Kawasaki OH-X / OH-1 / AH-2
Developed to replace OH-6Ds of JGSDF, the Japan Defence Agency (IDA) awarded Y2.7 billion (US$22.5 million) in FY92 to cover the basic design phase of the helicopter then provisionally designated OH-X.
Requests for proposals were issued by JDA's Technical Research & Development Institute (TRDI) 17 April 1992 and Kawasaki was selected as the prime contractor (60% of programme) on 18 September 1992, with Fuji and Mitsubishi (20% each) as partners. The Observation Helicopter Engineering Team (OHCET) was formed by these three companies, beginning with a preliminary design phase 1 October 1992. A mockup was made public on 2 September 1994 under the Japanese name Kogata Kansoku (new small observation [helicopter]).
The programme included six prototypes (four flying, two for ground test), and the first aircraft (32001) rolled out at Gifu on 15 March 1996 and made first flight 6 August 1996, followed by second prototype on 12 November. The OH-1 designation was assigned late 1996. The first two XOH-ls were handed over to JDA on 26 May and 6 June 1997. The third flown on 9 January 1997, at which time the earlier aircraft had accumulated some 30 and 20 hours, respectively. The third was handed over on 24 June 1997. The fourth was flown on 12 February 1997 and handed over 29 August 1997. The prototypes were renumbered by 1999 from 32001-04 to 32601-04.
The Japan Defence Agency's Technical Research and Development Institute was looking to develop an attack version of the Kawasaki OH-1 armed reconnaissance helicopter which in 1998 was at the flying prototype stage. Consideration was being given to replacing the OH-1's single Mitsubishi XTS1-10 engine with two LHTEC T800 or MTU/Turbomeca & Rolls-Royce MTR-390 turboshafts for the AH-2, together with a new gearbox and rotor system, plus a new integrated sensor targeting and weapon system.
The first three production OH-1s were funded FY97 and ordered in 1998. The first prototype was flown with more fuel-efficient TS1-10QT (replacing XTS1-10) engines, on 30 March 1998. By early 1999, four prototypes had flown 450 hours and were due to complete further 450 hours by end of 1999, including operational evaluation at Akeno JGSDF base. The first production OH-1 (32605) flown July 1999 and handed over to JGSDF at Gifu 24 January 2000.
Name 'Ninja' reportedly given in 2002, but not officially confirmed.
The OH-1 features Kawasaki hingeless, bearingless and 20mm ballistic-tolerant four-blade elastomeric main rotor and transmission system; Fenestron-type tail rotor with eight unevenly angled 'scissor' blades (35 and 55 degrees); stub-wings for stores carriage. Active vibration damping system. Flying controls are integrated AFCS and stability control augmentation system (SCAS). The rotor blades and hub are manufactured from GFRP composites; centre-fuselage and engines by Mitsubishi, tail unit/canopy/stub-wings/cowling by Fuji, rest by Kawasaki. Some 37% of airframe (by weight) in GFRP/CFRP.
The landing gear is a non-retractable tailwheel type, with provision for wheel/skis on the main units.
Power is from twin 662kW FADEC-equipped Mitsubishi TS1-10QT turboshafts (XTS1-10 originally in prototypes), and the transmission has a 30-rninute run-dry capability. Stub-wings can each carry a 235 litre auxiliary fuel tank.
The crew of two are on tandem armoured seats (pilot in front) with flat-plate cockpit transparencies, upward-opening on the starboard side for crew access.
Armament is four Toshiba Type 91 (modified) lightweight short-range, IR-guided AAMs on pylons under stub-wings for self-defence.
Funding for development, prototypes and flight testing Y2.5 billion in FY92, Y10.2 billion in FY93, Y50.1 billion in bY94 and Y23.3 billion in FY95. Unit costs of first four production lots Y1.924 billion (FY97), Y2.018 billion (FY9S), Y2.229 billion (FY99) and Y2.075 billion (FY00).
The Hiko Jikkentai (Flight Test Squadron) was formed at Akeno with first four production aircraft on 27 March 2001; other deliveries by late 2002 included small numbers to Kasumigaura Bunko, Utsunomiya Bunko and Kyoiku Shien Hikotai (at Akeno), all of which are departments of the Army's Koku Gako (Aviation School).
A total of 20, including prototypes, were ordered by FY02, and at least 12 delivered by late 2002.
Engines: s x Mitsubishi TS1-10
Main rotor diameter: 11.6m
Fuselage length: 12.0m
Height to top of rotor head: 3.4m
Height over tailfin: 3.8m
Empty weight: 2450kg
Normal take-off weight: 3550kg
Max take-off weight: 4000kg
Max level speed: 277km/h
Combat radius: 200km