I have found sometimes the experts make claims and print fancy graphs that simply are not correct. The reason could be they need to publish something to get paid. They cant publish a study that concludes the project is flawed.
For instance, I have a fancy paper from some engineering society that concluded ducted fans are better for small aircraft. But they never made a real test. The Wright brothers were aware of this problem so they built a wind tunnel to verify the claims of top experts about airfoil lift. They found the airfoil data to be overly optimistic.
NASA has been studying the "unducted fan" for years with claims of 20% fuel savings. Study after study.... But nobody wants to go back to props and NASA cant see the obvious sometimes. Thats why I asked for an objective opinion from the pprune readers. This is a pretty good way to get some varied opinions.
Then sorting through the opinions requires a basic understanding of physics. I work at learning the aerodynamic details. Only then can something new and "better" be created.
slowrotor