BMW 109-718

The BMW 109-718 was a liquid-fuelled rocket engine that BMW developed at its Bruckmuhl facility in Germany during the Second World War. It was designed as an assist rocket for aircraft, to allow rapid takeoffs or high-speed sprints, and it was combined with a standard BMW 003 jet engine, mounted above the rear turbine casing, to make the 003R variant that gave 1,250 kilograms of thrust at full power. Unlike most rocket-assisted takeoff boosters it stayed with the airframe at all times. The motor had internal and external main chambers cooled by nitric acid oxidiser fed through a coiled spiral tube, and its pumps ran at 17,000 rpm from a power take-off on the jet engine. The unit weighed 80 kilograms, and a Messerschmitt Me 262C-2b with a pair of 718s climbed to 9,150 metres in tests.