Quote from ORION :

I guess he has more or less quit LFS a years ago, at least he has not been very active.

Ah, that explains how I was able to overtake him them .

I was racing against someone called ocr*Thunder last week. Is he in your team, or just pretending?

Quote from Rob76 :

Does anyone else have the problem where you have to uncheck 'compact windows' each time you visit or refresh LFSworld.net.

I'm using Firefox 1.0.6

It's a pain as I hate the compact windows setting, which minimises every LFS desktop window unless you move the mouse over it. A really annoying setting for it to default to every time.It also doesn't save my time zone after I set it, although that's less annoying.

I had the same problem the first week or two, but then it went away. I think Vic fixed it, but maybe you need to delete your cookies for it to work right

God yeah. I have to sit there looking at the minimap for a bit when I join a server.
You'd obviously normally have a pit crew member with a board showing which way to turn.
Maybe there should just be an on screen message saying 'Turn left' or 'Turn Right'.

Yeah, this is really essential. With S1, the car didnt change, so you only really needed one fast setup for each config. Now we have to constantly change things, and also remember how each setup performed for things like tyre wear etc.
I'd also like the setup format including a field for the best lap you've driven while using it.

Team Syncro Racing server will be on this config over the weekend and we'll probably try and have a little public practice racing on Sunday night. It would be nice to have actually had at least one race around the track before the lights go green on the ESL.

Yeah, I was going to say you need some serious practice. 1:27.xx is my PB so far, but need some more practice to get regular lap times that speed.

Yay, the woman from Delmonte she say yes. Looks like I shall be there, although I'll want to be on the road by about 8pm to get back in time for bed

'Cept ESL eh?

Yeah, I've not exactly found a wealth of places to practice online. Might try and persuade Law to stick the TSR server on it over the weekend so we can get some racing practice in.
Not sure about setups though, I'm just using the same setup from the FE green quali at the moment. Cant see why it would need to be much different.

Yeah, definitely all the fast FWD's are better with locked diffs once you adjust your turn in driving style and setup. Must admit I havent tried it on the RWD's yet. I've got a race coming up with LX4's so I might give it a shot to cure this horrible turn in oversteer.

If I get to go, we'll have to talk about transport Angel. I'm in the heathen barrowland of Trowbridge, so will be heading up in the same direction as you. I'll probably drive, although I would expect I'll be coming back early evening after the race.

Okay so I got told off for posting in the other thread, naughty boy eh?

It says in this thread that its up to teams whether on not they want to bring 3 drivers.

Mr. Dendy tells me in the other thread that it isnt.

Which is it, cos I would like to come, but I'm not going to bother if I cant drive.

Arhg, their forum is driving me nuts. I registered, patiently waited my 24 hours, activated my account and logged in. Hit reply, typed out a long post puuting the world to rights, hit continue and got a message saying you cant actually POST on a forum for 7 DAYS!! after registration.
Dumb as shite.

Quote from Gunn :

The problem is that obviously any fool with half a vocabulary can call himself a "writer".

Well yeah, but giving licenses to actual print publications is a good idea. However, print publications (with the obvious exception of PC Zone) do not review alpha code, and typically will only agree to review a game once its gone gold.
So obviously Scawen wasnt about to start sending out alpha software to print mags. I expect that when S2 'goes gold' so to speak, ie the first non-alpha/beta release comes out, then would be the time for the devs to start giving the media review licenses.

The pi - rootG confusion goes like this;

Our wrong equation was this:

Ha, yeah my fault.

Quote :

I read that equation as:
0.5 * Pi * (Stiffness/Mass) ^ 0.5

(that way seems clearer to me)

You're right, its much clearer. Still wrong though.
0.5*pi is not the same as 1/(2*pi) . Thats just algebra.


Yeah, in the version of the frequency equation that does include g, it would be cancelled out by the static deflection if you resolved out the full equation, because static deflection = (mass*g)/stiffness.

So the g/deflection part resolves back to stiffness/mass, which is where we were in the first place.

Just to try and clarify a couple of things, firstly understeer is when the slip angle of the front tyres is greater than the slip angle of the rear tyres. Doesnt matter if its above optimum or not.

Secondly, FF systems work in a number of different ways. You can either send 'effects' to the wheel via directX, ie preset patterns of forces like a wave or ramp, which the wheel software interprets and sends to the wheel, or you can send a 'constant force'.
The way that the effects feel on your wheel will be determined by your 'spring strength' and 'damper strength' in the control panel. For example, directX might send a bounce effect of given magnitude, then your wheel driver software will modify the actual spring force and damping amount based on your control panel settings.

However, if the software isnt sending 'effects' but rather is sending a constant force, then that force will not be modified by the spring and damper settings in the control panel, it just gets sent as is.

Thats why for sims that use constant force variation like GPL and LFS, the spring and damper setting in the control panel are not relevant. As I understand it, ISI sims and most arcade racers do use the spring and damper effects, so they will be effected by those settings.

Quote from Bob Smith :

OK so using these equations:

Deformation = Force / Stiffness
Frequency* = 0.5 / Deformation ^ 0.5

*which was simplified from: Frequency = 0.5 / (Force / Stiffness) ^ 0.5

Obviously increased force will increase deformation but will also reduce the frequency. How do I need to alter these equation so that downforce only affects deformation?

Dont do it Bob!! The deformation version of the frequency equation is a fudge based on the coincience that pi^2 = approx 9.8. I know thats the version I used in the excel analyser, but hey, we know better now.

Frequency = (1/(2*pi))*sqrt(spring rate/mass)

There is a version which includes static deflection, but you have to include g, or it doesnt work.

Frequency = (1/(2*pi))*sqrt(g/deflection)

Veeryy interesting.

It is very much a case of our assumptions and initial positions being different. Again, I cannot dispute what you are saying, in response to a given force they will oscillate with the same amplitude.

My little excel simulator effectively runs the 'drop' command from LFS, so the mass starts its motion at the springs natural length, ie x0 in your diagram. This means its actual vertical distance from its equilibrium point (ie. x1) varies depending on G or downforce, because the equilibrium point is lower. Hence is has a longer distance to accelerate before decelleration begins. Hence it shows a larger amplitude of oscillation.

But in operating conditions, when the initial displacement has already been taken up, this isnt relevant and so amplitude would remain the same.

Just goes to show that you were right to go with mathematical proof rather than iterative simulation

So I suppose the reason that aero cars tend to run with extremely high spring frequencies is not so much to control the amplitude of oscillations at a given speed, but rather to minimise the difference between displacements at different speeds. Ie. If your ride height changes by 100mm depnding on how fast you're going, it would play merry hell with your suspension geometry.

That makes perfect sense, but all you've shown is that the spring equilibrium point is lower, which I agree with completely. What you've just worked through sheds no light on the issue of amplitude at all.


Okay, I'll try explaining it a different way. Please try and answer this riddle.

In system A, gravity = 9.8 m/s. When the mass is moving downwards on the spring, it is being accelerated by both the spring force and gravity, after it passes spring natural length is is being decellerated by spring force and accelerated by gravity, so its decelleration = g - spring decelleration, and maximum amplitude is reached when this force decellerates the mass to zero velocity.

In system B gravity = 19.6 m/s. As it passes zero point, it will have a higher velocity, as the downward force on it is greater. Yet you claim that it will decellerate to rest in the same distance as in System A, despite it having a higher velocity, and being decellerated at a lower rate due to the increased downward G force.

So the question is, where does the mystery force come from?

Last edited by colcob, Tue 23 Aug 2005, 18:41.

There is no such thing as equivalent mass. Force and mass are two different things so you cant just take the forces and divide by 9.8 to give you a mass. The inertia of the car (ie. its resistance to being accelerated) remains the samee regardless of downforce.

The mass remains unchanged, the suspension frequency remains unchanged. All that changes with downforce is the amplitude of the oscillation.

Quote from avih :

2. Any amount of gravity does NOT affect neither frequency NOR amplitude of the motion.

Can you explain in detail how you come to this conclusion please?

Its clear to me that the overall gravity effects amplitude in a vertically oriented spring system. Downward force effects downward acceleration which results in higher velocity passing through the zero point, which results in longer overall extension to reverse the direction, which results in higher upward spring forces, which results in higher upward velocity passing the zero point, which results in higher maxima of the upward phase.

Ie. higher gravity results in higher amplitude.

I've added a G slider to the oscillation graph in the analyser and it clearly shows that increased G increases amplitude.
Now you can reasonably hold the opinion that an iterative graph generation is not the same thing as a mathematical proof, but nonetheless, its fairly clear.

Last edited by colcob, Tue 23 Aug 2005, 15:49.

Quote from ebola :

In the UK we use hazards to thank people for letting us in etc

Not those of us that have ever read the highway code.
Its illegal to activate your hazards while moving, for the obvious reason that someone on one side of you will think you are indicating in that direction, and could easily pull out of a side road in front of you.

Quote from Gunn :

That was completey differentThat was different. mdmx is talking about restricting the throttle range until the button is pushed.

Hey. My momo pedals already do that.

Exactamundo.

I plugged the extra downforce into the drop simulation graph in the old excel setup analyser, and took all the damping off to see undamped harmonic motion, and you basically get the exact same frequency with higher amplitude.