The minimum height I get is 2.5R. So if the loop is 4 meters high (with a radius of 2 meters), the car would have to start 5 meters above the ground Now! Make a loop. Of course, this assumes that there is no energy loss due to friction; You might want to start a little higher to account for this.
But not very high…
In fact, why cut it close? Why not start now? excess Higher and remove all doubts? This is because the faster the car goes, the more g-force the driver experiences in the loop.
Let's think about this: if you leave a car so that it goes around the loop at minimum speed, this will happen Zero force from track (FTeaYou'll feel weightless—zero grams—for a moment. If the car is released from a height greater than 2.5R, its velocity will be greater than the minimum at the top of the loop. Still, to rotate in a circle, the force of gravity will not be enough. The track must also push the car down. This will produce a G-force greater than zero.
let's go back real stunt videoBy comparing the loop to people standing nearby, I'm estimating its radius to be 2 meters. The car is clearly released from a height of more than a minimum of 5-metres – let's say 8 metres. The force at the top of the loop (divided by the weight, to get it in g) will be 3 grams. Its It is possible for humans to tolerate up to 20 grams.So it should be fine.
But if you overdo it? If you start too high and make the loop too small, bad things can happen. What about a height of 20 meters with a 1.5-meter radius for the loop? This will generate a force of 21 grams. It may feel good, but it can also kill you. That's not fun anymore.