snow/ice racing.. four wheel steering?

[FussyFez]

Im sat watching motors tv.. 'trophee andros' champs. It seems that these mental little motors have 4 wheel steering... Could anyone confirm im not seeing things? By 4 wheel steering I dont mean active yaw control. The rear wheels appear to be turning like the fronts..

[zac510]

Yes they definitely do. They rear wheels only steer when they get to a certain angle of front lock. If you like I might be able to dig out a pictur of the mechanism from a few years ago. Although then there were two common solutions.

Its effect and intentions are not dissimilar to a handbrake on a rally car - it transfers slip angle to all 4 tyres quickly to turn the car into the corner.

[woof]

yep - spot on.
I got an invitation to drive one a few years back at Val Thorens.

Believe it or not it wasn't too difficult. Studded tyres, 4 wheel drive/steer. Of course to be fast is another level.

[FussyFez]

Cracking stuff. I was wondering if it was a constant thing, mechanicaly connected to the steering rack, or if it was a driver activated thing that could be turned off.

Thanks for the informative replies guys!

[zac510]

It's mechanically connected.

One method has a steering-connected shaft that ran longitudinally down the car and rotated a flywheel-sized aluminium disc that sat on the end of the shaft. Cut into this disc is a spiral/snail shell shaped channel and a solid steering rack was located by a pin into this channel. As the disc rotated and the channel moved closer or further from the centre of the disc the pin would move with it and the rear wheels would move.

Can't get a pic at the moment, it's on another hard drive. Let me check Google images.

[mrmr96]

zac510 said:

Can't get a pic at the moment, it's on another hard drive. Let me check Google images.

Please do if you can, sounds interesting.

[FussyFez]

I can picture what you mean. Are there any other forms of motorsport that use it? Would it not be usefull in rallycross or even tarmac events?

[zac510]

Sorry about the best I can find is this picture:


You can see the disc behind the V of the engine.

[Richard-G]

zac510 said:

Sorry about the best I can find is this picture:


You can see the disc behind the V of the engine.

add in a side window wiper and i wont be able to sit up for a while!