50 Years After The Bo46 First Flight - Could We Do Better Today?

In January 1964, the maiden flight of an experimental rotorcraft took place in Ottobrunn near Munich, Germany. The aircraft named Bo 46 was a flying testbed for a novel main rotor concept which should allow flight speeds up to the range of 500 kph. The asymmetrical flow conditions at high forward speed should be compensated by a forced lead-lag movement of the main rotor blades, which would decelerate the advancing blade and accelerating the retreating blade. The tests revealed difficulties like unsufficient rool stability in hover or unexpected structural damage of blades and mechanical rotor components. As the funding was not extended to continue this campaign, there was no second chance to prove the concept of the high speed rotor. Based on historical reports and sketches from Hans Derschmidt, a dynamic rotor model was established to investigate whether modern materials and engineering tools would suffice to get this concept realized.