Recent content by electrodruid

Thanks, all. I've learned that the friction coefficient is used to set a limit on the car's tractive force rather than act as a multiplier for it, and that rolling resistance is... complicated, but does differ according to surface type (even if overall the effect is probably extremely subtle). I...

Here's what I'm trying to get to the truth of. Bystander says that rolling resistance is higher on wet roads than on dry. Can anyone confirm or refute this idea? This is the only place I've heard that idea expressed. If it is true, can anyone shed any light on exactly HOW rolling resistance...

My simulation doesn't really include engine power. For long, complicated, and not-terribly-relevant-to-my-question reasons, the tractive force is approximated from a sort of idealised mathematically (rather than physics-ally) constructed acceleration curve and the resistive forces. I don't...

Hehe. I always make that mistake first time around, too :)

Ah! Perfect! Thank you! Okay, so what about the other part - the idea that there's some kind of change or addition to the drag forces on wet or slippery surfaces, so the top speed of the car is perhaps still affected somewhat compared to dry conditions (but not affected directly by the...

For a given velocity v, my force calculation currently looks something like this: F = (TractionForce(v) * frictionCoefficient) - ((DragCoefficient * v * v) + (RRCoefficient * v)) So with a friction coefficient of 1.0, i.e. a dry road, the available tractive force isn't scaled or limited in...

Understood. Perhaps I need to clarify how I'm currently doing things. So I've calculated the propulsive and resistive forces for a car on a dry drag strip - friction coefficient of 1.0. So for a wet drag strip I'm just looking up those same numbers I calculated earlier, but multiplying the...

Interesting. So to summarise, there's a threshold speed/gear above which the friction coefficient becomes effectively irrelevant and the car's top speed is instead limited by rolling resistance (or some additional drag force) instead? That raises some questions: - How might you go about...

I'm a games programmer who is writing a simple car physics simulation, and I've had a disagreement with the designer about a car's behaviour - specifically, its top speed - in different conditions. Imagine a car accelerating from a standing start to top speed along a perfectly straight, flat...

Thanks for clearing up how to run the numbers through the formula, but I still don't feel like I'm getting to the root of my question. In fact, this is raising more questions than it answers... The equation doesn't seem to take the tyre composition into account (unless the main difference in...

This? I did miss that first time around. But... What IS that? What do all those "magic numbers" mean? Might they vary, or are they magical constants of the universe? How can that be adapted to m/s rather than km/h? I'm having trouble even wrapping my head around the order of operations. EDIT...

I already linked to that page in my original post :) The claim from that page that Fr = c W kind of makes sense, except I'm confused by the fact that there's no velocity in that equation. What's the rolling resistance for a stationary vehicle? Or one moving very slowly?

I'm a games programmer working on a (simple, so far) physics engine for a driving game. Right now I'm interested in acceleration, and in particular trying to estimate the forces that go into it. I've got basic data for a bunch of cars (0-60 time, 0-100 time, top speed, mass) and a brute-force...

Thanks, this is all really helpful. So if I'm reading the Tyre Load Sensitivity issue correctly, even if you did put the same tyres on the Land Rover and the Ferrari, the Land Rover would still have the bigger stopping distance because its additional weight would have a detrimental effect on the...

Can you elaborate a bit about why this is the case? Is it because the fastest way to brake is to have the brakes apply as much force as possible without locking the wheels? A bigger contact area between the tyres and the street means more static friction, so you can apply the brakes more heavily...