Robot made of multiple rotor; Rigged with simple animation.
[now with bone rotational constraints]
I'm definitely a newb at blender. This is mostly just an exercise in rigging. For anyone else who is just learning blender you may want to consider looking at the following if you dl this blend:

vertex groups in the mesh;

bones (appropriately named after the corresponding vertex groups) in the armature;

limited rotational constraints (for almost every bone found in the bone constraints)