Rapp Motorenwerke GmbH was a German aircraft engine manufacturer based in Munich, Bavaria.

The company was established in Milbertshofen on the former site of the Munich branch of Flugwerk Deutschland GmbH, a firm at which Karl Rapp had held a leading position and that had gone into liquidation in the summer of 1913.

because the vertical timing shaft that drove the overhead camshaft came up between the two rearmost cylinder pairs instead of at the rear end.

When the engine failed at the acceptance test in January 1916, no further orders were placed by the German authorities, and the Austro-Hungarian Navy remained the only customer.

Meanwhile, Franz Josef Popp had noted the facilities of Rapp Motorenwerke were ideal for engine production, having the necessary workforce and equipment.

With Friz' arrival in 1916, the original Rapp designs were also worked on to create a "high altitude" aero engine that would give the Imperial Army strategic air superiority in combat.

Franz-Zeno Diemer, the pioneering aviator and test pilot for the company, sets a new world altitude record with a 32,000 ft (9,760 m) flight in 1919 flying a DFW F 37/III (experimental two-seater, often referred to as the C-IV) with a BMW Type IV aircraft engine.

The decision by the Prussian Army Administration to order 600 units of the innovative high-altitude aero engine (project name "BBE") prompted reorganizing the legal structure of the company.

The aero engine developed by Friz had turned Rapp Motorenwerke into an essential contributor to the war effort virtually overnight.

From the middle of 1917 onward, the business, which would probably have disappeared from history never to be heard of again, now enjoyed the undivided attention of the armed services and other governmental bodies.

While the development side was placed under Max Friz as chief designer, Franz Josef Popp took over the post of managing director.

In 1922, the company changed its name to Süddeutsche Bremsen-AG [de] after the BMW name and engine-making assets were transferred to Bayerische Flugzeugwerke, which had been known as Otto Flugmaschinenfabrik earlier in its history.