Overview of the 1985 NASA Lewis Research Center SP-100 free-piston Stirling engine activities

An overview of the 1985 (NASA) Lewis Research Center free-piston Stirling engine activities in support of the SP-100 Program is presented. The SP-100 program is being conducted in support of the Department of Advanced Research Projects Agency (DARPA) and the Department of Energy (DOE), and NASA. This effort is keyed on the design, fabrication, assembly, and testing of a 25 kW(e) Stirling space-power technology-feasibility demonstrator engine. Another facet of the SP-100 project covers the status of a 9000-h goal endurance test conducted on a 2 kW(e) free-piston Stirling/linear alternator system employing hydrostatic gas bearings. Dynamic balancing of the RE-1000 engine (a 1 kW(e) free-piston Stirling engine) using a passive dynamic absorber is discussed, along with the results of a parametric study showing the relationships of Stirling power converter specific weight and efficiency as functions of Stirling engine heater to cooler temperature ratio. Planned tests are described covering a hydrodynamic gas bearing concept for potential SP-100 application.