*The F-35B is a short take off/vertical landing (STOVL) version intended primarily for the USMC as a replacement for the AV-8B Harrier. It is this variant which has had the most difficulties in testing and later in production, due to the technical requirements. | *The F-35B is a short take off/vertical landing (STOVL) version intended primarily for the USMC as a replacement for the AV-8B Harrier. It is this variant which has had the most difficulties in testing and later in production, due to the technical requirements. |