View source for Kaman K-225

{{Short description|American experimental helicopter}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{|{{Infobox Aircraft Begin
| name = K-225
| image = File:Kaman K-225 - 330-PS-2417 (USN 708453) (18160147725).jpg
| caption = XHTK-1 modified with a [[Boeing T50|Boeing 502 (YT50)]] turboshaft engine
}}{{Infobox Aircraft Type
| type = Experimental [[helicopter]]
| national origin = United States
| manufacturer = [[Kaman Aircraft]]
| designer =
| first flight = 15 January 1947 (K-125)
| introduced =
| retired =
| status = Retired
| primary user = [[United States Navy]]
| more users = [[United States Coast Guard]]
| produced =
| number built = 7
| variants with their own articles =
}}
|}
The '''Kaman K-225''' is an American experimental [[helicopter]] developed by [[Kaman Aircraft]]. One example was modified to become the world's first [[Turboshaft|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.<ref name="NIHF">"Hall of Fame/Inventor Profile: Charles Kaman"</ref> 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 $25,000 each. The United States Air Force evaluated one K-225 with the designation YH-22.
A modified K-225 equipped with a [[Boeing T50|Boeing 502 (YT50)]] turboshaft engine became the first gas turbine-powered helicopter in December 1951.<ref>[http://www.boeing.com/history/boeing/502turbine.html Boeing Model 502 Gas Turbine Engine] {{webarchive|url=https://web.archive.org/web/20110622052807/http://www.boeing.com/history/boeing/502turbine.html |date=2011-06-22 }}</ref> This aircraft is now at the [[Smithsonian Institution]] in Washington, D.C.
A standard K-225 is preserved in the [[New England Air Museum]] at [[Windsor Locks]] [[Connecticut]].
In 1953, the Turkish Army purchased one Kaman K-225 helicopter and a K-225 was the first helicopter flown in Turkey.<ref>{{Cite web|title=Turkish Kaman 225|url=https://twitter.com/Alfred_Bubi/status/1187078039714353152}}</ref>
==Variants==
[[File:Kaman K-225.JPG|thumb|K-225]]
[[File:Kaman K-225 N401A New England Air Msm 09.06.05R.jpg|thumb|The fifth K-225 to be built displayed at the [[New England Air Museum]], Windsor Locks, [[Connecticut]], in June 2005]]
;K-125  :first two-seat prototype with {{cvt|125|hp}} [[Lycoming O-390]]-3 engine and moulded plywood fuselage and bubble canopy.
;K-190  :improved prototype with {{cvt|190|hp}} Lycoming engine, marketed as an open cockpit crop-duster, certified in April 1949<ref>{{Cite web |title=Kaman K-225 |url=https://airandspace.si.edu/collection-objects/kaman-k-225/nasm_A19571016000 |access-date=21 November 2024 |website=National Air and Space Museum |language=en-US}}</ref>
;K-190A :open frame three-seat helicopter, powered by a {{convert|175|hp|kW|0|abbr=on}} [[Lycoming O-435]]-C engine. Type certified on April 15, 1949.<ref name="1H1">{{cite web|url= https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3e60365669cd4d2785256715006b5dcc/$FILE/1h1.PDF|title= Helicopter Specification No. 1H1|access-date= September 2, 2022|author= Federal Aviation Administration|author-link= Federal Aviation Administration|work= faa.gov|date= September 26, 1950|archive-url= https://web.archive.org/web/20210419165144/https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3e60365669cd4d2785256715006b5dcc/$FILE/1h1.PDF|archive-date= April 19, 2021|url-status= live}}</ref>
;K-190B :four-seat version.
;K-225  :improved model, powered by a {{convert|225|hp|kW|0|abbr=on}} [[Lycoming O-435]]-A2 engine, certified on September 16, 1949.<ref name="1H1"/>
;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.
==Specifications (K-225)==
[[File:Kaman K-225 3-view line drawing.png|thumb|3-view line drawing of the Kaman K-225]]
{{Aircraft specs
|ref=<ref name="eckland">{{cite web|url=http://aerofiles.com/_k.html|title=American Airplane Ka-Ku|last=Eckland|first=K.O.|date=2009-03-07|publisher=Aerofiles.com|access-date=8 May 2012|location=usa}}</ref><ref name="museum">[http://airandspace.si.edu/collections/artifact.cfm?id=A19571016000 Kaman K-225] {{Webarchive|url=https://web.archive.org/web/20160304022530/http://airandspace.si.edu/collections/artifact.cfm?id=A19571016000 |date=2016-03-04 }}, Smithsonian [[National Air and Space Museum]], cit. 28. 1. 2013</ref>
|prime units?=imp
<!--General characteristics-->
|crew= two
|length m= 6.83
|height m= 3.35
|empty weight kg= 816
|gross weight kg= 1226
<!--Powerplant-->
|eng1 number=1
|eng1 name=[[Lycoming O-435-2]]
|eng1 type=6-cyl. air-cooled horizontally opposed piston engine
|eng1 hp=225
|rot number= 2
|rot dia m= 11.58
<!--Performance-->
|max speed mph=73
|endurance=<!-- if range unknown -->
|ceiling m=
|ceiling ft=
|climb rate ms=
|climb rate ftmin=
|climb rate note=
}}
==See also==
{{aircontent
|related=
* [[Kaman HH-43 Huskie]]
|similar aircraft=
* [[Flettner Fl 282]]
|lists=
|see also=
}}
==References==
{{Commons category}}
===Notes===
{{reflist}}
===Bibliography===
* {{cite web |title=Hall of Fame/Inventor Profile: Charles Kaman |work=National Inventors Hall of Fame |url=http://www.invent.org/hall_of_fame/190.html |access-date=2009-01-27 |url-status=dead |archive-url=https://web.archive.org/web/20090106015708/http://www.invent.org/Hall_Of_Fame/190.html |archive-date=2009-01-06 }}
{{Kaman aircraft}}
{{USAF helicopters}}
{{US Navy experimental aircraft}}
[[Category:1940s United States helicopters]]
[[Category:Kaman aircraft|K-225]]
[[Category:1940s United States experimental aircraft]]
[[Category:Synchropters]]
[[Category:Single-engined piston helicopters]]
[[Category:Aircraft first flown in 1947]]
[[Category:Aircraft with fixed tricycle landing gear]]