A couple of years ago, I started down the path of an auto conversion project and quickly became aware of the many design challenges, especially as regards torsional vibration, and the limited number of available options that are universally regarded as successful, safe alternatives. Lately, I've begun to question whether some kind of Open Source project couldn't be started that might, for example, put the best minds on this forum together to design three or four PSRU options for different horsepower ranges. For each horsepower range, the project could pick a suitable engine and propeller, detail the analysis process, create 3D design models (e.g., in SolidWorks), prepare manufacturing drawings and specifications, etc. Maybe the project could even do some crowd funding to support development of a prototype and some level of testing. The question isn't whether the talent exists on this forum, but whether there's (a) sufficient interest and (b) the right protections can be afforded the participants against legal liability in the event a design option is built, fails, and causes injury or death to someone, regardless of whether they adhered to the design/build guidelines or not. There are countless open source projects ongoing for software development and a number of organizations have emerged with specific licenses, contracts, disclaimers, etc. Does anyone here know whether similar projects and protections are available for hardware development?