Staff Writer (Updated: 3/28/2015):
Externally, the Kiowa presents a streamlined and lightweight form. The cockpit is held well-forward on the fuselage and seats the pilot and co-pilot/observer. The cockpit provides for excellent forward viewing thanks to its large forward windscreens and removable automobile-style hinged side doors. To the rear of the cockpit is the passenger cabin that sports exit-entry doors and room for an additional two or three personnel or two medical litters. The engine is mounted atop and to the rear of the passenger cabin, powering the main rotor blades. In the OH-58D model (detailed below), the identifiable Mast Mounted Sight (MMS) is installed atop the main rotor mast. The slim empennage extends out from the rear fuselage and fits a pair of horizontal planes midway aft. At the extreme end of the empennage is a vertical tail fin facing starboard and the two-bladed tail rotor facing portside. The Kiowa does not have a standard powered wheeled undercarriage but instead makes use of a rather traditional and simplistic heavy duty landing skid system braced at two positions along the fuselage underside. The aircraft's inherent quick set-up capabilities require a preparation time of just ten minutes from unloading to flight.
The Kiowa was originally known under the Bell model designation of "206A" and first flight was recorded on January 10th, 1966. Production of militarized Kiowas began that same year and would run into 1989, covering various types and marks to suit mission need, technological advances or customer requirements.
The initial OH-58 production model became the "OH-58A" which was a dedicated light observation platform with seating for four and was only partially armed when it saw service in the Vietnam War. Armament could be either an M134 Minigun or M129 40mm automatic grenade launcher and was consistent with weaponry as found on other armed US Army helos in the conflict. The OH-58A was also accepted into service with the Canadian Army and these took on the designation of "COH-58A", later becoming the "CH-136". The OH-58A was fitted with a single Allison T63-A-700 series turboshaft engine of 317 shaft horsepower which provided for a top speed of 138 miles per hour and a cruise speed of 117 miles per hour. Range was out to 300 miles with a service ceiling of approximately 19,000 feet. "OH-58B" was used to designate export models for Austria.
OH-58Cs were given a more powerful engine, IR suppression and revised forward windscreens. Its cockpit was also redesigned to an extent and night vision support was introduced. The OH-58C models were also the first of the lineage with provision for the short-ranged AIM-92 "Stinger" anti-aircraft missile to which a pair of these could be mounted along hardpoints at the fuselage sides. This provided for a mobile air-based enemy aircraft/helicopter deterrent for cavalry forces lacking such defense.
The OH-58D became the definitive mark of the Kiowa production line, first flying in prototype form on October 6th, 1983. The OH-58D arose out of the US Army's "Army Helicopter Improvement Program" (AHIP) of 1979 to which Bell faced off against a modified Hughes OH-6 Cayuse. Bell ultimately nabbed the defense contract and the OH-58D legacy was born, the aircraft entering service in December of 1985. It was given a new engine and gearbox as well as a four-bladed main rotor assembly (previous versions only fielded a two-bladed system) and was intended as an unarmed scout. The most distinctive feature of this model mark became its McDonnell Douglas Astranautics Mast Mounted Sight (MMS) which appeared as nothing more than a sphere atop a mast which was fitted atop the main rotor mast. The MMS itself was a collection of equipment and lenses encompassing a laser range-finder / laser designator, thermal imaging and television optics. Internally, crews were greeted with an upgraded digital cockpit that introduced Multi-Function Displays for both cockpit positions. In fact, the OH-58D became the first US Army helicopter to field an "all glass" cockpit. Interestingly, the old-style analog gauges and instruments were retained in the event of a failure to the digital wares. An APR-39 indicator could alert pilots to enemy guided missile launches directed at the aircraft. The pilot and co-pilot positions featured redundant controls as in most helicopters.