Kaman K-225 Explained

The Kaman K-225 is an American experimental helicopter developed by Kaman Aircraft. One example 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.^[1] 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 first gas turbine-powered helicopter in December 1951.^[2] This aircraft is now at the Smithsonian Institution in Washington, D.C.

A standard K-225 is preserved in the New England Air Museum at Windsor Locks Connecticut.

In 1953, the Turkish Army purchased one Kaman K-225 helicopter and a K-225 was the first helicopter flown in Turkey.^[3]

Variants

K-125 :first two-seat prototype with Lycoming O-390-3 engine and moulded plywood fuselage and bubble canopy.

K-190 :improved prototype with Lycoming engine, certified in April 1949

K-190A :open frame three-seat helicopter, powered by a 1750NaN0 Lycoming O-435-C engine. Type certified on April 15, 1949.^[4]

K-190B :four-seat version.

K-225 :improved model, powered by a 2250NaN0 Lycoming O-435-A2 engine, certified on September 16, 1949.^[4]

K-5 :designation for K-225 with Boeing T50-BO-2 model 502 engine.

YH-22 :United States Air Force designation for one K-225 bought for evaluation.

References

Bibliography

• Web site: Hall of Fame/Inventor Profile: Charles Kaman . National Inventors Hall of Fame . 2009-01-27 . dead . https://web.archive.org/web/20090106015708/http://www.invent.org/Hall_Of_Fame/190.html . 2009-01-06 .

Notes and References

1. "Hall of Fame/Inventor Profile: Charles Kaman"
2. http://www.boeing.com/history/boeing/502turbine.html Boeing Model 502 Gas Turbine Engine
3. Web site: Turkish Kaman 225.
4. Web site: Helicopter Specification No. 1H1. September 2, 2022. Federal Aviation Administration. Federal Aviation Administration. faa.gov. September 26, 1950. https://web.archive.org/web/20210419165144/https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3e60365669cd4d2785256715006b5dcc/$FILE/1h1.PDF. April 19, 2021. live.