09/30/2010. Designed by Rudolf Kaiser the Ka 6 was first flown in 1955, and by the year 1970, more than 1,200 Ka 6 had been built. The most popular version was the Ka 6CR, of which 700 were built. The pictured Ka 6CR-Pe was a rare version of which only ten were produced. As indicated by Brian Evans, the 'Pe' in the designation stood for 'pendulum elevator', meaning it was fitted with an all flying tail.