Kaman K-225

K-225
XHTK-1 modified with a Boeing 502 (YT50) turboshaft engine
Role	Experimental helicopter
Manufacturer	Kaman Aircraft
First flight	15 January 1947
Status	Retired
Primary user	United States Navy, United States Coast Guard
Number built	7
Unit cost	$25,000

The Kaman K-225 was an experimental helicopter developed by Kaman Aircraft. One was modified to become the world's first gas turbine-powered helicopter.

Design and development

The K-125 was Charles Kaman's first helicopter, which utilized intermeshing rotors and Kaman's patented servo-flap stability control. The K-125 first flew on 15 January 1947.

The K-190 and K-225 were an improved versions of the K-125, which first flew in April and July 1949 respectively. The U.S. Navy bought two and the Coast Guard one for $25,000 each. The United States Air Force evaluated one K-225 with the designation YH-22.

A modified K-225 equipped with a Boeing 502 (YT50) turboshaft engine became the world's first gas turbine- powered helicopter in December 1951. This aircraft is now at the Smithsonian Institution in Washington, D.C.

Variants

K-225

K-125 

first prototype

K-190 

improved prototype version of K-125 and licensed in April 1949

K-225 

improved prototype version of K-125 (and K-190) and licensed in July 1949

YH-22 

United States Aircraft designation for one K-225 bought for evaluation.

XHTK-1

United States Navy designation for two K-225s bought for evaluation.

XHTK-1G

Designation for one K-225 evaluated by the United States Coast Guard

Specifications (K-225)

K-225 displayed at the New England Air Museum, Windsor Locks, Connecticut, in June 2005

Data from

General characteristics

• Crew: two
• Length: 22 ft 5 in (6.83 m)
• Height: 11 ft 0 in (3.35 m)
• Empty weight: 1,799 lb (816 kg)
• Gross weight: 2,703 lb (1,226 kg)
• Powerplant: 1 × Lycoming O-435-2 6-cyl. air-cooled horizontally opposed piston engine, 225 hp (168 kW)
• Main rotor diameter: 2× 38 ft 0 in (11.58 m)

Performance

• Maximum speed: 73 mph (117 km/h; 63 kn)

See also

Related development

• HH-43 Huskie

Aircraft of comparable role, configuration and era

• Flettner Fl 282

References

,Notes

Bibliography

• "Hall of Fame/Inventor Profile: Charles Kaman". National Inventors Hall of Fame. Retrieved 2009-01-27. 

External links

• Eckland, K.O. (2009-03-07). "American Airplane 1949 Popular Science article on Kaman K-190 and the blade intermesh technology developed by Kaman — ie rare photos Ka-Ku". usa: Aerofiles.com. Retrieved 8 May 2012. 
• "New 'Copter Almost Flies Itself"