Dangerous Top Heaviness

[NMMarauder]

I should have clarified that in no way was this meant to be a comprehensive analysis of tipping. It's meant to give you an idea of how "tippy" your build is in terms of some best case/worst case ballpark numbers. The only way to determine the maximum crosswind in which you can safely tow your trailer is to rent time at a wind tunnel facility with the tow vehicle you plan to use.

If the trailer is going to tip, sitting in your yard, in a 30 mph crosswind, then you might want to rethink your design. On the other hand, if it takes 100 mph or better to un-weight a wheel then I would rest a bit easier. Civil engineers deal with this more as they have to calculate the wind loading on structures. If you really want to dive into all of the quirks of how wind affects a static structure, then just google "wind loading". That's where the basic equations above come from.

The table of drag coefficients was literally the first search result that I found. It was meant to give a representative range of Cd. I'd say use the parachute or flat plate for a worst case scenario. When the trailer starts to tip the Cd would change anyway because an angled plate has a different Cd than one perpendicular to the flow.

As others have mentioned. The best idea is to not drive in high winds and secure your trailer to the earth well if you are expecting a hurricane to hit.

[NMMarauder]

One more thing that I find interesting.....

As far as a crosswind un-weighting one wheel, it doesn't matter how high the center of gravity of the vehicle is. What matters is how far the CG is away horizontally from the point about which it is tipping. How high the CG is only comes into play when the wheel has left the ground.

So in theory, loading more weight on the windward side will help with tipping. But that assumes that you tow on level ground and that the wind doesn't change directions 180 degrees. That's too many assumptions for my comfort zone so my recommendation is to build a load your trailer so the CG is close to the center-line of the trailer and low to the ground.