The idea of installing a Junkers Jumo 213A engine until then mainly used on bombers in a Focke-Wulf 190 airframe was born of a need to improve the high altitude performance of the aircraft the A & F versions in fact suffered a significant drop in speed above 7 000m Armed with two 20mm cannon & two 13mm guns the D-9 was immediately a favourite with pilots who considered it an aircraft equal to the P-51 Mustang In its secondary role as a ground strike aircraft the Dora 9 performed excellently during Operation Bodenplatte the last stand of the 3rd Reich in the Ardennes About 650-700 D versions are thought to have been made of which four still exist today