Does not need bones

1.What is the best way to work with imported elements in UE? Can I animate position and rotation of the elements in there or would I better animate externally and import the animation as FBX? If so, how do I start the animation in UE?
2.I have a drone to be controlled, and his joints are mechanical that means he does not need bones
how can I import it into the UE4 and control it there too ?

Ps.I have made an example for you

234634-gifmakerorg-evxzr9.gif

I made a drone a while back and my approach was to rig and skin it within an external tool, and import it as a skeletal mesh, all the animation was driven by code though rather than baked animation.

As you can see I was running 4 propellers through an external variable

I also had a gun mounted that follows a target using the Look At node, that was fed in externally as well.

My rule of thumb when it comes to animation, (and this is by no means how everyone works just the way I like to) is that if it only has single degree of movement on a bone then it should always be animated in code. This makes iterating quicker and takes some pressure off your animators.

oh thanks a lot
that is very helpful for me thanks