18 replies to this topic

[Jhope]

2001 Penske-Reynard-Honda 2KI Indy Car

Road track configuration: Downforce:
3328 lbs. @ 165 mph, with 1119 lbs. of drag
4888 lbs. @ 200 mph, with 1644 lbs. of drag

Lift-to-drag ratio: 2.97:1



Short Oval (1 mile) Package
Before Tunnel Blockers (1992 - mile oval)
(5-element cascade rear wing, rock-hard tires)
Wings 3,000 Underwing 2,200 Total5,200

Before Tunnel Blockers, but smaller tunnels
than in 1992 (1995 - mile oval, tires better but still not as good as today)
Wings 1,800 Underbody 2,200 Total4,000


1998 Formula One Car

High downforce configuration: Downforce:
3000 lbs. @ 165 mph

Low downforce configuration: Downforce:
2500 lbs. @ 200 mph, with 909 lbs. of drag

Lift-to-drag ratio: 2.75:1


1981 skirted ground-effect F1 car Downforce:

561 lbs. @ 62 mph
2244 lbs. @ 124 mph
5060 lbs. @ 186 mph


Just wanted to ask if these numbers make sense. For some reason, even with the limited ground effects CART are allowed to have, I always thought F1 cars produced more downforce. I know also that it's a weight issue. 600 vs 900KG's. But still, thes enumbers look a little weird.

Source

Anyone else think that F1 should put more reliance on limited undercar downforce and wing configurations instead of the diffuser and huge wings we have today?

[DOHC]

Very interesting figures. They look like very high downforces. Also, lift/drag ratios are rather lower than I would have guessed, near or below 3 rather than 4.

Future changes? Considerably smaller wings, let's say max 0.2 sq m wing area at both front and rear, at most two elements front, two on the rear.

But lower the front wing -- I think that raising the front wing was a mistake. Behind another car it runs in dirty air and becomes less effective. Braking is compromised, overtaking is difficult.

Then flat bottom + diffuser, no venturis. Goal: reduce aero grip and rely more on mechanical. Allow a bit more ground effect than today (esp front wing), both for safety and so that downforce is less compromised by running close to another car.

Further: slicks, wider track cars. I think this would take off almost half of today's F1 downforce, and improve mechanical grip. A completely different balance.

[Jhope]

I kinda take my solution from today's and yesteryears Prototype cars.

[Ross Stonefeld]

hmmm, there should be a lot more downforce in an F1 car. What is an Indycar but an overpowered F3 really? Its an 'off the shelf' chassis vs a constantly developed custom built one of a kind car. Im afraid I dont trust those figures

[Schummy]

I don't think producing "brute force" pounds of downforce is so difficult for a competent race car designer (F1 or not), rather I think the mastery is things as the lift-drag ratio and the finesse, those little details that amount to about 0.5-1% in lap time.

Having in consideration CART regulations and the evergoing restrictions in F1 regs, I'd be surprised if CART cars don't have more gross downforce.

[Julius]

Originally posted by Ross Stonefeld
hmmm, there should be a lot more downforce in an F1 car. What is an Indycar but an overpowered F3 really? Its an 'off the shelf' chassis vs a constantly developed custom built one of a kind car. Im afraid I dont trust those figures

So what? Do you really think that much downforce (or the current horespowers, even) are difficult to achieve at a budget?

Here's what could easily be: Take a two-year old CART car to Monza. Give it some better Brakes. Let it run any downforce package the driver wants. Let is have as much boost as it can handle for a complete road race. Take some of the ballast out. Give it some wider tires. Then watch mostly 20-year-old technology run laps around Monza while breaking all the records. Repeat on any road course of your choosing.

Seriously, the restrictions placed on most all race cars are artificial restricitions designed to slow the hell out of them - to keep them from overwhelming the tracks - F1 cars especially. Grooved tires, narrow chassis, limited wings, no turbos, etc. limit the hell out of what an F1 car could be. However, do people want F1 cars to be all they could be, would they want to witness that kind of speed-induced carnage?

[Ross Stonefeld]

Remove the restrictions from F3, F3000, LMP900 and F1 cars while you're at it, and they'll all go faster too, whats your point?

[Aubwi]

I find those numbers fairly believable. CART has venturi tunnels, and a larger overall size so there's just more bodywork to generate downforce.

But I think the lift/drag ratio is much more important than overall downforce, and F1 has probably closed the gap in that respect since 1998.

Champcars are much heavier, so they need more downforce to achieve the same cornering g's. Also, champcars aren't as powerful as they used to be, so they probably aren't running as much wing. So I don't think those figures neccesarily suggest that a champcar can corner any better than an F1 car.

[EvilPhil]

Well we will find out when the go to canada later this year wont we.

[DOHC]

I have checked some of the numbers, doing calculations.

Some observations:

1) For the 2001 Penske-Reynard-Honda downforce and drag are given at two different speeds. Theory says that drag increases as v^2. When you check the quoted figures, you see that both downforce and drag exactly follow this rule. This is a clear indication that the data are theoretical and not based on measurement. Same thing with the skirted F1 car, theoretical data.

2) Drag figures are clearly total drag for car + wings, which means that quoted "lift/drag" numbers aren't comparable to lift/drag numbers for wing profiles. This explains why lift/drag is "low". But considering that it's total drag, I find the lift/drag figures very high. That is then an indication that a large portion of downforce is ground effect, at least for the 2001 Penske.

3) The total drag at 200 mph can be used to work out engine power consumption for overcoming the drag. For the 2001 Penske we find that 889 hp is used to overcome drag @200 mph. For the 1998 F1 car in low downforce configuration, the corresponding figure is 492 hp.

Some comments: I'm not sure what the available traction power is for the 2001 Honda, but unless it's significantly higher than 1000 hp, the car won't go any faster than 200 mph. (Note that transmission losses, generation of electricity and hydraulic power, roll resistance etc is not accounted for in the total drag figure.) But qualifying at Indy requires average speeds in excess of 220 mph, and top speeds nearing 245 mph. Of course, the car can be run in a lower drag configuartion than what is mentioned here.

I would put some question marks here and there concerning these figures. While not impossible, some are theoretical, and some come awfully close to using up all available engine power.

[Ross Stonefeld]

They were running over 200mph at Road America down the straights in road course trim with a road course version of the handford wing. I think a few guys hit 208 going into the brake zone at the end of the fastest straight.

[Aubwi]

I heard when they run at Montreal they'll run on different layout of the circuit. Don't know what theyre going to change.

But Mexico City should be interesting. Might be possible to compare that with 1992 F1 cars.

[Ross Stonefeld]

Montreal will be exactly the same.

Mexico is no longer the same layout it was for F1. The last corner isnt the parabolica anymore, and whats left of parabolica is flat instead of banked

[Jhope]

Originally posted by Aubwi
I heard when they run at Montreal they'll run on different layout of the circuit. Don't know what theyre going to change.

But Mexico City should be interesting. Might be possible to compare that with 1992 F1 cars.

Nope. the circuit will be exactly the same as it was this past June for the Canadian GP.

[ehagar]

Originally posted by DOHC

3) The total drag at 200 mph can be used to work out engine power consumption for overcoming the drag. For the 2001 Penske we find that 889 hp is used to overcome drag @200 mph. For the 1998 F1 car in low downforce configuration, the corresponding figure is 492 hp.

Get the same thing... We are probably comparing two different extremes of set ups. The question is not which car can produce the most downforce, that is academic. The question is, which car can have the optimum result per circuit. Garbage in, Garbage out.

[Yelnats]

As mentioned by several posters, total downforce is a pretty meanig less way to rate the efficiency of an areodynamic design. If that were the only consideration then dirt track racers with their huge dining room table sized wings would win hands down. The lift/drag ratio is the critical factor and a pretty finely tuned figure it is to. I would estimate that the differences between the L/D ratio between the best and worst F1 car would be less than 5% and a difference of 1% would make the difference between a pole position and a second row grid qualifying spot. Its amazing that with all the restrictions put on F1 cars recently, they still continue to improve areodynamicaly.

The figures posted seem resonable an would give a F1 car a huge cornering advantage over a CART car. We must remember that because of the much lower weight, an F1 car would have a greater than 25% advantage in cornering Gs assuming the same down force at a given speed.

[Arneal]

Originally posted by Ross Stonefeld
hmmm, there should be a lot more downforce in an F1 car. What is an Indycar but an overpowered F3 really? Its an 'off the shelf' chassis vs a constantly developed custom built one of a kind car. Im afraid I dont trust those figures

That is all irrelavent.

It comes down to whether budgets or regulations are more important for making a car fast. We are all used to watching series where all the cars are subject to the same regulations and, thus, a teams budget is very important to making the cars fast. The more you spend the faster you go. But when you start comparing cars from different series than you have to take regulations into account and regulations trump budgets. That was the point Julius was trying to make. Regulations have a bigger effect on a cars downforce than budgets do. CART allows underbody tunnels thus they have more downforce. It has nothing to do with budgets.

[MONTOYASPEED]

Originally posted by Ross Stonefeld
Mexico is no longer the same layout it was for F1. The last corner isnt the parabolica anymore, and whats left of parabolica is flat instead of banked

The Parabolica is in Monza.

[Izzy]

The last corner at Mexico is also called the Parabolica.

So wipe that smile off your face.