News of this may get Lionel Ritchie dancing again.
All it’s really got to do is last 5 seconds. I wonder if they could do something like use the oil and fuel pumps to pressurize reservoirs that would act like buffers for 5 seconds of inverted use.
Five seconds full inverted, but some time – 5 or 10 seconds? – before and after, along the side of the tunnel.
Is the oil system “wet sump” or “dry sump” on an F1 engine?
Wouldn’t the C-shaped road be a potential issue?
The downforce comes - as I understand it - from scooping the air up from the nose and over the back. If you’re on a flat road (which our cars are designed for) then it’s best to have a nose that’s flat with that flat road. And if you were to drive on a concave road, then you would prefer to have the front of your nose be a concave shape?
I’m sure that the overall shape of the car has more to do with the matter than purely the inch or two gap between the nose and the surface of the road. But I’d want to double-check the difference before trusting my life on the question. 
ISTM that a lot of the issues people are raising here are answered, at least partially, in the video.
I’m at work.
On thinking about it some more, no car that’s properly engineered for upright high-speed driving would be able to drive upside-down. They build them with the amount of downforce they do because that’s the amount they can make use of. If you take a car engineered to be able to drive upside-down, and turn it upright, it’ll now have significantly more normal force and hence traction, and the engine won’t be sufficient to make use of that additional traction.
Agree, but with a caveat. Downforce has two purposes.
The obvious one we’re all thinking of is enabling the driving tires to convert axle torque to forward motion by having enough friction with the track to absorb all the power the engine is putting out. Whether to accelerate, or to maintain max possible engine torque/RPM-limited speed.
Reduce downforce in that scenario, whether through lesser wings or through being on a tilted or inverted surface, and now the tires can’t absorb all that engine power without slipping. The total normal force is aero-downforce plus Earth’s G. Driving on tilted or inverted tracks doesn’t (immediately) change the former, but does change the latter. Which, through inability to maintain top speed with reduced traction, may well reduce the former too.
As you’ve said.
But there’s another factor: curves.
Part of the function of downforce is to enable turning. A lot of F1 is about aggressive cornering, not about winding out the vehicle to redline RPM in top gear on a long straight. Which is the limit case for desired downforce for a pure dragster. but F1 isn’t a drag race. A car that weighs, eg. 800kg but has 1,800kg of normal force providing traction can corner like crazy. And does.
To the degree the typical downforce of an unmodified F1 car is about max-performing mid-speed cornering, there’s probably excess downforce at top speed straightline ops. If the rules permitted moveable wings they could be adjusted for less downforce in that straightaway case.
F1 doesn’t now allow moveable wings. But I do remember the dynamic wings on the early aero-cars of the 1960s and how they utterly changed the game. This car, being a demonstrator could incorporate that feature but probably doesn’t need to.
Anyhow, for this demo where the F1 car will be operating inverted on a straightaway, the stock vehicle may well have enough, or almost enough, downforce despite Earth’s G pulling in the wrong direction. To the degree they are only being inverted briefly, they can even afford to lose some speed while inverted as long as the corresponding reduction in aero-downforce doesn’t get critically close to the car’s weight.
For sure once the car gets to “weighing” just a handful of kg against the roadway it’s simply ballistic looking for the place it’ll crash.
Ah, true, I hadn’t considered centripetal force. How important that is would depend on the typical radius of turns on an F1 track, as well as the typical amount of banking on those turns, neither of which I’m familiar with, but I can easily buy that it might be more important than the straightaway.
F1 tracks have turns in both directions, right? If they were like NASCAR and always turned left, it might be worthwhile to put the wing at a slight (fixed) angle, but that wouldn’t work if you need to turn both ways.
F1 is non-banked and both lefts and rights. Not uncommonly they’re run on course made up of city streets with temporary jersey barriers to keep the cars out of the spectators and adjoining buildings. Lotta very tight radii and accelerating from 30mph to 150mph & back down.
Yes. F1 cars are designed to lap a track in the shortest possible time. At certain tracks which favor straight-line speed, the teams will configure their cars with less downforce; that increases straight-line speed at the expense of cornering speed. This was particularly true at the old Hockenheimring, where the cars’ rear wings were obviously smaller than at other tracks. It’s noticeable in Indy cars, too; they run smaller wings at oval tracks than they do at road courses.
In any case, the downforce is for turning, not straight-line acceleration and top speed.
Actually, they do. F1 introduced the Drag-Reduction System (DRS) in 2011. Under certain conditions, the driver can move one of the elements of the rear wing in a way that decreases downforce and drag. I suspect it’s designed in a such a way that if the mechanism fails, the wing reverts to a fail-safe, high-drag position.
To expand on this, before DRS, one of the complaints about F1 was that it was very difficult to pass, and races were often processions: they ended in pretty much the same order as they started (slight exaggeration).
To increase opportunities for passing, DRS was instituted. When a car is within one second of the car ahead at the DRS detection zone, its rear wing flap will open at the next straight, giving it a boost of speed of 15-20 kph until it brakes for the next corner. This is enough of an advantage to provide many more chances for overtaking, and has significantly enhanced competition in the series.
Thank you. Sorry to mislead anyone. I even did some reading to make sure I was right about F1 & moveable wings / flaps before I posted. Evidently somebody hasn’t kept their cite/site up to date. Oops on me.
In general, you’re right: Aerodynamic surfaces on F1 cars are required to be rigid and not flex. The DRS system is an exception to that rule, and tightly limited in how it can be used. But it does illustrate the point that much of the purpose of downforce in F1 is for cornering ability. On the straights they would much prefer to lose that drag and, when allowed to open up the DRS, they do get a big boost of straight-line speed.
Jim Hall designed a few of his Chaparral race cars with large, moving rear wings. The wing could turn vertical when needed, essentially an air brake to slow the car down. I think they were banned as a safety measure. If you were expecting to have that extra aero braking at the end of a straightaway, and any of the connections of linkages broke, there was nothing you could do.
The current DRS is very subtle in comparison. Only one section of the multi-element wing pivots up and down.
In addition to the braking you mention the Chaparral wings were faired on the straightaways and tilted to provide massive downforce going into a curve. If that didn’t happen, the car was totally going out the high side of the curve and badly so. Be that track edge a not-very-safe wall or hay bales or spectators. Tracks were not nearly as crash-safe then as they are now.
Couldn’t the same be said of any racecar brakes system?
As I read the posts in this thread, my brain keeps yelling upforce every time someone mentions downforce. 
(Because the car is intended to stick to the ceiling, eh?)
We’re all using a car-based coordinate system.