52 litre displacement DB 603 powerplant (Germany's largest-displacement inverted V12 aircraft engine), this changeover required some reconstruction of the engine cowling and cooling system. The most visible change was the required one to the engine's air intake location, as the Jumo 213's supercharger intake was located on the starboard side of the engine (as standard for all models of the earlier Junkers Jumo 211 inverted V12), versus the DB 603's portside location, the standard for all Daimler-Benz inverted V12 engine designs. The Me 209 featured a new tail section, wings, wide-track landing gear, a taller tail and an annular radiator for the inline engine, which gave the engine a superficial resemblance to a radial engine and to the very similar installation on the Focke-Wulf Fw 190D, which used the same Jumo 213 powerplant.
