Hello
The US Armed forces needed a light aircraft that could fulfill some different missions; one of the requirements was that the aircraft could and take off vertically but also had a reasonable flight speed to reduce transit times.
Bell proposed the OV-25 Grasshopper and that was the winning design.
It entered service with all the branches of the US military and was also exported.
The Grasshopper was used as a reconnaissance, battlefield surveillance, FAC, medevac and other roles.