After countless attempts to get one node to orbit another using simple mechanics I have stumbled into too many limitations of scenekit which just makes it more complicated.

I have now bit the bullet to make it completely physics based. 

I am looking to setup a physics world that all that is needed is one node to orbit another with the orbit radius to be adjustable. Gravity is not a must in this project if that would simplify the process. 

My attempts at this haven't resulted in what I am after. I am at a loss to what force to apply to achieve this. I have tried a multitude of different combinations of force, torque and gravity.

Note: I have looked at other questions and researched for quite some time, but all answers depicted a much more complicated physics world than is needed and/or needed a physics degree to understand.