Charles Kaman (1919 - 2011), an aeronautical engineering student, served as an employee to another fabled helicopter developer - Igor Sikorsky of Sikorsky Aircraft - throughout the early 1940s at which time America was embroiled in all-out World War. At age 26, he officially struck out on his own in 1945 to form the Kaman Aircraft Company - this to begin operation out of his mother's home garage.
Kaman began a concerted development effort throughout 1946 to bring about a helicopter design that utilized an "intermeshed" rotor arrangement system with power supplied through a piston engine installation. Necessary stability and control would be provided by way of servo-flaps fitted to the edge of the blades. These blades then, in turn, would spin in a contra-rotating fashion, countering the inherent spin caused by engine torque. As such, there would be no need for a conventional tail rotor - and its complicated and costly shaft assembly running off of the power from the main engine. The prototype design was finalized as the "Kaman K-125A" and first flew on January 15th, 1947.
In 1948, a revised and improved form of the original prototype - the "K-190" - went aloft. The K-190 was then followed in 1950 by the "K-225" prototype which introduced seating for three crew. It was this model that took the interest of the United States Navy which ordered a pair for testing in 1950 as the "XHTK-1". Having been satisfied with the ensuing trials, the US Navy placed a quantitative production order to procure 29 examples of the new helicopter. In the USN inventory, the XHTK-1 prototype designation was graduated to become the "HTK-1" (T for "Training"). Kaman went on to develop the "Kaman Model 600" as a dedicated service version to which the US Navy, USMC and United States Air Force all eventually took ownership of.
The USMC knew the Kaman Model 600 as the HOK-1 (O for "Observation") and this form was powered by a single Pratt & Whitney R-1340-48 Wasp reciprocating, 9-cylinder, air-cooled radial piston engine. The HUK-1 (U for "Utility") became another USN version fitting the Pratt & Whitney R-1340-52 radial piston engine series of which 24 were delivered as such. The USAF designated the new helicopter as the more recognized H-43A "Huskie" (this version based on the USMC HOK-1) and eighteen examples of the type were delivered (after 1962, in which the designation system of American aircraft was restructured, the H-43A became the "HH-43A").
A single K-225 prototype was modified to accept a Boeing YT50 Model 502-2 gasoline turbine engine - in effect becoming the first helicopter in history to successfully mount this engine type, first flight being recorded on December 10th, 1951. The USCG also evaluated the Kaman helicopter design under the designation of "HTK-1G" but did not accept the design. A static test drone for the US military was known as the "HTK-1K".
The Kaman's turbine arrangement was generally sound technology for its time but there was natural thought given to the fitting of a new turboshaft technology engine for added performance. The potential was realized when an Avco Lycoming-brand XT53 engine was installed into a HOK-1. The resulting application proved exceptional and led to the introduction of a new production mark - the "H-43B". First flight of the B-model was recorded on December 13th, 1958. An accident involving the rotors and tail section in 1961 forced the Huskie to undergo several modifications to her empennage, which proved an ongoing process throughout the operational life of the helicopter.
The H-43B was dimensionally larger than the preceding H-43A series and held internal seating for up to eight passengers including applicable gear (rescue and otherwise). The United States military ordered 193 examples of this new version and sent examples to allies overseas. The Kaman B-model version helicopter also went on to set several helicopter-related world records of her time in altitude, range and rate-of-climb. As the H-43 before it, the H-43B later became the "HH-43B" after the 1962 designation restructuring. Similarly, the HUK-1 became the "UH-43C" while the HOK-1 became the "OH-43D". A single OH-43D was converted to an unmanned drone as the "QH-43G". The HTK-1 was now recognized as the "TH-43E".
The final Kaman offering of the Model 600 became the HH-43F which was an HH-43B fitted with a Lycoming T-53-L-11A engine of 825 shaft horsepower and utilizing smaller diameter rotor blades. Forty-two of this model were either produced or converted (the latter from existing HH-43B systems).
Outwardly, the Huskie was of a very utilitarian design with a rounded, yet boxy, fuselage held under an engine fairing that extended rearwards to become the empennage. The cockpit was dominated by a clear forward windscreen that allowed for excellent visibility forward, to the sides and below the aircraft. Entry and exit to and from the aircraft was by way of large sliding doors along the forward fuselage which promoted access to both the cockpit and cabin area. A winch system was set to the right side of the cabin. A windowed cargo door at the extreme rear of the fuselage allowed for complete access to the aircraft rear - and proved optional in some operational circumstances. The powerplant was fitted atop the fuselage roof and each two-bladed main rotor sat atop fixed mast stems, slightly angled outwards from fuselage centerline. The high-mounted nature of the empennage ensured unfettered access to the rear loading area of the aircraft. The tail section itself was rather stubby and straight in its design, ending against a slim horizontal tail plane to which were affixed four vertical tail planes. The undercarriage was fixed in place and consisted of four single-wheeled landing gear legs (with skids) for proper support of the aircraft when at rest on hard or soft terrains.
The Kaman Huskie was a "special" sort of helicopter when in action and seemingly perfect for the military- and civilian-specific roles bestowed upon her by her various operators. She could be made air worthy within one minute of notice and featured a standard operational crew of two. Additionally, she could carry passengers or mission specialists (firefighters; rescue personnel) as needed and their applicable equipment including fire suppression kits hung under the fuselage. Upon arriving on the scene of a downed aircraft, the crew would utilized their suppression kits and rotor wash to handle the flames and move them further away from the pilots. From there, either ground support or the winch system brought the pilot to safety.
According to USAF sources, their first H-43As were delivered in November of 1958 which were then followed by the improved H-43B, procured in some 175 examples. The newer H-43F model was now the "HH-43F" and these variants were noted for their improved engine performance in "Hot-and-High" conditions but were generally similar to the HH-43Bs before them, differing in internal seating space for 11 personnel with equipment. It was these specific production models that went on to serve in the upcoming Vietnam War where she was used to good effect in rescuing downed airman and also being called upon as a firefighting platform for base protection. The HH-43F was powered by a single lower-rated Lycoming T53-L-11A series turboshaft engine developing 860 horsepower which supplied the platform with a top speed of 120 miles per hour, a cruise speed in the vicinity of 105 miles per hour, an operational range of 185 miles and a service veiling of 25,000 feet. In the war, the helicopter received its nickname of "Pedro" and was generally well-liked and respected by her crews, maintenance personnel and those she saved. Only advancing technology would eventually force the awkward-looking Huskie out of frontline use, seeing replacement by more capable helicopter platforms by the end of her suitable tenure. During the war, the Huskie would earn the phrase "Pedro Cared So That Others May Live".
USAF Huskies served with the Air Rescue Center (Aerospace Rescue and Recovery Center after January 8th, 1966) out of Hamilton AFB, Richards-Gebaur AFb and Robins AFB from 1961 to 1970. Additional squadrons included the 42nd, 43rd and 44th Aerospace Rescue and Recovery Squadrons operating from 1970 to 1973. Detachment 5 of the 40th Aerospace Rescue and Recovery Squadron of Udorn RTAFB became the last acting Kaman HH-43 Huskie operator within the USAF on September 30th, 1975.
The USMC received a total of 83 HOKs beginning in April of 1953. The US Navy received a total of 24 HUK-1 platforms, the first coming May 29th, 1958.
Beyond the United States, operators of the Huskie platform included Burma, Colombia, Iran, Morocco, Pakistan and Thailand. Burma received 12 of the type while Colombia and Pakistan each received 6. Morocco and Thailand operated 4 and 3 respectively. The most quantitative operator of the H-43 aside from the United States became then-ally Iran with 17. Several Huskies still exist today, either as static displays or in civilian hands, some of the latter in operational condition.