Messerschmitt Bf 109 was called the Me 109R, suggesting it was just another variant of the standard fighter, but in fact it was a racing aircraft having little in common with the Bf 109. It was powered by the DB 601ARJ, producing 1,156 kW (1,550 hp), but capable of reaching 1,715 kW (2,300 hp). This world record for a piston-engined aircraft was to stand until 1969, when Darryl Greenamyer's modified Grumman F8F Bearcat, "Conquest I", broke it with a 777 km/h (483 mph) record speed. When the Bf 109 was designed in 1934, by a team led by Willy Messerschmitt and Robert Lusser,
Messerschmitt Bf 109 variants as all of the 235 Bf 109Ds still in Luftwaffe service at the beginning of the Poland Campaign were rapidly taken out of service and replaced by the Bf 109E, except in some night fighter units where some examples were used into early 1940. Variants included the D-0 and D-1 models, both having a Junkers Jumo 210D engine and armed with two wing-mounted and two nose-mounted 7.92 mm (.312 in) MG 17s.> The D-2 was an experimental version with an engine-mounted machine gun, but as previously tried, this installation failed. The D-3 was similar to the C-3 but with two