Our 3D printed propeller blades are not as strong as we would like because they are printed perpendicular to their main surface if we don’t want to print supports that are time consumming.
5-axis 3D printing and conformal (non planar) slicing is possible along the main curved surface. Industrial solutions like the Vshaper do exist: 'VSHAPER 5AX - Professional 3D Printing five axis gamechanger! but at the price of 300,000usd.
For home users, a support-less 3D printing is now possible under 1300usd on a modified prusa mk3s+ (here using Rhino + GrassHopper)
The GitHub repository : 'https://github.com/FreddieHong19/Open5x
Non planar printing
Assembly of the 5th axis
3D printing a Helix