TEST AND EVALUATION OF THE REVERSIBLE CONVERTER COUPLING REVERSE REDUCTION GEAR

Abstract

ABSTRACTThe Reversible Converter Coupling (RCC), designed and manufactured by Franco Tosi Industrial of Italy, underwent testing at the Naval Ship Systems Engineering Station (NAV‐SSES) Philadelphia, Pa. in March 1984. The Franco Tosi RCC concept can be simply described as a conventional hydraulic coupling (i.e., input or pump rotor driving an output or turbine rotor) with a set of stationary blades that can be inserted between the two rotors to reverse the fluid direction and hence the output rotor direction. The purpose of this testing was to test and evaluate a main propulsion reverse reduction gear concept, using the Franco Tosi RCC, for its compatibility and applicability to gas turbine propulsion machinery configurations, specifically the AOE‐6 class ship. Satisfactory development of a workable and reliable reversing system permits use of a fixed pitch propeller.The RCC models tested were the Original Type “79,” the Type “79” Prototype, the Type “79” Production, the Type “84” Production, and the Type “84A” Production. A series of tests was conducted to verify rotor integrity, determine RCC efficiency, evaluate machinery interface, and to determine the overall characteristics of the RCC design. Testing revealed that the Type “79” Production RCC was the most suitable for application on gas turbine powered main propulsion systems. The Type “79” RCC design was approximately 10 percentage points higher in astern efficiency than the Type “84” design and, although the structural integrity of the Type “84” design was superior to the Type “79” design, the Type “79” Production RCC was satisfactory for its intended use without introducing any operational restrictions.The Naval Sea Systems Command approved the Type “79” Production RCC for the AOE‐6 class ship in April 1986, based on the information acquired during testing.