Ni akọkọ designated bi awọn YHO-6A ni ibamu si awọn Army ká designation eto, awọn ofurufu ti a redesignated bi awọn YOH-6A ni 1962 nigbati awọn Department of Defense da a Joint designation eto fun gbogbo ofurufu. marun prototypes won itumọ, ti ni ipese pẹlu a 252 shp (188 kW) Allison T63-A-5A, ati ki o fi fun awọn US Army ni Fort Rucker, Alabama lati dije lodi si awọn miiran mẹwa prototype ofurufu ti a gbekalẹ nipa Bell ati Fairchild-Hiller. nigba ti awọn ti idije, awọn gbekalẹ, awọn YOH-4, ti a ti yọ bi jije underpowered (o ti lo awọn 250 shp (186 kW) T63-A-5). awọn bidding fun awọn LOH wá si isalẹ si Bell ati Fairchild-Hiller.
Ọdún 1963