Update 5/15/18: The latest version of these pods are designed to be as light as possible, strong and adjusted for the thrust line. I've raised the position of the motor by about half an inch so that the plane tracks better when under higher throttle settings. For best performance, use "engine pod -7 m and p and mirror the models in your slicer for the other side.
Update 5/1/18: Just added a two piece pod so that the motor can be removed from the plane more easily.
Flite Test Dart model airplane engine pods. Mirror the pod for the second side.
Probably shouldn't use PLA since the engines get pretty hot. I'm using PETG on this first set.