Rigid rotor inherited from the Bo 105, precise maneuvers
The BK117 inherited the fully rigid (hingeless) main rotor system of the MBB Bo 105, the world's first helicopter with a rigid rotor (1967). The feature allows precise maneuvers, responsive control and the ability to operate in marginal weather better than articulated rotors. Combined with a fuselage larger than the Bo 105 (cabin 8-9 PAX vs. 4-5 for the Bo 105), the BK117 entered niches where the Bo 105 was too small: premium EMS, governmental SAR, medium-lift utility.