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Dear Physics legends/aerodynamicists of STW,
Sky TV are running an advert for the new F1 season that claims there is so much downforce that an F1 car could drive upside down. I call BS!
Really? How fast would the car have to be travelling to support it's weight?
Please show your working!
on a treadmill, or on an (upside down) road?
unless you know the overall co-efficient of lift for the aerofoils and their dimensions I doubt any calculation is anything other than an estimate
If the downforce is similar to previous times I've heard that quoted it's about 70mph. The cars only weigh about 500kg and they produce so much downforce they can corner at over 3G. To take a flat corner at 3G requires about double the vehicle's weight in downforce IIRC.
pretty sure that f1 cars generate more than 1G downforce, so yeah, they could
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[url= http://www.f1technical.net/forum/viewtopic.php?f=1&t=10705 ]GEEK-A-THON !!![/url]
Yes very possible, as above they weigh very little. The wings are kept small to reduce loads and reduce cornering speeds, with larger wings they'd generate even more downforce (or up force if driving on an inverted road). I saw some very interesting footage (could have been top gear) where unless the car was going pretty fast it was very unstable and didn't corner at all as car is light and grip is poor without the downforce,
I saw this ad earlier and thought similar. Ok, mathematically they could, but why don't they?
<I wouldn't want to be the guinea pig content>
But if we estimate a weight we could work out how much downforce is required and therefore if it's feasible?
Tom, there are too many assumptions and variables to accurately make a guess. If it is obviously feasible then maybe, but the assumptions may make the result marginal then there is little point.
A quick Google returns slightly more educated figures:
[url= http://www.f1technical.net/forum/viewtopic.php?f=1&t=10705 ]linky[/url]
I'd start watching again if they had some upside down sections on the track.
Gary Anderson film:
http://www.bbc.co.uk/sport/0/formula1/24772746
As for why don't they? How would you get it up there?
slowoldman - Member
Gary Anderson film:
http://www.bbc.co.uk/sport/0/formula1/24772746
As for why don't they? How would you get it up there?
Helical track.
Before I read any geek links, presumably any car that can generate more than 1G of downforce, irrespective of the car weight, can be driven upside down?
Now off to read geek links.
Yes, now I;ve thought more about it I'm completely wrong. 😉
Put the wings on upsidedown see if it flys 😆
I think its around 120mph, they produce I think 1600kg of downforce at 150mph, massively more than the cars weight, around 690kg
Pretty sure this has been quoted since the 90's and it's true. But the car would have to get up to speed the right way first, obviously, and then have a spiral track gradual enough.
A quick google throws up some similar race car data quoted here: http://www.ultimatecarpage.com/forum/showthread.php?t=41451
An f1 car weighs about 1500lbs so at 150mph we could pretty confidently assume that one would have twice it's weight in downforce at 150mph-ish.
Using the square law for lift then that would give about 70mph for the break even point, obviously you would need to exceed that by a safety margin. Of course you could also set up the wings in Monaco high downforce mode to get a better CL etc.
Wouldn't the oil I the engine just oil the plugs up or seep out the breathers or starve the oil pump
mav12 - Member
Wouldn't the oil I the engine just oil the plugs up or seep out the breathers or starve the oil pump
Not if you built the engine upside down
OOh, I know the answer to the this question.
Dry sump is the way forwards. Dirt bikes and planes use it.
If you bolt one F1 car upside down on the top of another, and drive at high speed into a mine...? 😉
OP. Have ever been on an aeroplane? Same principle, just turned upside down. You'd first have to get the car up to a speed where the downforce created exceeds the weight of the car, but then spiral round onto the ceiling and it would stay there.
The helical track mention made me think of The Man with the Golden Gun with the helical jump.
[url=
footage[/url]
KevJ, andy Craig - thanks for links and info.
Flying Ox - yes I have been on an aeroplane and have a working knowledge of aerodynamics. I am an airline pilot.
So why do you find it hard to believe? You obviously understand the physics of it all (I would hope...)
If you can create enough lift to get a 70-odd ton aircraft off the ground, why would it be BS to suggest that you can create enough lift to get a 500kg car off the ground. That's all you're doing. You're just stopping it going any higher with the ceiling it's driving on.
Some have tried..
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I'm sure they could with the right tweaks
Downforce gives you grip for corners, but makes you slower on the straights, so its a balance that is adjusted by circuit. Its also why you have thing like DRS so you can reduce the downforce generated by the wing
If they tweaked it for pure downforce and ignored top speed I'm sure its possible, just unnecessary for F1 use!
It would be easy to do in a wind tunnel, with a rotating floor...
Start the right way up. Get wind speed to 150mph. FLip that bad boy over!
DrP
if we're going to prove it works I want some fantastical bit of tarmac construction and a nutter to drive it not some namby pamby simulations, be gone with your simple [i]safe[/i] ideasStart the right way up. Get wind speed to 150mph. FLip that bad boy over!
Dry sump 😯
( that's the level of my input to this thread)
My sumps, my sumps, my greasy oily sumps.
I saw a documentary once where they drove a car upside down in a busy tunnel.
It was hosted by Tommy lee Jones and Will smith.
DrP
...
Here's a screen grab of it...
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DrP
[quote=D0NK muttered bleakly]if we're going to prove it works I want some fantastical bit of tarmac construction and a nutter to drive it not some namby pamby simulations, be gone with your simple safe ideas
this, 100 %
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This year they can barely drive the normal way up.
It would certainly make engine failures more interesting...
sure this one's been done before?
don't forget when doing the sums that the aero downforce upsidedown needs to have an additional 2x the weight of the car to get the same force into the road surface, if you want the same traction.
and when did kg become "force"?
I hope RB don't try it with their current car, breaking down upside down would surely injure someone's finger
and when did kg become "force"?
Since we've been all hanging out on the same planet 🙂
Since the 'mericans have always used lbf, and no one can be bothered to convert from lb to kg to N whem unless your NASA* g is always a constant.
*who use lbf but still define it on earth
Before I read any geek links, presumably any car that can generate more than 1G of downforce, irrespective of the car weight, can be driven upside down?
"1G of force"..? 🙂
And yet I reckon everyone understands exactly what was meant by it.
From recollection, F1 cars at top speed generate over 2000kg of force ( 😆 ) and currently weigh 691kg with an empty tank (or 100kg more with a full tank) so they'd very comfortably drive upside down. Or at least they would if they were designed to actually work upside down
helix, or loop the loop, very comfortably
drive, ie with enough upforce for the car to be able to put enough power down (err up) on the ceiling to be able to maintain enough velocity to generate that aero force? not convinced.
needs 2 * 691kg of aero "force" at 0 km/h just to stick to the ceiling with the same force as a car pulling out from the pits. we'll go with empty tank cos it'll need all the help it can get. don't recall if that mass is with or without driver?
anyone got a plot of a typical F1 car aero force vs velocity in Monaco spec ?
691kg of force is including the driver. And DF is related to (IIRC!) the square of the speed.
G is a ratio unit used in aeronautics, as well as the constant in physics.
You wouldn't do it for very long, before the fuel /oil pumps sucked air and you "fell off"..........(...........)
It's possible for a human to run around a complete loop, without falling off, so a high-speed vehicle with enormous amounts of downforce ought to be able to do it.
The sky advert doesn't show it doing a loop. It shows it driving upside down and claims this is reality. I call BS but I think we have to discount the engine failing upside down. Andy rocketeer has some interesting numbers. I have some aerodynamicists I know working on this! Will report back!
Yes it's possible, has been for decades. Even the new Maclaren Road car produces 6KN of downforce at full speed, and can go over speed humps.
If the engine works upside down and the car can get up to speed before gradually turning upside down then yes easy.
The sky advert doesn't show it doing a loop. It shows it driving upside down and claims this is reality.
Really?
Slowoldman - yes! A CGI sequence shows the car zipping along inverted and says 'these cars produce so much downforce they can even drive upside down'.
Even the new Maclaren Road car produces 6KN of downforce at full speed, and can go over speed humps
F1 car needs 14kN to stick to the ceiling just to overcome gravity and have the same downforce (upforce?) as a parked F1 car. Or the same downforce as a car the right way up where all the wings fell off at high speed (I'm assuming that all downforce comes from the wings here, for simplicity). We've certainly seen how little braking ability they have in that situation, but never how little drive traction they have when the rear wing falls off.
Downforce gives you grip for corners, but makes you slower on the straights, so its a balance that is adjusted by circuit. Its also why you have thing like DRS so you can reduce the downforce generated by the wing
Downforce has nothing to do with forward speed along a straight section of track. It's drag that makes you slower going forwards. The wings job is to create downforce but this cannot be done without creating drag at the same time, the trick is to get the balance of the two right. DRS reduces the drag (by effectively making the rear wing smaller but this also reduces the downforce - which it why they only use it on straight sections of the track.
Slowoldman - yes! A CGI sequence shows the car zipping along inverted and says 'these cars produce so much downforce they can even drive upside down'.
CGI you say? I wonder why they didn't show actual footage.
yes but the tarmac lorry would need to go upside down too, and they are much much slower.