Improving AC-130H Gunship Performance Through Drag Reduction - A Wind Tunnel and Flight Test Partnership 1999-01-5506
Approximately 120 hours of wind tunnel testing were accomplished to determine the drag contributions of various external protuberances on the AC-130H Gunship and to recommend modifications to achieve optimal drag reduction potential. Also, the operational impact of the recommended configuration was quantified using a performance modeling code. The overall objective of this effort was to establish a solid foundation via experimental and computational ground efforts to support flight test of drag reduction modifications to an aircraft.
Thirteen basic AC-130H protuberances were evaluated to determine their incremental drag. A recommended reduced-drag configuration was developed which provided a drag reduction potential of 58.2 counts.
An Air Force Research Laboratory performance modeling code (CASP) predicted that the H-model gunship could save 1,630 lbs of fuel, increase its radius 57.4 nmi, or increase its loiter time by 30.0 minutes in a typical combat mission with the recommended modifications. Also, the two-engine absolute ceiling of the AC-130H was predicted to increase approximately 1,500 feet.
This research has successfully demonstrated the potential for significant drag reduction and operational improvements in the AC-130H. Verification through flight test is the next logical step before successful implementation.