Short wheelbase Vs Long wheelbase 2011

[Pup]

Is it because of the fixed weight ratio? Would a longer wheelbase exacerbate or ameliorate a weight balance issue, assuming it's not ideal?

[ringo]

I don't know, but i would guess there is less weight shift in the longer wheel base, if we do the maths.
I would guess that could be ideal depending on what the team wants from their car and tyres.
It may be easier to set up a car with less weight shift i guess.

[wesley123]

Well, I think a longer wheelbase is better. It allows for better aerodynamics at the rear.

An possible weight and balance issue is kind of neglected by the fixed weight distribution. The only thing making sense is a possible CofG reduction. Apart from that, a longer wheelbase car will suffer less from full/empty tank difference is my quick guess.

[Jersey Tom]

Longitudinal load transfer can be a good thing, y'know.

[Caito]

Longitudinal load transfer can be a good thing, y'know.

JT, would you mind explaining or giving an example?

Thanks!


bye bye

[DaveW]

All been said, really.

From a mechanical perspective, long wheelbase = stability, short wheelbase = agility.

F1 wheelbases have tended to increase since 2006, probably because moving the rear wheels back relative to the chassis is a quick way of moving c.g. & c.p. forward without major aero mods. Probably made it easier to accommodate a larger fuel cell last year, KERS & pull-rod rear suspension this year. Shark fins have probably helped to recover lost weathercock stability.

[mep]

How many mm are we even talking about here?
You chatted 2 pages but nobody brought some figures.
That’s not how it should go. First check how big the difference is then think about what effects it might cause.

[raymondu999]

I was thinking on all this, and a question popped up. Does the fuel tank position have to be at the CofG location? I'm thinking full tank vs low-fuel glory run, the balance and weight distribution would change more on a SWB car than an LWB car, if the fuel tank isn't in roughly located at the CofG.

[JohnsonsEvilTwin]

+1 mep

If anyone has figures and formulae, it will be greatly appreciated.

[DaveW]

Some (scaled) information here: viewtopic.php?p=226026#p226026

[747heavy]

Longitudinal load transfer can be a good thing, y'know.

JT, would you mind explaining or giving an example?

Thanks!


bye bye

How about start line performance / power down?
think about drag racing as an extreme example


as for the value we are talking about. If we take Richards photo comparsion, it looks like ~ 1/2 rim diameter so perhaps 160-170 mm is in the ballpark.

[ringo]

All been said, really.

From a mechanical perspective, long wheelbase = stability, short wheelbase = agility.

F1 wheelbases have tended to increase since 2006, probably because moving the rear wheels back relative to the chassis is a quick way of moving c.g. & c.p. forward without major aero mods. Probably made it easier to accommodate a larger fuel cell last year, KERS & pull-rod rear suspension this year. Shark fins have probably helped to recover lost weathercock stability.

Well i guess agility is grip limited. If it is that a longer car is giving you a certain return on downforce compared to a shorter design, the agility could balance out or even surpass that of the shorter car.

Before i make anymore guesses, what is agility exactly and what aspects of the car determine it?
Turning radius, inner to outer wheel slip ratio, wheel turning angle to grip relationship, toe, ackerman angle?

[DaveW]

Before i make anymore guesses, what is agility exactly and what aspects of the car determine it?
Turning radius, inner to outer wheel slip ratio, wheel turning angle to grip relationship, toe, ackerman angle?

An agile car will get into & out of a turn quickly. I'm sure the parameters you list are important either way, but it is not possible to "hide" yaw radius of gyration (proportional to yaw inertia/mass). A low value generally offers best mechanical performance, but can be more difficult to drive (exposes small driving errors). As a result, a less agile car often has an effective performance advantage in damp/wet conditions, for example.

[747heavy]

yaw damping is perhaps one of the things, which come to mind in this context.

If we take yaw as a moment around the vertical axis at the CoG of the car, and then
look at the "cornering stiffness" of our tires (keep in mind controlled tires), we can think about, what does it mean to provide a force (lateral force of the tires) in more or less distance from our CoG/yaw axis.

Sure it´s a bit simplified, as there are other considerations to take into account, but we should start somewhere.
I guess, this goes in the direction of Dave´s comment about stability & agility.

Sorry posted this before I read Dave´s comment above.
Also worth to remember that yaw damping changes with velocity (speed).
Normally decreases with an increase in velocity (think critical velocity).
Now downforce also changes with velocity, so perhaps there is an interesting cossover point to take into consideration. (low speed vs. high speed corners)

[Tim.Wright]

Agility or responsivness is typically the response time to an input. It can be somewhat quantifed in a test for a given set of operating parameters.

It is inversely related to yaw damping, so as 747h said, its also inversely related to speed and proportional to wheelbase.

So shorter wheelbase typically gives faster response because of the lower yaw damping.

Of course this is a simplified model so take what you will.

tim