I've driven my MG on the Formula One track at the Indianapolis Motor Speedway, as part of "Indy British Motor Days". They lined us up and told us to keep the speeds to less than 30 MPH, but everyone was giving lots of room between cars so you could floor it and get more speed. I probably got to 80 on the main straight-away, before the track dives into the infield in the series of hairpin turns. Through those flat turns, I could not keep the car from fish-tailing at anything above about 20. I got a real appreciation of the downforce it takes to hold the F1 cars on the track at higher speeds.

For the banked turns, Indy is considered a low-banked track, but you can really feel yourself being pulled down into your seat, even at low speeds with no aerodynamics. So the G-forces at 230 must be incredible.

As for a Tri-foiler, since it can't fish-tail as it turns, I can see it easily generating lots of G-forces, till it flips or something breaks.