Abstract: A solid rocket motor grain construction is disclosed for use in a ramjet to improve performance. The solid fuel burn enhancer adds oxidizer for burn rate control. Two constructions are disclosed. The inlaid approach places cores of solid low-oxidizer fuel within solid unoxidized fuel and the integrated approach provides shells of low oxidizer around the solid unoxidized fuel. The low-oxidizer fuel has a faster burn rate and smaller burn area requirements than the unoxidized fuel. During initial ramjet operation, when the burn area is constrained, the low-oxidizer fuel burns initially with its smaller burn area requirements. Subsequently, the conventional unoxidized fuel burns when larger burn areas are available.