making FWD rotate

[sids]

here's an interesting idea

FWD are usually prone to understeer and don't rotate about the axis as easy as rear wheel drive cars.

I was in a slalom yesterday and noticed a proliferation of short wheel base cars tearing up the cones.

what if there was a way to increase rotation of the outisde wheel as compared to the inner wheel then rotating would be extremely easy.

In some ways LSDs do this but with the coming advent of independent electric motors in wheels, mitsu evo concept, where instead of an engine, there is an electric motor in each brake assembly.

you can then control front/back rotation, and make the car rotate about it's axis like a tank.

[Reed]

i think there was a formula one team that did this at one point or maybe it was some other sports car series. not sure i just think that i may have heard that before. can anyone verify?

(edit)except they did it without electric motors(edit)

[mazdatech177]

wellllll, if both wheels are independant from each other then the outside one already rotates faster than the inside one, if it didnt the car would skip around the corner. LSDs allow some slip (though sometimes not enough) to avoid the chirping around corners but still have the two drive tires effectively locked together. i think subaru or someone that uses all wheel drive technology already has a power distribution system that already accelerates the outside wheel in a corner to improve handling..... maybe its audi...

[beyondloadedSE]

you could add a larger rear sway bar and essentially do the same thing.

[Moppie]

Originally Posted by mazdatech177

i think subaru or someone that uses all wheel drive technology already has a power distribution system that already accelerates the outside wheel in a corner to improve handling..... maybe its audi...

Mitsubishi developed a system called Active Yaw Control that does this, altough Im sure its now used by other manufactorers.



A stiffer rear sway bar, or rear suspension is an old trick, although it dosn't actualy rotate the front wheels, it simply reduces traction to the back wheels, allowing the car to rotate about its centre of gravity a little easier. Effectivly the back wheels end up doing very little, maybe provide a little bit of directional stablity when going straight, but since they are not driven they are considered dead weight, and so the idea is to get as much weight off them as possible and use only the front wheels.
Honda have made it work very successfuly, and I know during the 80s and 90s the factory race teams had a simple forumula for caluculating rear spring rates, the just used Twice the front spring rate.



A differential allows two wheels on either side of a driven axle to turn at differnt speeds as the out side wheel tracks a longer pather around a curve, what sids is suggesting useing independant electric motors on each wheel to force the out wheel to turn faster effectivly forcing the car to rotate into a corner, it's exactly the same princable used to steer a tank, just a little more subtle.