BMW began building motorcycle engines and then motorcycles after World War I. Its motorcycle brand is now known as BMW Motorrad. Their first successful motorcycle, after the failed Helios and Flink, was the "R32" in 1923. This had a "Boxer" twin engine, in which a cylinder projects into the air-flow from each side of the machine. Apart from their single cylinder models (basically to the same pattern), all their motorcycles used this distinctive layout until the early 1980s. Many BMWs are still produced in this layout, which is designated the R Series.