The Messerschmitt-Bölkow-Blohm Bo 105 is a twin-engine light multi-purpose helicopter of German origin. It was developed by Bölkow of Ottobrunn.
The Bo 105 first took flight early in 1967, three years after development on it began. It represents the dawn of aerobatic helicopter flight as the Bo 105 is the first helicopter in history to accomplish maneuvers such as the inverted loop. It’s also noted as the model that pioneered the hinge-less rotor. The Bo 105 was taken into service in 1970.
The Bo 105’s reputation for high levels of maneuverability are well deserved, even by modern standards. In service to this very day, the Bo 105 in aerobatic configuration has wowed audiences at events sponsored by companies such as Red Bull.
During the peak of its service life many pilots had little good to say about the looks of the Bo 105, but when it came to its flight characteristics, cruise speed and useful load capacity the praise was almost universal.
The Bo 105 can perform rapid takeoffs, steep climbs and rolls. The helicopter is cleared for an astounding +3.5G and -1G. It’s also especially resistant to catastrophic dynamic rollover.
Its pioneering hinge-less rotor head consists of a solid titanium block with four rotors bolted directly onto it. It’s the flexibility of the rotor blades themselves that compensate for the immense forces they are subjected to. The composite glass-fiber and plastic material the rotor blades are made from make this possible. The rigid design also enabled designers to remove all active elements besides rotor pitch changes. This simplified design has made for an immensely reliable rotor system. In over six million fleet-wide operating hours there has yet to be a single failure. This (at the time) revolutionary rotor design is likely the main reason for the Bo 105’s exceptional performance and the comparatively long life of the rotor blades.
Over 1500 Bo 105s have been built. In 1975 you would have to fork out just over 350 000 US dollars, but by the 90s the price had climbed to nearly 1.9 million US dollars.
Thanks to its flight characteristics many nations have put the Bo 105 to work as a military and law enforcement aircraft. Fifty-five nations can be counted among the Bo 105’s customers. The EC135 is the Bo 105’s modern successor.