downforce

[darksag3x]

do modern LMP prototypes (like the bentley speed 8) generate more downforce than formula one cars do? how much downforce do lesser formula three cars make?

[Guest]

I am going to guess the modern LMP car do generate more downforce, but I since F1 car are some 300+ kilos lighter than LMP cars they also don't need as much downforce.

[Tom]

I know for a fact that sportscars, without as many rules and regs on the subject, have far more than f1 cars. Anyway is weight not a factor of downforce, afterall the more weight the more downward forces acting on the car.

[Guest]

Downforce is typically considered to be a function of aero for the purposes of any discussion (weight is prejudicial to fast cornering..............inertia).

I have read that sports cars in the past have had really good drag/lift ratios. Due to closed wheels and a large underbody area. Imagine a pressure drop of 1/2 pound over 2000sq inches against 1000sq inches?

[RH1300S]

Downforce is typically considered to be a function of aero for the purposes of any discussion (weight is prejudicial to fast cornering..............inertia).

I have read that sports cars in the past have had really good drag/lift ratios. Due to closed wheels and a large underbody area. Imagine a pressure drop of 1/2 pound over 2000sq inches against 1000sq inches?

That was me - not logged on!

Should have said:

I have read that sports cars in the past have had really good drag/lift ratios. Due to closed wheels and a large underbody area. Imagine a pressure drop of 1/2 PSI over 2000sq inches against 1000sq inches?

[RacingManiac]

Would the consideration of weight be taken into account though when related to actual cornering force? If 4 tires can generate 6000lb of lateral load, for a 1320lb car that would be equivelent of 4.5G, while for a 2000lb car it'll only be 3G. Since downforce are there for maxmize grip of the car, a lighter car wouldn't need as much downforce to generate a given cornering G?

[RH1300S]

Would the consideration of weight be taken into account though when related to actual cornering force? If 4 tires can generate 6000lb of lateral load, for a 1320lb car that would be equivelent of 4.5G, while for a 2000lb car it'll only be 3G. Since downforce are there for maxmize grip of the car, a lighter car wouldn't need as much downforce to generate a given cornering G?

Yes, I am sure you are right. But there was a time when I am fairly sure that sports prototypes were generating more raw downforce for less drag than F1 cars of the day.

[zac510]

Yes, I am sure you are right. But there was a time when I am fairly sure that sports prototypes were generating more raw downforce for less drag than F1 cars of the day.

Yeah certainly, some of the Group C cars of the late 80s and early 90s are reputed to have been doing so.

Of course both modern F1 and sportscars are heavily restricted by regulation

http://www.mulsannescorner.com/data.html

[West]

I think modern prototypes create more downforce due to the fact that they aren't restricted by open-wheel aerodynamics. They may create more downforce, but they suffer a weight penalty (for the LMP900 class, that's 300 kg). So although they may have more downforce, they suffer much bigger acceleration penalties.

Incidentally, prototypes suffer less drag.

[ranger]

if prototypes suffer less drag then a true race car gets more drag ...

[RH1300S]

if prototypes suffer less drag then a true race car gets more drag ...

By "true" you mean open wheeler? (I would argue that sports prototypes are pure race cars BTW )

An open wheel car is very draggy because of it's wheels sticking out in the air AND rotating - messy, messy, messy! Don't forget that open wheel cars with lots of power can get away with trading drag for downforce when chasing lap time (which is the only thing that matters - maybe I should elapsed race time).

Less drag for an amount of downforce doesn't make sports prototypes "better" - just different..........

[Tom]

But I bet open wheelers are a heeluvalot lighter and proborbably easier to work on suspension and steering wise than any other kinds.
Also open wheelers are F1, its been that way since the beggining of time,
Neubauer and Porsche were using open wheels in the fifties, and it had already been used forty years before them.

[RacingManiac]

I think closed wheel car allows way more creative freedom as to how to approach the same problem of making a fast car. F1 nowadays seems to optimized that you try something really different and you get punished for it(Williams' Tusk for example).

Look at the history of sportscar racing and there have always been cars that's different and did quite well for itself. For your "run of the mill" GT40 there are the Chaperrals(sp?). For your regular 956/962 there are the Lancias. And then there are the fasinating "what ifs" like the Allard J2X(for the 3.5 liter formula in early 90's Group C) and the more modern Toyota GT-One and Bentley Speed 8s....and in terms of sophistication and servicability the modern endurance cars are quite amazing, I mean no F1 car can change their entire transaxle/rear suspension in under 5 mins(a la Audi R8...). They are afterall designed to run 24 hours and be fixed of small problem in short amount of time....

and then this is without mentioning some of the lower echelon of sportscar racing like the C-Spec/D-Spec Racers in US's SCCA club racing level. Much like UK's hill climb scene for road courses and with cars ranging from someone's garage creation to the more exotic Stohr's to Formula Atlantic based, converted to closed wheel car....

[rob]

do modern LMP prototypes (like the bentley speed generate more downforce than formula one cars do? how much downforce do lesser formula three cars make?

Yeas LMP cars do generate more downforce than formula 1 of nowdays.
But main difference is in aerodynamic efficienty -lift/to drag ratios.
Best F1 cars can get close to L/D=3,5 and LMP prototypes have L/D nearly 5.

F1 cars in early 90´s generated more downforce than F1 of nowdays Something around 1100kg@200km/h with L/D=4,0.

[dumrick]

And then there are the fasinating "what ifs" like the Allard J2X(for the 3.5 liter formula in early 90's Group C)

And don't forget the unraced Peugeot 905 Evo2.


I actually believe that, technically, prototypes are a lot more interesting than F1. This is because there is a higher degree of freedom allowed. Just search through the cars at mulsannescorner.com and see so many different aero and mechanical solutions. F1 is heavily regulated nowadays and open-wheelers are naturally a lot more constrained in terms of possible solutions.