The Navy asked Gyrodyne to develop an Allison powered YQH-50E when Boeing ceased building its 365 shp model 550-1 turbo-shaft engine (military designation T50-BO-12) in April 1968. Under Naval Air Systems Command Contract No. N00019-69-C-0361, dated 31Dec68, Gyrodyne modified three QH-50D to YQH-50E test vehicles. The initial Allison T63-A-5A, Model 250-C19A, free turbine type, gas turbine engine used in the YQH-50E, was rated at 317 SHP at sea level. When tests demonstrated dramatically improved performance, Gyrodyne proposed a remote controlled VERTREP QH-50E platform, capable of hauling 1,500 pounds of cargo; or other sensor packages or weapons loads.
US Navy 