Bayerische Flugzeugwerke (BFW) was primarily an aero engine manufacturer prior to 1917; their products designed by Karl Popp and Max Fritz, both aero engineers. In 1917 BFW combined with the neighbouring Gustav Otto company to form BMW GmbH, which became a public company in 1918 with Franz Joseph Popp in charge. With the war lost, BMW’s core business vanished, and it turned its efforts to anything that would earn a Mark, including making office furniture and tool boxes from surplus scrap metal, as well as new agricultural equipment. BMW had no interest whatsoever in motorcycles, and only very reluctantly decided to enter the market with a 150 cc two-stroke named the Flink, followed by the four stroke Helios which had its origins in the British Douglas flat twin design. The Helios had the engine mounted with the crankshaft across the frame, but this soon gave way to a similar but more refined design, the 500 cc M2 B15. In 1923, the first recognisable model with the engine mounted in what was to become BMW’s trademark flat twin, with the cylinders out in the breeze appeared as the side-valve R32, and the company’s fortunes rocketed. The first OHV twin, the R37, appeared in 1925, and both side-valve and OHV designs followed in the next 14 years.