on 20 may 1917, rapp motorenwerke registered the documentation for the construction design for the new engine, dubbed "type iii". friz' design, (based on karl rapp's original design) was laid out as an in-line six-cylinder, which guaranteed optimum balance, with 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. 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. september of the same year, diemer set another world altitude record- this one for a passenger aircraft (8 people on board, 6,750 meters) in a ju f-13 powered by a bmw iiia aircraft engine.