High Power EM Field = Cooked
From the description of how the propulsion works:
If the two fields become mutually resonant, a vector force will be generated. Unless the amplitude and the frequency of the resonance is quite high, the vector field will be very small and may pass unnoticed. However, the amplitude of the vector field increases at a greater rate than the two fields which generate it and, at high resonance levels, becomes very strong. The vector field, whose direction is perpendicular to each of the other two, creates an effect similar to and in fact identical with a gravitational field.
If the center of the field coincides with the craft's center of mass, the only effect will be to increase the inertia or mass of the craft. If the center of mass does not coincide with the center of force the craft will tend to accelerate toward that center.
If the gravitational-like force is generated by high-power resonating fields, then the occupants of a vehicle would have to be enveloped in that field, right? The force certainly does affect the occupants:
"The answer is, of course, simply that the force which accelerates the vehicle, acts, not only upon every atom of the vehicle itself but also acts equally upon every atom of mass which is within it, including the pilot or passengers." (page 40, WSI)
The problem is that organic material inside a high power resonating EM field will heat. It works like this - all cells are made up of atoms that have a slight north and south magnetic polarization and if they are subject to a quickly alternating magnetic field, they flip back and forth. The stronger the field and higher frequency the field, the more quickly and faster they flip, heating up their surroundings. Inside a megawatt EM field, getting cooked would be a severe problem.
There is evidence to support the idea that the EM field is offset because the cargo craft has what looks like separate top and bottom sections. When the door of the cargo carrier was opened, it means that no resonance could occur inside the bottom half and yet the cargo carrier did not topple over. Fry described it as crushing bramble beneath it, but it did not put legs down on the uneven ground which likely means that it had not fully landed. If it had not fully landed, it means that the craft could hover while the door was open and must have had a source of EM resonance somewhere else in the ship, most likely in the top half.
Having separate resonating compartments makes sense from a redundancy perspective too, because if one compartment was damaged and could not support resonance, then the other half of the craft could be used. Resonance conditions, especially in extremely high Q cavities need very finely controlled tuning and having bodies or cargo inside the cavity would severely disrupt the resonant mode. The conclusion is that the artificial gravity force vector created in the top half of the craft also extended into the bottom half where there was no resonating EM field. The explicit assumption is that Fry was in the artificial gravity field, but it was generated above him in an electrically separate compartment by a resonating EM field.
- "the fact that the brush was crushed flat under it when it settled to the ground, Daniel Fry Dot Com, "White Sands Incident", page 18
- The correct mode would be necessary for both directional control and a high Q