After reading this thread, I want to check a rumor I heard: is it true that some open-wheel racecars generate so much downforce from their aerodynamic design that they could theoretically drive on a down-facing surface? I’m imagining some kind of Möbius-track here. :eek:
In theory, yes, it’s true. (Last line of the first paragraph). The official F1 site agrees.
I suppose it’s worth noting that it’s only the aerodynamics that allow upside down driving - the fuel, coolant and other liquids that need to circulate might not co-operate, which might be part of the reason no one’s tried it.
Other problems: ensuring the corners are fast enough to maintain downforce, plus the tricky issue of what happens when you overcook a corner and shunt the car (or just spin out.)
So it sounds as if the car would have to be specially designed for it–gravity-independent engine, ejectable driver pod with parachute, etc. But damn, that’s cool. If I ever get insanely rich I’m going to start a Möbius racing league. 
Could be done by banking the corner.
We’ve been over this before, and it’s not as easy to calculate as it might first appear. A F1 car on a normal (right-side-up) track does indeed produce a downforce greater than its weight. But the downforce produced depends in part on the speed, and the maximum speed depends in part on the normal force between the tires and the track (which is why they have the wings in the first place). On an ordinary track, the normal force is equal to the aerodynamic downforce plus the weight, but on an inverted track, the normal force would be the aerodynamic force minus the weight. This would mean a significantly lower normal force, which would mean a significantly lower maximum speed, which would mean less aerodynamic force, etc. So it’s possible that the car would not be able to maintain the necessary aerodynamic force on that inverted track.
Could they test this on a threadmill that turned with the car at top speed?
Nope. Cuz if the car wasn’t moving, it wouldn’t be generating them aerodynamical forces.
Right?
But if a duck was driving, you could measure the timing of it’s quack’s echo, and determine the distance to the wall.
Just don’t try to fire the 1920’s style death rays at the bottom of the Marinaras Trench, OK?
What’s a “threadmill” and how does that workin F1 racing?
I am glad you got the whole thing out of the way in a single post. Now back to our regular programming
A “threadmill” is when we keep posting and posting and posting but the discussion doesn’t go anywhere. It does leave the ground sometimes, though.
That only applies to curves, though; if you were travelling on a quick straight section upside down, the speed is independent of the normal force. I wasn’t visualising a whole race upside down, just a quick section of it (say while going through a straight tunnel; drive on the roof instead of the road). But you’re quite right about the maximum speed being limited by downforce on curves.
I think you miss **Chronos’ ** point. There is also the question of having sufficient traction to overcome friction to maintain speed. Imagine this theoretical scenario (figures purely illustrative): an F1 car produces downforce equal to its own weight of about 600kg at say 200km/hr. So at 210km/hr it might be producing say 601kg of downforce and so you might say it will be able to proceed upside down. But that 1kg net force up is not going to press its tyres onto the road with sufficient traction to overcome 210km/hr’s worth of drag. So the tyres will slip, it will slow down, and fall.
So you say: increase the speed to 300km/hr, and then perhaps it will produce say 1200kg of downforce, or 600kg net upforce. But is 600kg sufficient to press the tyres onto the road hard enough to get traction sufficient to overcome 300km/hr’s worth of drag?
It would be a matter whether you can find a speed that produces enough downforce to give the tyres sufficent traction to overcome the drag necessary to maintain that speed.
I had indeed. Thanks for pointing that out. I was only considering downforce required to corner, not to produce friction necessary to maintain straight-line speed. Makes sense though; although perhaps that would be moot if, say, F1 cars were powered by jet engines. That would solve that particular problem. 
It’s any thread where treadmills are mentioned - the argument starts going round and round very fast, but never takes off.
Causing friction, flames and a pit.
Since we are discussing F1, though, wouldn’t friction and a pit-stop be good things? Flames, now flames aren’t quite as welcome.
Wait – I thought it does take off!
But you could build a banked track that is mostly right-side-up, but includes a barrel roll so that the cars are not inverted for enough time to lose their speed?
Of course, that could work even with a normal car given a tight enough roll. So in an F1’s case, could you stop the track at the high point of the roll and continue it upside-down for awhile, then after X00 feet, turn it back right-side-up again to let them recover their speed?
Maybe a giant Hot Wheels loop-the-loop track.