OH-58 Kiowa

The Bell OH-58 Kiowa is a single-engine, single-rotor light observation and armed reconnaissance helicopter built by Bell Helicopter for the United States Army. Derived from the Model 206A JetRanger, it entered service in May 1969 and reached South Vietnam three months later. It is known for the mast-mounted sight fitted to the OH-58D Kiowa Warrior and for the knife-like wire strike protection extensions above and below the cockpit. The US Army withdrew its last examples in 2017.

Development

The design originated as the Bell D-250, submitted to the US Army Light Observation Helicopter competition initiated by the US Navy in October 1960. Designated YOH-4A, the first of five prototypes flew on 8 December 1962, but the Hughes OH-6 Cayuse was selected in May 1965. Bell reworked the fuselage, adding 16 cubic feet of cargo space, and marketed the result as the Model 206A JetRanger. When the Army reopened the competition in 1967 after Hughes failed to meet production commitments, Bell underbid Hughes and the 206A was designated OH-58A. Advanced Scout Helicopter work begun in 1974 lapsed when Congress declined FY1977 funding; the requirement resurfaced in 1979 as a near-term scout modification effort and became the Army Helicopter Improvement Program. Bell's Model 406 won the development contract in September 1981, first flew on 6 October 1983, and entered service in 1985 as the OH-58D. From the 202nd aircraft in May 1991 all were built in Kiowa Warrior configuration. Production totalled 2,325 airframes plus 56 Bell 206B-1; A and B production ended in 1977, D production in 2000.

Design

Early Kiowas used a two-bladed main rotor; the OH-58D introduced a four-bladed composite rotor and the first all-composite rotor hub on a US Army helicopter. The OH-58A was unarmed and weighed 1,451 kg fully loaded; the OH-58D has a 2,495 kg gross weight and a Rolls-Royce T703-AD-700A of 650 shp. The Ball Aerospace mast-mounted sight houses a television system, thermal imager and laser rangefinder/designator on a gyro-stabilised platform, with target data passed via a MIL-STD-1553 bus. Other features include NVG-compatible lighting, ballistic floor armour, crashworthy seats, infrared exhaust suppression and a missile warning system. The OH-58F replaced the MMS with the chin-mounted AAS-53 Common Sensor Payload.

Armament

The Kiowa Warrior carries universal weapons pylons on both fuselage sides. Loads include AGM-114 Hellfire missiles, AIM-92 Stinger air-to-air missiles, LAU-68 seven-round pods with Hydra 70 or APKWS rockets, and the M296 or M3P .50-calibre machine gun. Vietnam-era OH-58As were fitted with the M134 7.62 mm minigun.

Operational History

Around 45 OH-58As were lost in Vietnam to combat and accidents. Armed OH-58Ds of the 118th Aviation Task Force flew tanker escort from mobile sea bases during Operation Prime Chance from February 1988. During Desert Shield and Desert Storm, 130 OH-58Ds flew nearly 9,000 hours at a 92 percent mission-capable rate. Over 35 airframes and 35 pilots were lost in Iraq and Afghanistan, where the type accumulated 820,000 combat hours by April 2013. National Guard RAID units operated 116 modified OH-58As on counter-drug work. Exports went to Austria, Canada, Croatia, the Dominican Republic, Taiwan, Saudi Arabia, Tunisia and Greece, with 74 built as CH-136 for Canada and 56 as CAC CA-32 in Australia.

Variants

• OH-58A: Initial four-place observation model with two-bladed rotor, unarmed in standard configuration.
• OH-58B: Export version for the Austrian Air Force.
• OH-58C: Re-engined variant with flat-panel windscreens, AN/APR-39 radar warning receiver and NVG-compatible instrument panel.
• OH-58D: AHIP rebuild with four-bladed rotor, mast-mounted sight and glass cockpit, armed as the Kiowa Warrior.
• OH-58F: CASUP upgrade with AAS-53 chin sensor, Control and Display Subsystem 5 and Level 2 manned-unmanned teaming; first flight 26 April 2013.