A number of people have asked about adapting the Delta V15 props to fit the motors. I've added photos and a description to the wiki. Laser-cut prop adapters will ship with all the kits.
What is the hub length of the propeller? Can I use adapters like these? http://www.dx.com/p/r-c-plane-3-0mm-motor-shaft-propeller-prop-adapter-5-pack-82424#.U-ER4uOSyQA