In 1945, Charles Kaman founded Kaman Aerospace Corporation. Kaman’s first design was certificated in 1949. This helicopter, the two-seat K-190, featured unique solutions to two common helicopter design challenges. To eliminate the torque produced by a single main rotor, the K 190 used two two-bladed, counter-rotating rotors. These rotors are mounted side by side on main shafts that are in close proximity to each other and are designed to intermesh the rotor blades as they rotate. This design eliminates the need for a tail rotor and allows rotor disk dimensions only slightly greater than the diameter of each rotor. A second unique feature addresses a problem all the early helicopter designers struggled with—how to apply the considerable forces involved in providing cyclic and collective control of the main rotor without the use of hydraulic servos. Kaman used a unique but effective approach. Control tabs mounted in the trailing edge of each rotor blade provide control and the cyclic and collective move these control tabs to control the pitch of the main rotor blades. The K-190 was followed by the K-225. After that, Kaman designed and produced a substantial number of designs for the U.S. Armed Forces using both the intermeshing rotor design and conventional main rotor/tail rotor design.
In 1990, Kaman launched its next commercial project, the K-1200 K-Max. The design concept for this helicopter is unique in that it is a single-purpose machine. It is designed for the external lift market and, since it has no seating other than for the pilot, it has no other applications. It also uses the intermeshing rotor design to eliminate the tail rotor and thus improve safety in the external lift environment.
The K-Max is a medium single-engine turbine helicopter. It uses Kaman’s trademark intermeshing two-bladed rotors with control tabs. The two rotors are counter-rotating, so a tail rotor is not required. Applying differential collective to the two rotors provides directional control. A horizontal stabilizer is used to assist with pitch control. One Honeywell T 5317-A1 engine is used, the blades are constructed of composites, and the fuselage is constructed of conventional aluminum alloy. The cabin only seats one, the pilot. A storage compartment is provided below the main transmission. A fixed tricycle landing gear is used.
Design of the K-Max was initiated in 1990 and the first flight of the prototype occurred in 1991. Certification to the standards of FAR 27 was obtained in 1994. IFR certification and approval for external load operations was also obtained. First deliveries occurred in 1994.