engine placement

If you have infinite horsepower, acceleration is limited by wheel spin, so weight distribution matters... it controls down force on the driving wheels. That's why dragsters are long and have the engine forward, and have near zero down force on the front wheels off the line.

Is the new vette rear-wheel drive?

Why would any normal person want to accelerate madly and destroy expensive tires?

Kooks? On usenet? I'm shocked.

mandag den 24. august 2020 kl. 21.28.54 UTC+2 skrev RichD:

more of the weight is on the rear wheels, I think it is something like 40/60 instead of 50/50

You can overcome the classic coefficient-of-friction limitation by melting the tires and operating in viscous flow mode. If you can afford the insurance and the reckless driving tickets.

I knew a guy in college who got a Cobra. The original tires lasted one week.

mandag den 24. august 2020 kl. 21.48.00 UTC+2 skrev John Larkin:

maximum acceleration and braking is with something like 10% slip

I've never seen the point in such cars.

NT

For off-the-line acceleration, it's helpful if more of the weight is over the drive wheels, because for a given road surface and tire compound, the maximum drive force tends to be proportional to the normal force on the drive wheels.

During hard acceleration, the normal force shifts towards the rear wheels because the vehicle's centre of mass is above the road surface, which is why front-engine cars don't have the real-life advantage one would expect from this.

The real advantage of a mid-engine car is the reduced polar moment of inertia, which allows steering input to change the attitude of the car more easily. That helps the cornering and road feel a lot.

On the minus side, mid-engine cars are a huge pain to work on.

Cheers

Phil "stick-shift convertible Mustang" Hobbs

They're fun, if you have the money to spare and can fit in them. (I fit fine in Corvettes, but am a good six inches too tall for a Lambo.)

Cheers

Phil Hobbs

Front engine front wheel drive cars, that is.

Why?

Do you see the point in life?

Let me help you out :

"You only go around once in life, so grab for all the gusto you can"

So american, to get philosophy from a teevee ad -

probably some physicist that can explain why rubber acts like that

There's always the mid-engine supercharged minivan for the less flashy:

Very understandable. May I instead interest you in this lovely 1985 Chrysler LeBaron Mark Cross Town & Country edition convertible?

This beaut was one of Lee Iacocca's fever-dreams and might be up your alley

"Mark Cross" is not a name that I'm immediately familiar with or has recognizable luxury cachet for me, but it may have had some ritual significance or religious purpose to the humans of the time, rather like the process of cladding out your horseless carriage like a Viking longship.

Think of the surface pattern and rubber as a bit elastic brush and it starts to make sense. Or induction motor as we're in s.e.d.

(I used to work with guys who had made their PhD on tire friction..)

Oh, they seem to have moved some since I last looked. The wheel torque wants to lift the front wheels off the ground (that's good in a way, to move the down-force onto the rear tires) but that makes it hard to steer. I think they moved the engines back to keep oil and flames and chunks of piston out of their faces.

On a race track maybe. Do you race?

I've done a little competitive racing but it's like skydiving. The thrill is brief and the prep is extensive and you hang out with boring over-hormoned people. You *might* win a cheap plastic trophy.

Everytime a fuel dragster engine explodes (and they do that a lot) they spend kilobucks and weeks in a garage rebuilding.

I *hate* it when a circuit blows up. I'm very careful about probing. I gave my engineers a lecture recently about probe slips.

yes, and IME it has nothing to do with driving a road going car at nutty speeds.

I'm quite content to chill behind the wheel. Don't get me wrong I've had good fun on the track, but not gonna do that on the road, and have no need for daily adrenaline rushes. It has nothing to do with what's important to me.

NT

Flashy cars are for driving slow:

Not sure about rubber. But we may remember first year physics lab and that the coefficient of static friction is larger than dynamic. So 'just' slipping seems like it would be the max acceleration.

George H.