15 replies to this topic

[slipstream]

Does anyone know or have a good guess on how much Downforce a modern F-1 car has ? I have heard that a Champ car with it's Road racing setup has about 5,000 lb of downforce at 200 mph,Does a F-1 car produce more Downforce than a Champ car ?

[desmo]

In high-downforce trim an F1 car produces close to 3000lbs. of downforce at 150mph with a lift/drag ratio of less than 3:1.

In medium-downforce trim it is 2,500-2,800lbs. at 150mph at a better lift drag ratio of around 3:1.

In low-downforce trim the downforce figures are obviously less, but the lift/drag ratio improves to something like 3.3:1.

It is possible to dial in virtually any amount of downforce within reason. The trick is to get the most downforce from a given amount of drag.

[Ali_G]

I know that at 200 mph an F1 car's normal reacton is multiplied 3 times. Therefore running max downforce it would appear to be 3 times its original weight.

Niall

[desmo]

You can calculate downforce at any speed from the figures I posted above. Just figure downforce as a function of V squared. This is, I'm sure, an approximation as the airflow in real-world situations doesn't behave in an entirely predictable way.

[Yelnats]

We must factor in the additional weight of a CART car to derive the effectiveness of the downforce generated and a CART car requires much more downforce to generate a given cornering force. Since a CART car weighs about 25% more than a F1 car it requires about 25% more downforce to achieve an equivalent increase in cornering force and experiences greater drag due to larger wings.

This is part of the reason that I believe an F1 car has a similar top speed potential as a CART car. Considering the smaller frontal area (narrower track and tires) and smaller wings for a given down-force to weight ratio, the F1 cars 12% to 15% HP disadvantage would soon be balanced out when set up to run a theoretical superspeedway lap.

[moog101]

It is entirely possible to drive a current F1 car along the ceiling at about 60 mph.

Now that would be a media stunt....

[desmo]

That isn't going to work at 60mph, I'm afraid. Even with a Monaco aero package.

[Powersteer]

Generally i is thought that a car with slick tyres can do 1 G forces or more. Add double weight downwards with the same horizontal weight you get double the G so It is learned that the F1 cars today are reaching 4G's plus.Very innacurate but you can get the general idea of how much downforce it produces, ciao

[Ali_G]

I believe that its something like 110 mph with Monaco setup to drive upside down. That would be spectacular but very dangerous.

Yelnats: I also agree with you over a F1 car having a higher top speed than a CART car.

1. An F1 car is slim. CART car is not.

2. F1 car uses multiple elements in wing for efficent downforce. CART uses one giant wing. Not efficient.

3. An F1 car has a higher power to weight ratio than a CART car. Therefore an F1 car can lenghten it gear ratios much further as it won't reach Terminal Velocity as easy as it has more power for a certain acceleration due to its greater power to weight ratio.

Niall

[BADGER]

I think the downforce levels of indy cars and F1 cars are very similar. The current diffuser area for an indy car is so small (22 inches wide) that it probably produces about the same downforce as a f1 with a larger diffuser but with a flat under body.

Additionally, Ali please stop arguing that since a F1 car has a higher power to weight ratio, it can be geared for a higher top speed than an indycar. Top speed is determined by horsepower and drag, and weight is nowhere in the equation. The simplified equations from the book "Race Car Engineering and Mechanic" states:

drag force = (0.0025)Cd(Frontal Area)(Velocity) squared
Cd = coefficient of friction

Horsepower = (.0027) (drag force) (velocity)

As the equations show, if you double your top speed, your drag force goes up four times and your horspower requirements go up 8 times.

[moog101]

My figure for speed was from CAR magazine - I have never bothered (nor had the information) to check it's accuracy, though as it is obvious they generate easily enough downforce then I cannot understand why no-one had tried it. You could even crash and you'd be OK with the roll over regulations.

[colejk]

I'm not exactly sure of the TV program, but i believe it was on the Discovery channel a few years ago. A modern day race car (and they didn't specify F1 or CART) could drive upside down at 200 mph. They showed a comp. simulation of a race car driving down a circular shaped tunnel. Actually very cool. Due to more restrictive aero regs these days I wonder if that would still hold true.

[MacFan]

colejk, all that is required for the theoretical upside-down F1 car stunt is for the down(up?)force created to be in excess of the weight of the car - the same equation which applies to aircraft. From desmo's figures above, an F1 car can produce over 3000lbs (1364kg) of downforce, I believe the weight of car and driver is around 600kg, therefore the downforce is sufficient for the car to cling to the ceiling. Don't try it at home though...

[MacFan]

Originally posted by Ali_G
2. F1 car uses multiple elements in wing for efficent downforce. CART uses one giant wing. Not efficient.

CART's aerodynamic package is potentially more efficient than F1's, at least without the Hansford wing, as CART still utilises ground-effect tunnels, which are a more efficient means of generating downforce than the wings or diffusers of an F1 car.

[westendorf]

The weight of a car is not all that important to the top speed. It may take longer to reach max velocity however. Ciao, GFW

[PDA]

Ali - we have had this argument about weight and top speed elsewhere. at those speeds, weight is insignificant. Drag is all important. In 1937, Mercedes and Auto Union ran in the Avus GP with enclosed body cars weighing in excess of 800 kilos. They reached in excess of 250 mph on the long straights becasue they had very low drag bodies.

gascoyne of Jordan states in an article in F1 racing that in Monaco trim, and at Monaco top speeds, total weight on the tyres is 2.5 times the static weight. cD in that trim is in excess of 1.0. In Hockenheim trim, cD is in the region of 0.7.