Walter Kaaden

Walter Kaaden (1 September 1919 – 3 March 1996) was a German engineer who improved the performance of two-stroke engines by understanding the role of resonance waves in the exhaust system. Working for the VEB Motorradwerk Zschopau part of the Industrieverband Fahrzeugbau (IFA), he introduced milestone improvements in two-stroke engines. His understanding of gas flow and resonance enabled him to make the first engine to achieve 200BHP/litre with his 1961 125cc racer. His motorcycle engines were ridden to 13 Grand Prix victories and a further 105 podium finishes between 1955 and 1976.

Walter Kaaden was born in Pobershau, Saxony, Germany. His father worked as chauffeur to the sales manager at the DKW factory (from 1932 onwards, part of Auto Union AG). At eight years old he attended the opening of the Nürburgring racing circuit, a formative event to which he later attributed his enthusiasm for engineering. By February 1953, Zimmermann was finally persuaded and by March 1953, Kurt Kämpf had been moved sideways within IFA to make way for his successor, Walter Kaaden. The results of Kaaden's arrival as IFA's racing manager and a ZPH engine to copy, was the 1953 IFA factory racer featuring a rotary disc valve and many other ZPH features. This two stroke 125cc racing engine was producing 13 bhp, more than 100 bhp/litre. This engine was further developed to produce 25 bhp at 10,800rev/min.

In 1955, Kaaden turned his attention to the expansion chambers invented by Erich Wolf (the DKW designer) that had first appeared on DKW's 1951 racers. Kurt Kämpf had copied and fitted replicas of Wolf's design to the 1952 IFA racers. Working with extremely limited resources, in 1955, Kaaden developed the expansion chamber idea using an oscilloscope to examine the resonance in the exhaust system. From this he devised profiles to maximise the engine's efficiency.