Group C - ground effect?

[Fink Floyd]

This is something that's been puzzling me for a while. Are some of the Group C cars in GT (and in real life, obviously) ground effect cars? The ones I'm referring to in particular are the Jaguar XJR9 and the Nissan R92C, but others seem to have similar visual clues.

The reason I ask is mainly down to look. The Group C cars in GT seem to split into two groups in terms of the way they look; the early ones (Sauber C9, Nissan R89C, Jaguar XJR9) and the later ones (Peugeot 905, Nissan R92CP - the Mazda 787B and the Toyota 88C-V are more difficult to place). The early group is distinguished by their very 'unfinished' looking sawn-off rear bodywork and smaller rear wings (and in the case of the Jaguar and the R89C, those 'spats' on the rear wheels too) and a lack of any real diffuser on the back. Later cars have a big diffuser like the LMP cars today have (R92CP being a good example) which hides the rear suspension, which is visible on the early ones - the Mazda seems to be a bit of both, which is why it's hard to place. Does anyone know if I'm right about this? All the GT1 and LMP cars have flat bottoms and long tails, which may support the theory.

While I'm asking, also, does anyone else think that the R89C is a very odd looking car? When I first saw it, I thought it was just a short-tail version of the R92CP, but then I saw that there are more differences. It looks strange to my eyes, as if it has a very high centre of gravity - it looks very tall for its length. It's also really quiet, if you listen to the replays. Does it warrant its status as possibly the most difficult car in the game to get? The only car I can think of that's possibly as hard (or takes as much work, anyway) is the Sauber C9, which is significantly faster.

 

[G-T-4-Fan]

It's a mystery

Nah j/k but well. I think the R89C is one of the most BEAUTIFULL cars in the game. I dont care about center of gravity, dunno...I guess, if you say so. But it still is one beautifull car.

For the rest of the question I really dont know. The Toyota LMP car REALLY has the flat back end, it looks cool too but a bit odd. Though, because it looks odd it looks faster. Engineers dont mind weard looking cars, as long as it makes them faster:tup:

 

[Fink Floyd]

For the rest of the question I really dont know. The Toyota LMP car REALLY has the flat back end, it looks cool too but a bit odd. Though, because it looks odd it looks faster. Engineers dont mind weard looking cars, as long as it makes them faster:tup:

Is that the Minolta that you're referring to, or the GT-One? The GT-One has quite a long tail, I thought.

As for the R89C, I guess it's all down to personal taste.

 

[G-T-4-Fan]

Yep all taste:tup: And yeah I meant the GT-One

 

[Appie]

im more in the GT1 cars
always liked them but the LMP
are really fast too so:tup:

 

[Scaff]

This is something that's been puzzling me for a while. Are some of the Group C cars in GT (and in real life, obviously) ground effect cars?

Everything you need to know on this subject, in more detail and better explained than I ever could is covered here.

Mulsanne Corner

Easily one of the best websites on the net for Sportscar technical data, including a lot on aero.

Mulsanne Corner Downforce/lift data

This section should be what you are after, the old Ford GT40 is quite a scary one, 318lbs of lift at 220mph!!!!


Enjoy

Regards

Scaff

 

[Eric.]

This section should be what you are after, the old Ford GT40 is quite a scary one, 318lbs of lift at 220mph!!!!

Do you think GT4 models that?

 

[Scaff]

Do you think GT4 models that?

Not even close, apparently during the 24hrs the GT40 drivers could add upto half a turn of lock in either direction and it would have no effect on the cars direction, due to the amount of lift at the front.

Also when they did aero test simulations on a GT40 model for the development of the GT concept they found out that it would get airbourne at approx 225-230 mph. Hence the 'hidden' rear diffuser and extensive underbody aero work on the Ford GT, you just can't get away with that on a road car.

indeed


Scaff

 

[SavageEvil]

...

This section should be what you are after, the old Ford GT40 is quite a scary one, 318lbs of lift at 220mph!!!!

...

Now we know why the GT40 always goes off the road at the end of the Huanadiares in GT4, it becomes a plane at the end and just flies off the road, lol.

 

[Scaff]

Now we know why the GT40 always goes off the road at the end of the Huanadiares in GT4, it becomes a plane at the end and just flies off the road, lol.

Yep, better brake very early


LOL

Scaff

 

[X-Othermic]

Yep, better brake very early


LOL

Scaff

Christ, food for thought if you race in Le Mans...

 

[Alfaholic]

I can't say what, if any, racing cars in GT4 utilize ground effect apart from the Chapparal 2..um 2D... umm the one that looks like a refridgerator.

But I am pretty sure that many Group C cars used the technology because they are perfectly suited to it - being fully enclosed and all. Formula 1 cars had to grow long sidepods to take advantage of ground effect. Classic ground effect racing cars, i.e. those that gain the effect through venturis, would generally have two very long tunnels, open at the bottom, running almost the whole length of the car from just behind the front wheels to the very end of the car, one either side of the driver / drivetrain. They can be recognised by the skirts running between the front and rear wheels that are in constant contact with the ground. The Chapparal also has these skirts. Ground effect was effectively banned by specifying that the underside of the car had to be completely flat within the wheelbase. Do make up some of the losses, the diffusers that you see under the rear end of many race cars and indeed road cars were introduced.

The reason I believe many Group C cars used this technology is because I have seen plenty of footage of them spinning, then taking off while travelling backwards, which would make sense as the airflow direction and therefore action of the venturis would be reversed.

As for the wings, they also had to grow to compensate for the loss of downforce when ground effect was banned. But I can think of a few other reasons why the wings on LM and formula cars might be larger now than they used to be. Here they are, and please note that this is all speculation on my part.

1) Bigger wings compensate for a loss of downforce due to the lack of ground effect.
2) Wings have to be mounted lower, where they are less effective and generate less downforce. Therefore wing area is increased to compensate.
3) Engines are much more powerful now than they were in the '80s and can therefore cope with the extra drag of a larger wing.
4) Racing circuits have all come down with a nasty case of Chicane Measles - including Le Mans - this makes them slower and puts the emphasis more on cornering speed (big wing and downforce) rather than acceleration and speed in a straight line (small wing and low drag)
5) Aerodynamic technology has moved on and engineers have learned how to make more efficient, larger wings to generate more downforce for less drag.
Tyre technology has advanced allowing the tyres to carry more load at high speeds without suffering a failure. Therefore more downforce can be used.
6) Ummm sponsors pay by the square inch?

Anyway apart from the Chapparal I can't help with the original question but if any of the racers in GT4 have obvious side skirts, then they use ground effect technology. I suspect by the time the Jag XJR-9 and Sauber had past into the history books, so had the ground effect cars, if they hadn't already gone before that. It was banned from F1 in 1983 or 4 or so I think. Perhaps even earler. Piquet's championship winning Brabham of 1983 certainly didn't have long enough sidepods to be running ground effect, so it may have been banished by that time.

 

[kennythebomb]

That's very scary, Scaff - I never knew it was that bad on the GT40.

 

[Scaff]

That's very scary, Scaff - I never knew it was that bad on the GT40.

The realy scary thing is they didn't at the time, with hindsight its amazing no one was killed in one of them.

People seem to have a rose tinted view of the GT40, and while it did without a doubt achieve great things, every drivers tale of the car is of one that was a total nightmare to drive. By all accounts It was not an easy drive, and over the course of the 24hrs It must have been both physically and mentally draining. I have nothing but the deepest respect for every one of the GT40's drivers, but probably most for Jackie Ickx in 1969, the year the Porsche 908 was the favorite and Jackie Ickx and Hans Herrmann were swapping the lead three or four times a lap. I've got that race on video and its amazing stuff.

Regards

Scaff

 

[Jetboy.]

The realy scary thing is they didn't at the time, with hindsight its amazing no one was killed in one of them.

People seem to have a rose tinted view of the GT40, and while it did without a doubt achieve great things, every drivers tale of the car is of one that was a total nightmare to drive. By all accounts It was not an easy drive, and over the course of the 24hrs It must have been both physically and mentally draining. I have nothing but the deepest respect for every one of the GT40's drivers, but probably most for Jackie Ickx in 1969, the year the Porsche 908 was the favorite and Jackie Ickx and Hans Herrmann were swapping the lead three or four times a lap. I've got that race on video and its amazing stuff.

Regards

Scaff

Well, in actuality, two drivers were killed during testing: Walt Hansgen ignored team instructions to slow down in wet testing (1966) and later that year, Ken Miles died while testing the version that appears in the GT series, the "J Car".

The "nightmare to drive" thing is very correct; the cars were some of the most demanding automobiles ever driven. And yet, Dan Gurney afixed his seat belt at 195mph, steering with his knees!

If you choose not to spend seconds buckling your safety belt before getting underway, chances are that you can avoid a traffic jam of a typical LeMans start, which means it's probably safer. And you are more likely to have a good, undamaged car for the first lap.

And, actually, by the second lap, along the Mulsanne Straight, you can drive with your knees and buckle your belt--we've all done that. Once you get used to the speed, it's not all that different: 200 feels like 120 to most of us...

 

[kennythebomb]

Well, in actuality, two drivers were killed during testing: Walt Hansgen ignored team instructions to slow down in wet testing (1966) and later that year, Ken Miles died while testing the version that appears in the GT series, the "J Car".

The "nightmare to drive" thing is very correct; the cars were some of the most demanding automobiles ever driven. And yet, Dan Gurney afixed his seat belt at 195mph, steering with his knees!

Amazing info, Cory 👍

 

[DeLoreanBrown]

People seem to have a rose tinted view of the GT40, and while it did without a doubt achieve great things, every drivers tale of the car is of one that was a total nightmare to drive. By all accounts It was not an easy drive, and over the course of the 24hrs It must have been both physically and mentally draining.

http://stevemcqueen-justclickhere.com/

http://hypertextbook.com/facts/2005/LeMans.shtml

The reason I ask is mainly down to look. The Group C cars in GT seem to split into two groups in terms of the way they look; the early ones (Sauber C9, Nissan R89C, Jaguar XJR9) and the later ones (Peugeot 905, Nissan R92CP - the Mazda 787B and the Toyota 88C-V are more difficult to place

The 88C-V has pictures inc. those aeroparts&livery in here somewhere, but the other three are of a generic meld by PD, as Scaff said its aal here @ mulsanne corner;

http://www.mulsannescorner.com/

 

[Scaff]

And yet, Dan Gurney afixed his seat belt at 195mph, steering with his knees!

On an interesting note Jackie Ickx in the 1969 LeMans actually walked to his car, got in and did up each of his belts in turn, starting last by some margin. He did this as a protest at what he considered to be the unsafe nature of the running LeMans starts.

This threads started to turn into a mini LeMans trivia thread.


@DeLoreanBrown Steve McQueen's Le Mans is an excellent look at the race, almost more documentry than film. May I also recommend SpeedTribe a lot less conventional, but also excellent.

Regards

Scaff

 

[Fink Floyd]

On an interesting note Jackie Ickx in the 1969 LeMans actually walked to his car, got in and did up each of his belts in turn, starting last by some margin. He did this as a protest at what he considered to be the unsafe nature of the running LeMans starts.

True. If he'd known then how close the finish would be (Hans Hermann's Porsche 908 was only 300yds behind Ickx's winning GT40 at the finish) he might have considered running like the rest...

 

[Nift]

I remember years ago watching a documentary or something about aerodynamics and the development of the 917s, 936s all the way thru the 962s. A lot of focus was what happens under the car. I may have this on video - I can't remember.

The 917s early releases were a nightmare to drive. Some drivers admitted it was a frightening experience.

The lowest part of the car is somewhere near the center, where through physics, the air passing underneath actually pulls the car down, creating a vacuum of sorts.


Scaff - great links btw.