Like this one.
As I was watching my six year old son play with his Hot Wheels, a though occurred to me: has a real, full-size car or motorcycle ever gone through a vertical loop?
Yes for a motorcycle. In fact now there are people who do 2 backflips on a MC in the air, not on a track.
Yes.
IIRC, there was no stunt driver:the car was under remote control…not out of fear of the car falling, but due to the rapid change in G-forces.
I thought vertical loops for motorcycles were a pretty common trick. I have seen many of them in person in circus type acts in specially designed cages and even more on TV. I have never witnessed one with a car though but it should be roughly the same idea but the setup would have to be much larger and elaborate.
Here is one example:
Here is another:
I had an '86 model and that stupid computer had to be replaced twice. Plus it didn’t function properly during Wisconsins cold winters!:mad:
Why would the G-force be any stronger than that felt on a big roller coaster?
Rollercoasters are designed to go upside-down, cars aren’t.
If you theoretically built a roller coaster track that used a car (maybe with different wheels), I don’t see why it wouldn’t be much different. Cars can sustain lots of g-forces. The upside-down part has little bearing on the issue unless you are just referring to engine function which may or may not be any issue with fuel injection and a fairly fast vertical curve.
Yeah, isn’t the whole idea that centrifugal force essentially simulates gravity? Even supposing you need 1g to operate, and keep a constant speed, to get 1g at the top you only need 3g at the bottom. According to wikipedia, a typical person can handle 5g before passing out. Might not be pleasant, but you could do it.
If you’re a fan of that sort of thing, I recommend you try out Trackmania, where loops are standard.
If the g-force at the top is keeping the car on the track (something that’s not tough to arrange), then the engine will be fine - indeed it won’t have any way to know it’s momentarily upside-down.
The same is true for airplanes. The stresses involved in a properly executed loop are mild and almost any airworthy aircraft is capable of this. Sustained inverted flight requires special engine adaptions, but in a simple loop the engine is experiencing something not far from what it does in straight-and-level flight, so it has no problems.
Fighter pilots can go much higher than 5 G before passing out. They are usually trained up to 7G and after that it start to result in red-out but blackout takes even more G’s for a well trained and fit person. I have experienced 3 G’s+ for a sustained period and it feels strange but it won’t hurt any healthy person.
Do it with a lion. I dare you. I double dog dare you.
Because of the shape of the loop. It needs to be more teardrop shaped (clothoid loop) so the bottom of the loop is much shallower than the arc at the top. The top of the loop is met at a slower speed and thus less G-force.
You can do it on a skateboard. Car or motorcycle is easy. 
Okay, let’s say I had fifty million dollars and the use of the Grand Canyon. Could I build a Hot-Wheels-style track that would let me loop a car?
If it is not in the database, it does not exist.
IIRC Formula-1 race cars, at speed, create enough downward force from their airfoils that they could, in theory, drive upside down around a track (as long as they didn’t slow down).
Linky no worky.
That proves it can be done but they were making too much out of the g-forces and it causing the driver to black out. The human body can take g-forces a lot higher than 6g for brief periods of time. He was already committed to the track once he entered the loop anyway.
And they didn’t need fifty million dollars either! Or the Grand Canyon.