Shortly before the outbreak of the Second World War, BMW takes over the Brandenburgische Motorenwerke in Berlin-Spandau and factories in Basdorf and Zühlsdorf near Berlin.
Driving a 328 with a streamlined body made from ultra-light aluminum and magnesium alloy, Baron Fritz Huschke von Kanstein wins in 1940, the famous Mille Miglia race with an average speed of 103.4mph.
Following on from the BMW 132 and the Bramo engines, series production of the BMW 801 aircraft engine starts in 1940. By the end of the war, over 20,000 of these 14-cylinder double radial engines will have been built in Munich, Allach, Berlin and Dürrerhof, all of which are fitted with a type of mechanical computer for automatic tuning.
In 1941 all motorcycle production facilities and design documentation are transferred to Eisenach due to the war. The production of the BMW cars is stopped. BMW begins production of the R57 Wehrmacht military motorcycle. It had a 750cc engine with seven forward and two reverse gears. The engine was bolt-on frame allowing easy dismantling and maintenance. The sidecar version drives with differential lock and joint hydraulic brakes for sidecar and rear wheel.
To satisfy wartime demand, the production of rocket engines begins in the Basdorf and Zühlsdorf plants in Berlin in 1942. Although only a small number of these engines are used, rocket construction is one of the reasons why, in 1945, Bayerische Motoren Werke are closed and later dismantled.
BMW works simultaneously on the groundbreaking 109-003 jet engine, one of the first mass-production jet engines in the world, and on the largest ever aircraft piston engine, the BMW 803. A 28-cylinder, four row radial engine, the BMW 803 basic strength of 4,000 hp at 85.5 l displacement; the 003 jet engine has a diesel-powered gas turbine. Its maiden flight is in October 1943 in a Ju 88.
In the early 1940s, BMW develops the 28-cylinder, four-speed 803 engine with two contrarotating propellers and also starts work on jet engines. Tests on the 003 engine begin in October 1943 followed, on 4th February 1944, by the maiden flight of the Arado 234 V long-distance reconnaissance plane with four BMW 003 engines.
Air raids destroy the Munich plant in 1944, but the Allach plant is virtually unharmed at the end of the war. BMW begins plans to rebuild its Munich production plant. Meanwhile they test rockets for the war effort in Basdorf and Zühlsdorf.
At the end of the Second World War, BMW lies in ruins. The works in Eisenach and Dürrerhof, Basdorf and Zühlsdorf are lost. The factory in Munich is dismantled. The victorious Allies impose a three-year ban on production because of the company's involvement in constructing aircraft engines and rockets.
In mid-1945 BMW receives permission to start repairing US army automobiles in Allach. It can also make spare parts for farming machinery and bicycles. Thatâ,"s how the first BMW bicycle with a lightweight aluminum frame comes to life.
Motorcycles can also be made again, but BMW is initially not in a position to do so.
Initially using spare parts, the Eisenach plant continues to build BMW cars for Soviet use, but in 1951 the brand name Eisenacher Motorenwerke (EMW) is introduced. A Soviet joint-stock company called Awtowelo is set up as backer. The factory is nationalised in 1952, and from 1955 it starts production of the 'Wartburg' car brand.
In October 1945 the US military orders the dismantling of the BMW plants in Munich and Allach. This deprives BMW of its control over its possessions in Munich until 1949 - US control lasted until 1955 in Allach. Almost all intact machinery is removed and shipped as reparations all over the world, hitting the Milbertshofen plant in Munich especially hard.
There is almost no activity for BMW in the following years.
At the Geneva Motor Show in 1948, British car companies Arlington-Fraser-Nash and Bristol develop licensed models based on earlier BMWs, since BMW is neither able, nor allowed, to manufacture after the war.
There is though a high demand for the BMW's R24 motorcycle, equipped with a four-gear, single-cylinder with a 247 cc, 12 HP engine. Construction designs for the first post-war BMW motorcycle are ready by summer 1947, and the first R 24 is raffled to the employees shortly before Christmas 1948. The first standard-production model sells spectacularly in a country long-deprived because of war and its after-effects.
BMW is back again: presenting its first motorcycle since 1941 in New York.