Ride adjusting suspension?

[Maxion]

One interesting note on this subject is the lotus of Raikkonen still sparking quite a bit at the later stages of the Melbourne GP. It is a bit strange for the car to still be that low even though nearly all the fuel is burned up. They're doing something funny with their suspension....

[langwadt]

One interesting note on this subject is the lotus of Raikkonen still sparking quite a bit at the later stages of the Melbourne GP. It is a bit strange for the car to still be that low even though nearly all the fuel is burned up. They're doing something funny with their suspension....

Thought about that last year, don't remember if it was lotus but, some of the cars were sparking alot under breaking in qualifying where they are runnning on fumes, wonder how they managed to run the same car with +100kg of fuel ..

[DaveW]

One interesting note on this subject is the lotus of Raikkonen still sparking quite a bit at the later stages of the Melbourne GP. It is a bit strange for the car to still be that low even though nearly all the fuel is burned up. They're doing something funny with their suspension....

There are quite legitimate ways of achieving that, although most compromise mechanical control (if they care about that). However, interlinking dampers front and rear does increase the scope for innovation.

[hollus]

A car on fumes in quali also has a higher speed at most places and hence higher downforce. It more or less compensates for the fuel weight in average, but probably not quite in the fastest bits of the track.

[ForMuLaOne]

A car on fumes in quali also has a higher speed at most places and hence higher downforce. It more or less compensates for the fuel weight in average, but probably not quite in the fastest bits of the track.

I hear this argument quite often but it is wrong to me. They choose their gearing for quali AND race in advance, so they do not become faster at the straights. Not "plus 150kg downforce" faster, what they have to, if they want to run lower than at the beginning of the race where this mass is in the fuel tank.

[hollus]

As said, it won't compensate for it at the end of the fastest straights, where as you say, gearing and otherwise drag will control the speed, but everywhere else... this is a back of the envelope calculation from 2010 when the talk was of ride height adjustment during pit stops:

I think that the two fastest teams have no ride height control in their cars out of the ordinary, all that they have is more donwforce than the opposition.

My first point, the 160Kg of fuel are irrelevant when the car is stationary. I don't want my car to be fast while stationary (ta-da!), but in the corners and when braking. It is the ride height in the corners and while braking that is important.
Now I'll put forward some very rough numbers. Feel free to change them, they are not particualrly accurate, but I hope they are in the right ballpark:
A typical empty tank lap is something like 4Km and lasts something like 80sec. Average speed is 4000/80=50m/s or 180Km/h.
A full fuel lap is 5 seconds slower, now 85 seconds, resulting in 47.06m/s and 169.4Km/h.
I'll assume that at 180Km/h downforce is 1200Kg. Admitedly, just a ballpark. This speed is representative of many corners and braking areas, but not all.
Downforce does, in a first approximation, vary with the square of the speed. 169.4Km/h is 0.941*180; squared, downforce at 169.4Km/h is now 88.6% of the downforce at 180Km/h or 1063Kg.
Hence, at the beginning of the race, the vertical force (minus car and driver) pushing the car down is 1063Kg downforce + 160Kg fuel= 1223Kg.
At the end of the race or in qualifying, it is 2Kg of fuel (to make it back to the pits) + 1200Kg of downforce = 1202Kg.
I only get 21Kg of difference, not so dramatic.
If the downforce is a tad higher, the numbers would cancel out and your car handles beautifully the same at all fuel loads. With less downforce, the difference gets larger and one has a ride height issue, which surely contributes to reducing downforce even more.

Of course all of that is a crude approximation, and some corners are taken with much more speed, ejem, downforce! than others. Also, the average corner is surely slower thanthe average lap. My point is that current F1 cars must be close to a situation where fuel weight is not an issue, and maybe that the fastest teams simply have one problem less to deal with. Then the effect of carryng fuel around is only extra inertia, and not variations in ride height.

[DaveW]

I like your calculations, Hollus, but I cannot imagine a race engineer ignoring the 4.5 mm increase in static rear ride height for the empty tank/qualifying condition if he were free to do something about it.

[Maxion]

hollus, your calculations can't really be correct since you're only talking about the weight. When it decreases the rear of the car rises up causing a change in angle of every aerodynamic surface on the car which changes it's properties. Not to mention the rake increases which makes the diffusor larger and prone to leakage.

[ringo]

Lotus have been trying this out since 2010. I remember when something went wrong with the front suspension for petrov at Bahrain.
They may well have a really good suspension system 3 year later.

Whatever it is there are doing stems from the fundamental dynamic differences between a heavily fueled car and a car on low fuel.
And it is not illegal. The suspension will still respond to the forces applied to it. All we need to do is figure out how they can do this.