Supercharged racer from a bygone era
This beast of a machine was an unexpected bonus when I called into photograph a private collection in Germany in 2016.
In 1938 NSU began the development of the 350 & 500cc RK bikes. Chief designer was ex-Norton engineer Walter Moore, with Albert Roder (ex-Zundapp) his assistant.
The motor was a DOHC parallel twin with bevel drives to each camshaft. A supercharger was fitted behind the cylinders. Two 350s and a 500 were raced in the 1939 IOM but none finished.
After the war forced induction was still allowed in German domestic competition up until the end of 1950.
NSU returned to racing with revised versions of the RKs in 1949 with Heinz Fleischmann as their main rider and BMW as their principal competitor.
The 500cc bike made 98hp at the start of the season and had a top speed of 270kph.
For record breaking attempts 110hp was available and in 1951 & 1956 an RK powered streamliner achieved 330kph.
Even as late as 1966 Wilhelm Herz raised the 10km average speed record to 309kph.
This is one of the five RK500s constructed.