Tracks Upside down track

[ltcars]

There are some cars in AC which have enough downforce to drive theoretically upside down. Would it be possible to make some sort of tunnel where you can drive upside down?

 

[garyjpaterson]

There are some cars in AC which have enough downforce to drive theoretically upside down. Would it be possible to make some sort of tunnel where you can drive upside down?

I think there could be issues in the transition - IIRC, AC struggles with high gradient surfaces.

 

[ltcars]

But driving 180° flipped would be possible surface wise?

 

[Joseph Maxx]

Not sure if it has changed but it used to reset to the pits after 3 seconds if the car was upside down

 

[garyjpaterson]

In the respect of aero, yes, there are loads of cars that produce more than their mass in downforce at certain speeds. But in terms of the driveable surfaces working in AC at 180°? Not sure, never tried it.

Not sure if it has changed but it used to reset to the pits after 3 seconds if the car was upside down

There is an option in the .ini files that lets you turn that off - that option used to be bugged but it works now.

 

[AccAkut]

I'm pretty sure AC does no ground collision above ~50° angles. There is/was half a loop on stereos testpad track, and you would just fall through it halfway up.

 

[Deleted member 130869]

What if you make it as a Stunts-like tunnel, so you progress sideways and going straight ahead at all times instead of going on a loop?

 

[LilSki]

Never going to happen. AC simply will not register a driving surface past a certain angle. You will never even get close to 90* no matter if it is a loop or a tunnel.

 

[dud]

There also is a problem with traction. Even if you have more (now inverse) downforce than weight, you would need to maintain a very high speed, overcoming the air drag. You might not have enough tire contact to do so. Tiny bumps will also have something of a "moon effect", have you floating over (now under) the surface much longer than normal. If during such time drag slows you down too much you drop. Underbody and rear diffuser downforce would drop severely on bumps.

 

[Stereo]

I've tried doing it on a barrel roll style track in another sim and the problem (with an F2004, so rwd) is that you need enough grip to overcome drag easily. Otherwise the rear tires have high slip ratio and when your car goes up onto the vertical bank it starts to spin out. So just having more downforce than the car's weight isn't close to enough, you need downforce to exceed weight + drag by a decent margin.

Doing a vertical loop has the obvious problem that the smaller it is the heavier vertical G's you get (and front/rear of the car dig into the surface) but the larger it is the more you decelerate on the way up it.

So ideally you want a car that hits 'more downforce than its weight' at a speed where it's still accelerating easily. I don't think any real world cars get near that. Maybe boost turned up group C when they had full underbody tunnels allowed.

Probably the easiest way to do it IRL is to have the car riding upside down on a cart with its wheels against the ceiling and then have the cart drop away, it skips trying to get it up there, problems with the engine running upside down, etc.

 

[mclarenf1papa]

I've tried doing it on a barrel roll style track in another sim and the problem (with an F2004, so rwd) is that you need enough grip to overcome drag easily. Otherwise the rear tires have high slip ratio and when your car goes up onto the vertical bank it starts to spin out. So just having more downforce than the car's weight isn't close to enough, you need downforce to exceed weight + drag by a decent margin.

Doing a vertical loop has the obvious problem that the smaller it is the heavier vertical G's you get (and front/rear of the car dig into the surface) but the larger it is the more you decelerate on the way up it.

So ideally you want a car that hits 'more downforce than its weight' at a speed where it's still accelerating easily. I don't think any real world cars get near that. Maybe boost turned up group C when they had full underbody tunnels allowed.

Probably the easiest way to do it IRL is to have the car riding upside down on a cart with its wheels against the ceiling and then have the cart drop away, it skips trying to get it up there, problems with the engine running upside down, etc.

Late Group-C could probably do it. 850 kg with a driver and fuel, 8+ coefficient of lift, and 5-6:1 L/D ratio...the speed at which mass equals downforce is quite low, so maintaining something a decent amount faster would be pretty manageable.

 

[dud]

Well, we could always edit the car data to have 2x weight downforce, at a speed where subtracting the potential energy to reach the ceiling is still enough. But I believe the above warnings about AC game mechanics are correct.

 

[isamu]

In the respect of aero, yes, there are loads of cars that produce more than their mass in downforce at certain speeds. But in terms of the driveable surfaces working in AC at 180°? Not sure, never tried it.



There is an option in the .ini files that lets you turn that off - that option used to be bugged but it works now.

Is there an option to have the game reset your car back to the track at your *current* location on the map ala GPL?

 

[garyjpaterson]

Is there an option to have the game reset your car back to the track at your *current* location on the map ala GPL?

No.

 

[Guillaume Francois]

We can't race upside down track ? I'm doing fine at barthurst

 

[marksmellsdrama]

There are some cars in AC which have enough downforce to drive theoretically upside down. Would it be possible to make some sort of tunnel where you can drive upside down?

I put a car upside down in a loop bro, it's possible, here's proof:

 

[Stereo]

This thread's from 2018, CSP added a replacement tire raycast method that can run on walls/ceilings, so as long as you're using a car that enables that, it works. I believe @mclarenf1papa has done barrel rolls in my test track with it. The vanilla raycasts always go straight down and ignore stuff that's too steep (idk for certain why that is, but it's a racing simulator so maybe it just never came up)

Also clarifying a couple points on your video
- your first loop doesn't work well because you have two collidable ground objects stacked (loop over grass), within a fairly large margin, that's going to cause the tires to "see" the lower of the two. I haven't tested exact limits but have heard of issues with up to ~2m height difference. The ~50 degree angle seems pretty accurate once you avoid that.
- WALL objects collide with cars but not tyres, it's fine for doing a vertical loop but you can't drive upside down (goal of this thread)