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 apply the filter "Cleaning and Repairing" -> "Remove Duplicate Faces". This still leaves you with a few errors, but its close enough to be sliceable with Slic3r. see also: http://forum.openscad.org/Visually-and-by-inspecting-code-surface-looks-perfect-But-quot-Object-may-not-be-a-valid-2-manifold--td12686.html The first set of files I've uploaded is a CCW prop, now I've added a CW prop with a more sensible filename. They are lying upside down since on the downside the center ring hole is 1.5*1.5mm bigger then the rest of the hole (which is 5mm) which of course is better printable when this bigger hole faces up. The wings can only be printed with support material either way. UPDATE: Since this prop has much too little lift, I've created a new version with bigger wings, see files. To circumvent problems with the resulting STL files, I've instead based this new version on a cleaned up STL containing a single wing -> "mywing_ml3.stl" UPDATE 2015-05-31 today I've tested a few prints of the "big-wing" variant and unlike expected I got much less lift with it then the original design. Next I'm gonna try something much simpler: "redesigned-wing_2D_v3.stl" UPDATE 2015-06-01 Since by now I've printed and tested a lot of props (I'm trying to get usable propellers with which I can fly my quadcopter to bridge the time till my prop-shipment arrives) I've assembled a list with how much lift every print that I have tried gave me (meassured by strapping the quadcopter to kitchen scales, and just turning on the one motor by usign the cleanflight configurator motor test tool) original prop delivered with my quadcopter set -> between 280g and 300g "5x3prop_CCW" (first design) -> 135g "big-wings_v2" -> 60g "redesigned-wing_2D_v3" -> 170g "prop5x3x2_v7" -> 207g "prop5x3x2_v8" -> 158g "prop5x3x2_v8" after bending the rear ends of the wings down (with a soldering iron heated to 190°C and a flat ending) -> 184g "prop5x3x2_v9" -> around 230g I've stopped work on this project, since my delivery of replacement props finally arrived ;) If you're interested in the story "behind" these propellers, see http://koega.no-ip.org/mediawiki/index.php/Building_a_quadcopter