The BMW 003 was an early axial-flow turbojet engine produced by BMW AG in Germany during World War II, it and the Junkers Jumo 004 being the only German turbojet engines to reach production during World War II.
Work had begun on the design of the BMW 003 before its contemporary, the Junkers Jumo 004 engine, but prolonged developmental problems meant that the BMW 003 entered production much later, and the aircraft projects that had been designed with it in mind were re-engined with the Jumo powerplant instead. The most famous case of this was the Messerschmitt Me 262, in two of the V-series prototypes and in the two experimental A-1b aircraft, and the same was true of the Arado Ar 234 and Horten Ho 229. The only production aircraft to use the BMW 003 were the Heinkel He 162 and late, four-engined versions of the Arado Ar 234.
Some 500 BMW 003 engines were built in Germany, but very few were ever installed in aircraft. The engine also formed the basis for turbojet development in Japan during the war, and following the war was produced in the Soviet Union and France.
Construction began late in the same year and the engine ran for the first time in 1940, but produced less than half of the thrust expected, 2.5 kN instead of 6.3 kN. The first flight test took place in mid-1941, mounted underneath a Messerschmitt Bf 110. Problems continued, however, meaning that while the Me 262 (the first aircraft intended to use the engine) was ready for flight-testing, there were no powerplants available for it and it actually began flight tests with a conventional Junkers Jumo 210 piston engine in the nose. It was not until November 1941 that the Me 262 was flown with BMW engines, which both failed during the test, the prototype having to return to the airfield on the power of the piston engine, which luckily, was still fitted.
The general usage of the BMW powerplant was abandoned for the Me 262, except for two experimental examples of the plane known as the Me 262 A-1b. The Me 262 A-1a production version used the competing Junkers Jumo 004 whose heavier weight required the wings to be swept back in order to move the center of gravity into the correct position. Work on the 003 continued anyway, and by late 1942 it had been made far more powerful and reliable. The improved engine was flight tested under a Junkers Ju 88 in October 1943 and was finally ready for mass production in August 1944, in time to power the He 162.
One late version of the engine added a small rocket motor (BMW 109-718) at the rear of the engine, which added some 9.8 kN of thrust for take off and short dashes. In this configuration, it was known as the BMW-003R and was tested, albeit with some serious reliability problems, on a single Me 262 interceptor prototype, the Me 262 C-2b Heimatschützer II, and perhaps a He 162 as well.
The BMW-003 was intended for export to Japan, but working examples of the engine were never supplied. Instead, Japanese engineers used drawings and photos of the engine to design an indigenous turbojet, the Ishikawajima Ne-20.
After the Allied occupation of Germany, Marcel Dassault assisted Hermann Östrich to move from the American Zone of occupied Germany into the French Zone and within a couple of years he was at work for Voisin, a division of SNECMA, France's state-owned aircraft engine company, where he produced the Atar jet engine that powered Dassault's Ouragan and Mystère fighters.