I spent some time over the weekend designing this prop protector for a 3DR quadcopter. So far it's 90% done, I just need to design a little mechanism to lock it into the arm. It's too big for my 3D printer so I'm probably going to separate it into 4 pieces that lock in with glue. Once I have the full product done I'll probably order them through Shapeways so I can get them in once piece (a little hard to get around the prop though). I'll update how it's going and if anyone wants the file to made changes and help me prototype just ask.