On 20 May 1917, Rapp Motorenwerke registered the documentation for the construction design for the new engine, dubbed project "BBE". Friz' design, based on Karl Rapp's design) was laid out as an in-line six-cylinder, which guaranteed optimum balance, therefore few, small vibrations. The engine was successful, but the real breakthrough came in 1917, when Friz integrated a basically simple throttle butterfly into the "high-altitude carburettor", enabling the engine to develop its full power high above the ground. This is precisely the reason why the engine, now dubbed "Type IIIa", had unique superiority in air combat. The water-cooled in-line 6-cylinder engine's reputation grew very quickly. Franz-Zeno Diemer, the pioneering aviator, sets a new world altitude record with a 32,000 ft (9760 m) flight in 1919 using the BMW IVa engine.