View source for Kawasaki OH-1

{{Short description|Japanese scout/observation helicopter}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout, and guidelines. -->
{{Infobox aircraft
  |name = OH-1
  |image = File:ＯＨ－１ (4).jpg
  |caption = A Kawasaki OH-1 in flight
  |type = [[Observation helicopter|Scout/observation helicopter]]
  |national_origin = Japan
  |manufacturer = [[Kawasaki Aerospace Company]]
  |designer =
  |first_flight = 6 August 1996
  |introduction = 2000
  |retired =
  |status = In service
  |primary_user = [[Japan Ground Self-Defense Force]]
  |more_users =
  |produced = 1996–2013
  |number_built = 38 as of 2013<ref name = "fore inter">{{cite web | url=https://www.forecastinternational.com/archive/disp_pdf.cfm?DACH_RECNO=1007 | archive-url=https://web.archive.org/web/20160807192301/https://www.forecastinternational.com/archive/disp_pdf.cfm?DACH_RECNO=1007 | archive-date=2016-08-07 | title=Forecast International: Intelligence Center }}</ref>
  |unit cost = $24.3 million (2013, estimate)<ref name = "fore inter"/>
  |developed_from =
  |variants =
}}
The '''Kawasaki OH-1''' (nickname: "Ninja") is a military [[Observation helicopter|scout/observation]] [[helicopter]] developed and manufactured by the [[Kawasaki Aerospace Company]]. The primary operator is the [[Japan Ground Self-Defense Force]] (JGSDF), who originally procured the OH-1 as a domestically produced successor to their existing [[Hughes H-6|OH-6D ''Loach'']] fleet. The OH-1 has the distinction of being the first helicopter to be entirely produced in Japan.<ref name = "kawa prof"/>

In addition to its use as an observation helicopter, it can also be armed to directly participate in combat; such weapons include a limited quantity of [[air-to-air missiles]] for self-defense purposes. Several variants of the OH-1 have been proposed, these have included derivatives of the type to serve as an [[attack helicopter]] as well as an aborted project to develop a [[utility helicopter]]. As of March 2014, a total of 38 OH-1s have entered service with the JGSDF; so far these complement the existing OH-6Ds rather than replace them.<ref>{{cite web |url=http://www.clearing.mod.go.jp/hakusho_data/2009/2009/html/ls229000.html |title=第II部 わが国の防衛政策の基本と防衛力整備 |language=ja |access-date=15 June 2013 |publisher=Japanese Ministry of Defense}}</ref>

In December 2022, the Japanese government decided to replace 33 OH -1, 12 [[AH-64D]], 47 [[AH-1S]], and 26 [[U-125A]] with unmanned aerial vehicles. Japan plans to increase its defense budget from 1.24% of GDP in fiscal 2021 to around 2.0% within 10 years, and has decided to retire these helicopters and aircraft as part of an effort to spend its defense budget efficiently.<ref>[https://web.archive.org/web/20221209222859/https://www.yomiuri.co.jp/politics/20221209-OYT1T50038/ 空自捜索機や陸自戦闘ヘリを廃止、無人機で代替へ…防衛予算効率化] [[Yomiuri Shimbun]]. 9 December 2022.</ref>

==Development==

===Origins===
During the late 1980s, the JGSDF developed a requirement for a new scout/observation helicopter to replace its Kawasaki license-built OH-6Ds, which became the OH-X programme.<ref name="WAPJ">Aoki 1999, pp. 37–44.</ref> In June 1989, the JGSDF announced their intention to pursue the development of the OH-X.<ref name = "fore inter"/> Several proposals to meet the OH-X requirement were submitted by Kawasaki, [[Fuji Heavy Industries|Fuji]] and [[Mitsubishi Heavy Industries|Mitsubishi]]. In 1991, Kawasaki's proposal was selected by the JGSDF's Technical Research and Development Institute as the prime contractor for the OH-X programme.<ref name = "fore inter"/> On 18 September 1992, the Kawasaki design formally appointed by the Ministry of Defense as the winner.<ref name = "kawa prof">[http://global.kawasaki.com/en/mobility/air/helicopters/oh_1.html "OH-1 Light Observation Helicopter."] ''Kawasaki'', Retrieved: 26 June 2016.</ref><ref name="WAPJ"/> Kawasaki was made responsible for producing 50 percent of the airframe, as well as coordinating development of the rotor system; the remaining airframe elements were manufactured by Mitsubishi and Fuji.<ref name = "fore inter"/> Development was formally launched in October 1992.<ref name = "fore inter"/>

[[File:JGSDF OH-1 20120108-02.JPG|thumb|A JGSDF OH-1, 2012]]

In early 1996, the first OH-1 prototype was rolled out.<ref name = "fore inter"/> On 6 August 1996, the first of four OH-1 prototypes (designated XOH-1) performed the type's [[maiden flight]]. All four prototypes were flying by March 1997.<ref name = "fore inter"/> The four prototypes were delivered to the Japanese Defence Agency for service testing from June to August 1997.<ref name="Brasseys 99 p305">Taylor 1999, p. 305.</ref> By April 1998, flight testing of the prototypes was reportedly around half way complete, having accumulated a combined 400 flight hours during testing, further tests focused on flight validation, operational evaluation, and mission equipment functionality.<ref name = "production"/> These four prototype aircraft were all later remanufactured to conform to production standards and redelivered under new serial numbers to the JGSDF.<ref name = "fore inter"/>

In June 1998, in response to the finalising of a production contract and an initial order for two OH-1s having been placed earlier that year, the manufacture of production OH-1s formally commenced;<ref name="Brasseys 99 p305"/><ref name = "production">Lewis, Paul. [https://www.flightglobal.com/news/articles/first-oh-1-scout-helicopters-poised-for-series-produ-36483/ "First OH-1 scout helicopters poised for series production."] ''Flight International'', 29 April 1998.</ref> By the late 1990s, the JGSDF had announced that it had planned to procure between 150<ref name="WAPJ"/> and 250 OH-Xs to meet its requirements.<ref name = "fore inter"/><ref name="Brasseys 99 p305"/> This figure was significantly fewer than the 297 OH-6Ds that were in active service by March 1995, and there were repeated concerns that numbers could be further curtailed as a result of the impact of defense budget cuts. Procurement, and thus production, of the OH-1 was of a slow pace; each year, only a handful of rotorcraft would normally be purchased, such as a pair of OH-1s being the only units procured in 2004.<ref>Sobie, Brendan. "[http://www.flightglobal.com/pdfarchive/view/2004/2004-01%20-%200020.html Defence cuts force Japan to slow helicopter output]". ''[[Flight International]]'', 13–19 January 2004. p. 18.</ref><ref>[https://www.flightglobal.com/news/articles/reality-check-188064/ "Reality check."] ''Flight International'', 28 September 2004.</ref> By 2013, production of the OH-1 was reportedly as presumed to have been terminated.<ref name = "fore inter"/>

===Further development===
During the 1990s, the JGSDF was interested in procuring a new attack helicopter during the following decade, seeking to replace the Fuji-built [[Bell AH-1 Cobra]] fleet. Amongst the proposals produced by Japanese industries was a derivative of the OH-1, tentatively designated as the ''AH-2''.<ref>Lewis, Paul. [https://www.flightglobal.com/news/articles/japan-eyes-attack-helicopter-12290/ "Japan eyes attack helicopter."] ''Flight International'', 31 July 1996.</ref><ref>[https://www.flightglobal.com/news/articles/japan-ready-to-flight-test-attack-helicopter-43620/ "Japan ready to flight test attack helicopter."] ''Flight International'', 7 October 1998.</ref> In 1999, it was revealed that the JGSDF was actively studying the modification of the OH-1 into an attack helicopter suitable to their requirements.<ref>Jeziorski, Andrzej. [https://www.flightglobal.com/news/articles/japans-anti-tank-oh-1-study-heralds-further-delay-t-54717/ "Japan's anti-tank OH-1 study heralds further delay to AH-X."] ''Flight International'', 4 August 1999.</ref><ref>[https://www.flightglobal.com/news/articles/ah-x-bidders-await-end-of-year-request-63728/ "AH-X bidders await end-of-year request."] ''Flight International'', 28 March 2000.</ref> The OH-1 had been intentionally designed with additional margin to accommodate such growth of scope, the main limiting factors being its transmission and engines. The AH-2 proposal would have involved installing uprated engines and the addition of new unspecified armaments for [[anti-tank]] combat missions; [[Boeing]] in particular was dismissive of the value of the proposed rotorcraft, claiming that it "cannot fulfill the attack requirement".<ref>[https://www.flightglobal.com/news/articles/japan-rethinks-helicopter-needs-178913/ "Japan rethinks helicopter needs."] ''Flight International'', 16 March 2004.</ref> Kawasaki's proposal was ultimately rejected in favour of a locally-built variant of the [[Boeing AH-64 Apache]].<ref name = "fore inter"/>

[[File:ＯＨ－１24.01.10 東方航・初飛行 R 装備 56.jpg|thumb|left|A pair of OH-1s in formation flight]]

In 2005, Kawasaki proposed the development of a utility-orientated derivative of the OH-1 in response to the fledgling UH-X programme, which intended to replace the JGSDF's outdated fleet of Fuji-built [[Bell UH-1 Iroquois|Bell UH-1J Iroquois]] helicopters.<ref>[https://www.flightglobal.com/news/articles/khi-prepares-bid-for-uh-x-198979/ "KHI prepares bid for UH-X."] ''Flight International'', 14 June 2005.</ref> This variant, which would have used the OH-1 as a base, would have featured a new cabin, avionics, transmission and engines, but would have also retained a high level of commonality between the observation and utility models. In 2006, the Japanese government approved a request to fund development of a more powerful variant of the OH-1's Mitsubishi TS1-10 engine.<ref>[https://www.flightglobal.com/news/articles/kawasaki-to-develop-new-version-of-oh-1-helicopter-205910/ "Kawasaki to develop new version of OH-1 helicopter."] ''Flight International'', 11 April 2006.</ref> In March 2007, Kawasaki was reportedly close to finalizing its plans for the utility-orientated OH-1 derivative of the OH-1.<ref name = "util 2007">[https://www.flightglobal.com/news/articles/kawasaki-to-upgrade-oh-1-for-utility-role-212532/ "Kawasaki to upgrade OH-1 for utility role."] ''Flight International'', 13 March 2007.</ref> In 2012, a refreshed proposal for the UH-X requirement was made by Kawasaki, emphasizing its use of OH-1 technology.<ref>Osborne, Tony. [https://www.shephardmedia.com/news/rotorhub/kawasaki-leverage-oh-1-technology-new-utility-heli/ "Kawasaki to leverage OH-1 technology in new utility helicopter."] ''Shepard Media'', 29 May 2012.</ref> In July 2015, the Japanese Ministry of Defense (MoD) announced its decision to accept a rival bid made by Fuji/Bell to domestically produce a modified version of the [[Bell 412]] to meet the UH-X requirement instead.<ref>Grevatt, Jon. [http://www.janes.com/article/53076/japan-selects-fuji-bell-option-for-uh-x-programme "Japan selects Fuji/Bell option for UH-X programme."] ''IHS Jane's Defence Industry'', 19 July 2015.</ref>

In early 2007, Kawasaki confirmed that it was studying several capability improvements for the OH-1 in terms of adaptability, maneuverability and stability; industry sources also claimed that improvements to the range of the OH-1 along with significant power output increases from the type's TS-1-10 engines.<ref name = "util 2007"/> Alternative powerplants for the OH-1 have also been suggested, such as the [[LHTEC T800]] and the [[MTR MTR390]].<ref name = "production"/> In late 2008, Kawasaki was considered implementing a series of improvements aimed at increasing the payload of OH-1; this proposed modification was dependent upon demand from the Japanese defense ministry.<ref>Govindasamy, Siva. [https://www.flightglobal.com/news/articles/kawasaki-talks-civil-316324/ "Kawasaki talks civil."] ''Flight International'', 23 September 2008.</ref>

==Design==
[[File:JGSDF OH-1（32622） electro-optical sensor turret.JPG|thumb|The electro-optical sensor on upper fuselage of an OH-1]]

The OH-1 Light Observation Helicopter is a [[tandem]]-seat, twin-engine scout helicopter. It has a narrow fuselage fitted with small stub wings and a non-retractable [[conventional landing gear|tail wheel undercarriage]]. The OH-1 is suited to armed scout, light escort, and observation duties.<ref name = "fore inter"/> It is equipped with an [[automatic pilot]] system with flight holding functionality, while the cockpit features a multi-display system to lower workloads on its two-man crew.<ref name = "kawa prof"/>

The OH-1 is powered by a pair of [[Mitsubishi TS1]] [[turboshaft]] engines, equipped with [[FADEC|Full Authority Digital Engine Controls]] (FADEC), which drives a four-blade [[Composite material|composite]] main rotor with a bearingless rotor hub along with a [[Fenestron]]-type anti-torque [[tail rotor]] (an enclosed tail-fan unit). The Fenestron uses eight asymmetrically spaced blades to reduce both noise and vibration.<ref name = "fore inter"/><ref name="WAPJ"/>

A roof-mounted [[electro-optical sensor]] turret is located forward of the rotor head, containing a [[forward looking infrared]] sensor, a [[laser rangefinder]] and a colour TV camera.  A total of four [[hardpoint]]s are fitted under the rotorcraft's stub wings to allow the carriage of external stores, these have a total capacity of 132&nbsp;kg (291&nbsp;lb). The outer pylons can carry four [[Type 91 surface-to-air missile|Type 91 guided surface-to-air missiles]], while the inner pylons are capable of carrying external fuel tanks for additional range or endurance.<ref name="WAPJ"/> No additional armament is typically fitted.<ref name="WAPJ"/>

==Operational history==
In January 2000, the first production standard OH-1 was delivered to the JGSDF.<ref name = "fore inter"/> The OH-1 is slated to replace the Hughes OH-6D, which remains in service as the primary aircraft in this role.

==Variants==
* '''XOH-1''': Prototype version
* '''OH-1''': Production model, used as an observation helicopter
* '''AH-2''': Proposed attack helicopter derivative that would have featured uprated engines and additional anti-tank armaments; rejected in favour of [[Boeing AH-64 Apache]].<ref name = "fore inter"/>

==Operators==
; {{JPN}}
* [[Japan Ground Self-Defense Force]]<ref name="World Air Forces 2014">{{cite web |title = World Air Forces 2014 |publisher= Flightglobal Insight |year= 2014 }}</ref>

==Specifications (OH-1)==
[[File:JGSDF OH-1(32634) cockpit right rear view at Maizuru Air Station July 27, 2014.jpg|thumb|Cockpit of an OH-1]]
[[File:JGSDF OH-1(32634) Fenestron-type rotor-in-tail fan 20140727.JPG|thumb|[[Fenestron]] tail rotor, note the asymmetrical blades]]
{{Aircraft specs
|ref=Kawasaki Aerospace<ref name = "kawa prof"/><!-- reference -->
|prime units?=met
<!--
        General characteristics
-->
|crew=2 (pilot and observer)
|length m=12
|height m=3.8
|empty weight kg=2,450
|max takeoff weight kg=4,000

<!--
        Powerplant
-->
|eng1 number=2
|eng1 name={{Interlanguage link multi|Mitsubishi TS1-M-10|2= ja|3=TS1 (エンジン)|preserve=1}}
|eng1 type=turboshaft engines
|eng1 kw=660

|rot number=1
|rot dia m=11.6
|rot area sqm=105.7
<!--
        Performance
-->
|perfhide=

|max speed kmh=278
|cruise speed kmh=220
|range km=550
|ferry range km=720
|ceiling m=4,880
<!--
        Armament
-->
|hardpoints= 4 × hardpoints under stub wings for auxiliary fuel tanks (inner hardpoints) and [[Type 91 surface-to-air missile|Type 91]] air-to-air missiles (outer hardpoints)<ref>Jackson 2007, pp. 395–396</ref>
}}

==See also==
{{External media|topic= |width=20% |float=right |video1=[https://www.youtube.com/watch?v=RYeY2bZqdsw Kawasaki OH-1 Public Flight Demonstration] |video2=[https://www.youtube.com/watch?v=5rWMXZgSkTc OH-1 Performing Maneuvers and Landing] |video3=}}
{{aircontent
|related=
|similar aircraft=
* [[Bell ARH-70 Arapaho]]
* [[Bell 360 Invictus]]
* [[Boeing–Sikorsky RAH-66 Comanche]]
* [[Eurocopter Tiger#Tiger ARH|Eurocopter Tiger ARH]]
* [[Leonardo Helicopters AW249]]
* [[HAL Prachand]]
* [[Harbin Z-19]]
* [[TAI/AgustaWestland T129 ATAK]]
|lists=
* [[List of military aircraft of Japan]]
* [[List of rotorcraft]]
|see also=
}}

==References==

===Citations===
{{Reflist}}

===Bibliography===

* Aoki, Yoshimoto. "Kawasaki OH-1". ''World Air Power Journal''. Volume 38, Autumn/Fall 1999. London:Aerospace Publishing. {{ISBN|1-86184-035-7}}. {{ISSN|0959-7050}}. pp.&nbsp;36–45.
* Jackson, Paul (ed.) ''Jane's All the World's Aircraft 2007–2008''. Coulsdon, UK: Jane's Information Group, 2007. {{ISBN|978-0-7106-2792-6}}.
* Taylor, Michael J.H. ''Brassey's World Aircraft & Systems Directory 1999/2000''. London:Brassey's, 1999. {{ISBN|1-85753-245-7}}.

==External links==
{{Commons category|Kawasaki OH-1}}
* [https://www.mod.go.jp/gsdf/equipment/index.html#/detail/3/3_10/ Official JGSDF page]
* [http://www.khi.co.jp/english/aero/product/helicopters/oh_1.html Kawasaki Aerospace Division OH-1 page]
* [https://web.archive.org/web/20081004232617/http://www.mhi.co.jp/en/products/detail/ts1_turboshaft_engine.html TS1engine | Mitsubishi Heavy Industries, Ltd.]

{{Kawasaki aircraft}}
{{JSDF aircraft designations}}

{{DEFAULTSORT:Kawasaki OH-1}}
[[Category:1990s Japanese military reconnaissance aircraft]]
[[Category:Military helicopters]]
[[Category:Fantail helicopters]]
[[Category:Kawasaki aircraft|OH-1]]
[[Category:1990s Japanese helicopters]]
[[Category:Twin-turbine helicopters]]
[[Category:Aircraft first flown in 1996]]