Offset a force

Hi,

I'm somewhat new to unity and game making in general, but I managed to put controllable forces on my rigidbodied camera so I could simulate the view of an helicopter. The problem is that I've got to apply the lift force higher than the center of my camera so it can simulate a real chopper, the rotor of a chopper being located over the body. It seems impossible to apply an offset with rigidbody.addforce.

I tried to put an empty rigidbodied object over the camera, make it child of the camera and apply the force on it, but the "chopper" just falls when I test.