It has always intrigued me why motors/props were so far forward on many of my planes. Engines for that matter too. I realise that we need to get a good CG balance , but many of mine seem to really be hanging further forward than they need to. I've not had much experience moving them , maybe only moving props a few mm forward or backward. Although one mount I installed on a nexstar mini-ep wound up being way further forward than stock. It crashed.

What started this was my e-stik may need a new motor and I like using lightest stuff available. Well it is one that actually hangs the motor out front with nothing else there. Given that I want to keep the same CG and motor weight I could conceivably mount the motor BEHIND the mount (instead of ahead of it) thus moving the prop back a few inches. I could then move the battery forward to keep same CG. I guess being a car/truck nut convinces me that all weight should be concentrated in the lowest center of vehicle for a good polar moment of inertia and handling.

Is it not the same with planes? (other than ability to be in many various orientations) Is there a significance to having the prop far away from LE of wing? I do have a couple of props behind the wing planes.

I notice that many of my planes have the battery exactly on the CG , yet some of them are very much forward of that point. Let's say I needed to install a heavier motor instead of a lighter one. Would I then be ok to move it far back? AND the prop?

Hope you kinda get what I'm asking and why. It doesn;t have to be very scientific.