Marc Gene escapes a big one at Le Mans

[FourWheelDrift]

The Peugeot getting airborne and being captured on the circuit CCTV.

Video clip on here.

http://www.lemans.org/24heuresdumans/actu/2008-06-...

[Chassis 33]

Lets hope we don't get a spate of these like the Mercedes in '99.

Regards
Iain

[MonkeyHanger]

Didn't something similar happen a few weeks ago in the ALMS?

The problem with the cars is, once they get sideways the airflow lifts them up...and the results are obvious.

[anonymous-user]

The problem with these cars is they are so damn fast in the corners and rely on a lot of aero, once the aero has gone they are in serious trouble. They remind me of the ground effect F1 cars, on a knife edge of grip that is highly aero dependant compared to the mechanical grip potential.

[MonkeyHanger]

Just to correct my earlier post it wasn't the ALMS but the Le Mans Series @ Monza

http://uk.youtube.com/watch?v=Ftp2C9Y2Oj8

[Scuffers]

as said, not the same as the Merc issue... that was because of flat bottom cars (A stupid idea for these cars).

[freedman]

Scuffers said:

as said, not the same as the Merc issue... that was because of flat bottom cars (A stupid idea for these cars).

And the current cars dont have flat bottoms?

[Eric Mc]

Sports cars by their very shape and design tend to present a flat surface to the airflow if their fronts or sides lift for any reason. At 150mph, once that happens they are very likely to fly. It's a phenomenon that has been present since the 1950s when enclosed wheels and wide bodywork became the norm for Le Mans type cars.

Edited by Eric Mc on Tuesday 3rd June 08:34

[MrKipling43]

freedman said:

Scuffers said:

as said, not the same as the Merc issue... that was because of flat bottom cars (A stupid idea for these cars).

And the current cars don't have flat bottoms?

IIRC the problem with the Mercs was that they had a tunnel running the length of the bottom of the car and, because of the way that affected downforce, the closer the car was to the ground the more downforce you got. However, if the car bottomed out the airflow would be cut and you'd lose all aerodynamic grip - which could cause the car to lift off.

[Scuffers]

MrKipling43 said:

freedman said:

Scuffers said:

as said, not the same as the Merc issue... that was because of flat bottom cars (A stupid idea for these cars).

And the current cars don't have flat bottoms?

IIRC the problem with the Mercs was that they had a tunnel running the length of the bottom of the car and, because of the way that affected downforce, the closer the car was to the ground the more downforce you got. However, if the car bottomed out the airflow would be cut and you'd lose all aerodynamic grip - which could cause the car to lift off.

no so....

the regs are the time mandated FLAT floors, as in no tunnels...

ACO had some time before commisioned a report of the effects of banning tunnels etc, and it concluded it would be dangerous, but they went ahead anyway.

the problem with flat floor cars is that they become massively pitch sensitive, and (as seen) one bump in the wrong place and it's all over, with a fully tunneled car (like the last the group C stuff) this just would not happen...

[DavidCane]

That's the scariest crash I've seen for a bloody long time (bar Kubica's). This is reminding me of easily the IRL cars get airborne, it's really worrying stuff.

On the other hand, the way that Peugeot stood up to the hit is very very impressive.

[Chassis 33]

There was an SAE paper written on the Merc accidents (it's at home, so I can't quote verbatim, however...)from what I remember the car was very poor in turbulent air. In a laminar flow it had huge amounts front end downforce, however in turbulent air the aero balance moved much further back on the car and as the car rose of the crest of the road the front end stalled then flicked up. A similar thing happened earlier in the '99 season in one of the American races, Sebring or Daytona IIRC.

If anyone is really that interested I could scan and email it this weekend.

Regards
Iain

[Ahonen]

Chassis 33 said:

There was an SAE paper written on the Merc accidents (it's at home, so I can't quote verbatim, however...)from what I remember the car was very poor in turbulent air. In a laminar flow it had huge amounts front end downforce, however in turbulent air the aero balance moved much further back on the car and as the car rose of the crest of the road the front end stalled then flicked up. A similar thing happened earlier in the '99 season in one of the American races, Sebring or Daytona IIRC.

If anyone is really that interested I could scan and email it this weekend.

Regards
Iain

Yep. They also ran relatively soft rear springs on the Merc to flatten out the wing at speed, which accentuated the problem and led to negative rake at high speed and a huge change in front throat height. The very long overhangs from that era made the cars incredibly pitch-sensitive, which is why they have such short overhangs now.

LMP1s are big cars with relatively flat floors and if something goes wrong they can turn into flying machines if the wrong set of circumstances combine (as have done a couple of times recently), but the cars are most certainly not unsafe. The amount of aero they have is far less than the old LMP900s, which had huge overhangs and tiny ground clearance.

No doubt some busybody at the FIA is rubbing his hands with glee at the prospect of slowing them down, though...

[freedman]

Scuffers said:

MrKipling43 said:

freedman said:

Scuffers said:

as said, not the same as the Merc issue... that was because of flat bottom cars (A stupid idea for these cars).

And the current cars don't have flat bottoms?

IIRC the problem with the Mercs was that they had a tunnel running the length of the bottom of the car and, because of the way that affected downforce, the closer the car was to the ground the more downforce you got. However, if the car bottomed out the airflow would be cut and you'd lose all aerodynamic grip - which could cause the car to lift off.

no so....

the regs are the time mandated FLAT floors, as in no tunnels...

ACO had some time before commisioned a report of the effects of banning tunnels etc, and it concluded it would be dangerous, but they went ahead anyway.

the problem with flat floor cars is that they become massively pitch sensitive, and (as seen) one bump in the wrong place and it's all over, with a fully tunneled car (like the last the group C stuff) this just would not happen...

The Peugeot has aflat floor, no?

[anonymous-user]

The Can Am cars went through a stage of taking off on the high speed bumpy tracks, they used to induct the drivers into the Can Am flying club after an incident, they had some really big shunts at the time. They fixed this by smoothing out the circuits so they didn't have any big crests on the high speed sections, plus they learned more about the underfloor aerodynamics. The current issues aren't the same, they seem stable when traveling in the right direction, they go very unstable once you have them at a high degree of yaw.

NASCAR fixed their flying problems with pop up flaps in the roof, for when the car got a high degree of yaw or were backwards.

[Chassis 33]

johnfelstead said:

NASCAR fixed their flying problems with pop up flaps in the roof, for when the car got a high degree of yaw or were backwards.

Then fixed it properly with the introduction of the "Car of Tomorrow" platform.

Regards
Iain

[LaSarthe+Back]

Does anyone know if he's OK?

[Chassis 33]

Seems to be http://www.autosport.com/news/report.php/id/67948 read somewhere else that there was a suspicion of a broken toe, but probably just heavy bruising.

Regards
Iain

[LaSarthe+Back]

Chassis 33 said:

Seems to be http://www.autosport.com/news/report.php/id/67948 read somewhere else that there was a suspicion of a broken toe, but probably just heavy bruising.

Regards
Iain

"recovering and being ready to race"

Top lad!