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,
Luftwaffe were meeting large numbers of equal if not superior Allied types. Daytime aerial defense against the USAAF's strongly defended heavy bomber forces, particularly the Eighth Air Force and the Fifteenth Air Force, had its successes through the calendar year of 1943. But at the start of 1944, Eighth AF commander Jimmy Doolittle made a major change in offensive fighter tactics, which defeated the "Luftwaffe"s day fighter force from that time onwards. Steadily increasing numbers of the superlative North American P-51 Mustang single-engine fighter, leading the USAAF's bombers into German airspace defeated first the Bf 110 "Zerstörer" wings, then the Fw