Two thousand dollars and a servo flap

Charles Kaman was a Washington engineer who learned helicopters working for Igor Sikorsky. In December 1945 he went out on his own with $2,000 of capital and an invention: the servo flap, a small control surface on each rotor blade that twisted the blade instead of forcing it through heavy linkages. His first helicopter, the K-125, flew on 15 January 1947 with two intermeshing rotors turning in opposite directions, an eggbeater layout that cancelled torque without a tail rotor. Kaman would use it for the rest of the century.

The first turbine helicopter

The improved K-225 of 1949 sold to the US Navy and Coast Guard for $25,000 each. In December 1951 a K-225 fitted with a Boeing turboshaft became the world’s first gas turbine powered helicopter; it is now displayed by the Smithsonian at the Udvar-Hazy Center. In March 1954 a modified HTK-1 became the first twin-turbine helicopter. Anton Flettner, the German pioneer of intermeshing rotors, had emigrated to the United States and became Kaman’s chief designer.

The Huskie’s rescue record

The intermeshing rotors reached their peak in the H-43 Huskie, first flown on 21 April 1953. The US Air Force used it for airfield crash rescue and later for combat rescue in Vietnam. According to Kaman, Huskies flew more rescue missions in the Korean and Vietnam wars than all other aircraft combined. 370 were built, and in October 1961 a Huskie set an altitude record of 10,000 m.

Seasprite at sea

For the navy Kaman went conventional. The Seasprite first flew on 2 July 1959 with a single main rotor, was rebuilt with two engines, and in 1973 became the SH-2F, the US Navy’s first LAMPS anti-submarine helicopter for escort ships. The SH-2G Super Seasprite followed in 1993 and went to Egypt, New Zealand and others; an Australian order ended badly in 2008, when the navy handed all its aircraft back. 184 Seasprites were built. The single-seat K-MAX aerial crane of 1991 revived the intermeshing rotors, and two unmanned K-MAXes hauled cargo for the US Marines in Afghanistan.

Guitars, bearings and a private owner

Kaman also turned aerospace composites into music. A keen guitarist, Charles Kaman founded Ovation Instruments in 1966 and built round-backed composite acoustic guitars. The company later grew into bearings, precision parts and distribution, and made the world’s first production all-composite rotor blade, for the AH-1 Cobra. Charles Kaman died in 2011. K-MAX production closed for a second time in 2023, and in April 2024 the private equity firm Arcline completed a $1.8 billion purchase, taking Kaman private.

工厂

• Bloomfield headquarters · Bloomfield, Connecticut

人们

• Charles Kaman · founder (1919–2011) — Ex-Sikorsky; National Medal of Technology 1996
• Anton Flettner · chief designer — German intermeshing-rotor pioneer; designed the Huskie

纪录和第一

• World’s first gas turbine powered helicopter, modified K-225, December 1951
• World’s first twin-turbine helicopter, modified HTK-1, March 1954
• H-43 Huskie altitude record of 10,000 m, October 1961
• First all-composite main rotor blade, 1960