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Kaman HTK-1

In 1950 at the same time as Kaman was working on the Marine Corps Observation Helicopter, the Company was awarded another contract by the Navy to produce a trainer helicopter. Designated the HTK-1, this was a refined version of the earlier K-225 and twenty-nine of these HTK-1s were built between 1951 and 1953. They served with the Navy at Pensacola until 1957. The HTK-1 was powered by a Lycoming O-435-4 piston engine developing 240hp.

P.Allen "The Helicopter", 1996

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Photo Gallery 

The first production HTK-1 for the Navy is flanked by a similar commercial machine. A large ventral/dorsal fin was later added to the center tail section.

Painted overall Orange-Yellow, this HTK-1 wears the markings of Helicopter Training Unit One (HTU-1). Kaman's trademark servo flaps are clearly visible on the rotors. A locally-fabricated skid has been added to the center tail fin.

An HTK U.S. Navy trainer seen in April 1951.

Personnel of HU-1 "Flying Angels" test a 6m nylon rescue ladder they devised for their HTK-1 during July 1958. The HTK-1 shared rescue duties at NAS Barbers Point with a hoist-equipped Sikorsky HO3S-1

The second production HTK-1 practices water landings during float gear evaluations.

The first Kaman drone helicopter, the HTK-1K nicknamed the "Yellow Peril", in its original configuration, is tethered for preliminary flight trials during Spring 1953.

The "Yellow Peril", after modifications, is put through its paces during the late 1950s.

During 1958, one of Kaman's drones was tested with an elctric motor in place of its piston engine. Current from a generator on the ground powered the motor.

An HTK U.S. Navy trainer seen in April 1951.

The HTK-1 Bureau Number 128657 was extensively modified to become the world's first twin-turbine helicopter. Here, the aircraft makes a sharp flare on landing during 1956.

The first twin turbine helicopter. In March 1954 the experimental HTK-2 was fitted with twin Boeing 502-2 engines.

Technical data for Kaman HTK-1

Engine: 1 x Lycoming O-435 pistone engine, rated at 180kW, rotor diameter: 12.2m, take-off weight: 1155kg, empty weight: 735kg, max speed: 130km/h, max speed: 130km/h, cruising speed: 101km/h, range: 212km

ZiHQSzjHvCuHFYMoN, e-mail, 14.03.2023reply


XTVNbrUGkkgLBpnUCRNb, e-mail, 16.08.2022reply


S. Cummings, e-mail, 09.03.2020reply

My mother, Doris Prario, was the first woman to fly the K-240, soloing Fri, 13 June 1958 after 10 hours of instruction in San Diego, CA. The event was later documented by the San Diego Union-Tribune, 5 Oct 1958 edition.

John Newell, e-mail, 28.07.2020 S. Cummings

My sister and I got a ride in a Kaman K-240 at the Lazy 8 Ranch resort in Pauma Valley CA in about 1959 /1960. I think we were 7 and 9 years old. I am wondering if this was the same helicopter your mother soloed in SD in 1958? Our pilot was a middle aged man.


Scott Cummings, e-mail, 07.09.2020 John Newell

Could be, but I don't know who her instructor was. My mom was pregnant with me at the time of her training, and her doctor recommended she not pursue her helicopter rating because of the vibration from the Kaman (she was already a fixed-wing private pilot).


Earl L. Roemer, e-mail, 11.02.2018reply

I owned, flew (most briefly!) and personally restored the Kaman HTK-1 on display at Tillamook. It has a Lycoming O-540, 240 hp engine on it...from the factory. I owned the last 3 of the 29 manufactured. I have extensive photos--the museum wanted none of them.

Cordell Bahn, e-mail, 19.09.2015reply

Yesterday I was looking at a Kaman HTK-1 at the Tillamook Aviation Museum in Oregon and noted that it had a six cylinder engine, not a four. Six is the number noted in other sources of information on the O-435. I'd appreciate anything that anyone might ad. Thank you.

Roger Desjardins, e-mail, 02.12.2010reply

Very nice webpage. I wonder if Microsoft finally incorporated an early years Kaman into their Flightsimulator versions after 2004. Thats the version I fly at present. I spend all my spare time flying the Robinson R22 Beta II in simulation but I sure would like to fly a Kaman to get a feel for the handling of a twin rotor helicopter.

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