Hypothetically, I have built a practical, street-legal hovercraft, with all manner of lateral porting for stability in turns and for braking, and a segmented underbody for uneven surfaces, I about thought of everything. Except, to get across the river to the other side of town, I have to go twelve miles out of my way to where I can enter and leave the waterway at water level. Because, you see, there are six bridges across the river that I am leery of even trying.
The question is this: if my hovercraft is going, say, 30mph when it reaches the grating on one of these bridges, can I expect it to completely fail, crashing to the road surface and throwing me into traffic? Is there any speed or design that would allow it to get across an open, grated surface, or will it always have to take the long way around?
I think it would depend on the span of the grating and how fast you are moving. Maybe you could put some retractable wheels underneath to drive across the grating. They could also be deployed on tilted surfaces and during cornering to keep you from drifting. Kind of a best of both worlds hybrid.
Without some other means of support a hovercraft would lose lift over a grate and drop down nearly instantaneously. Probably before even half the craft’s length made it across it.
