This is our solution to protect the Crazyflie2 from crashing against obstacles. It must be printed out four times, one for each rotor. Each protector can simply be plugged on a motor. Just remove the motor from the case for that. After you printed it out, take care that all connections were printed well. We had some prints which were not stable - one-second-glue is the solution ;-) Have fun! http://fred-project.github.ioWe looked at similar models for the CF1 for the basic architecture and measured the CF2 to adapt this idea to the newer version. That's what came out.