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 in Yugoslav service Air Training School, both based at Mostar. All of these aircraft were deployed in the fighter/interceptor role. Immediately prior to the German-led Axis invasion of Yugoslavia in April 1941, 64–65 of the original 73 Bf 109E-3s were serviceable. They were allocated as follows: Commencing at 06:45 on 6 April, the "Luftwaffe" launched Operation Retribution, a series of concerted bombing attacks on Belgrade that coincided with air and ground attacks throughout the country. Several waves of German aircraft approached Belgrade during the day, initially Junkers Ju 87 "Stuka" dive-bombers escorted by fighters. All of the Bf 109E-3s of the 51st Fighter