5*3" 2 bladed propeller (OpenSCAD) CW+CCW

A simple 2 bladed propeller with really nice blades copied from http://www.thingiverse.com/thing:172801

I've tried to copy the dimensions from a generic 5*3" propeller that I got from this set:
http://www.aliexpress.com/item/Mini-250-Quadcopter-1806-2280kv-Motor-12A-Esc-CC3D-Flight-Control-5030-Propeller-CC3D-Distribution-LED/32297309822.html

To get a (nearly) valid STL as the one you find under the "Thing Files" tab, you need to open the STL file you export from OpenSCAD in MeshLab and