4045 3-Blade Propeller

thingiverse

That's a propeller designed to be 3D printed with precise details that require some effort to perfect. To get it right, you'll need to add support structures and do some fine-tuning. But if you print it upside down, you'll save time and reduce the number of supports needed. The design is available in clockwise (CW) configuration; simply flip it over in your slicer to get the counterclockwise (CCW) version.