I have figured out how to apply forces, mostly. For some reason setting persistence to false was failing to clear the external force each physics frame so I had to clear it manually.
Source code: https://gitlab.shihogan.com/JHLeonard/drones/-/tree/br0003
The "drone" now has four "propellers" at each of its corners. Front left can be powered by holding 'Q', front right with 'W', back left with 'O', and back right with 'P'. The front left and back right "propellers" apply a counter clockwise torque to the "drone" while the others apply a clockwise torque. You can still press 'R' to reset the "drone" when you inevitably flip it over.