Tandem front axle
Tandem front axle
(OP)
I was looking at the Covini Engineering C6W:
http://www.coviniengineering.com/english/c6w_1.htm
and had some questions/thoughts, regarding the engineering theory behind the use of tandem front axles...
1) Do you reduce the front spring rates by 1/2, since you have twice as many?
2) Ackermann must be interesting to figure out, with 2 turning sets of tires.
3) Does oversteer increase, with twice as much front contact patch?
Any thoughts on this?
http://www.coviniengineering.com/english/c6w_1.htm
and had some questions/thoughts, regarding the engineering theory behind the use of tandem front axles...
1) Do you reduce the front spring rates by 1/2, since you have twice as many?
2) Ackermann must be interesting to figure out, with 2 turning sets of tires.
3) Does oversteer increase, with twice as much front contact patch?
Any thoughts on this?





RE: Tandem front axle
1) You would indeed reduce spring rates by something close to half. The pair of springs on each side of the twin axles act in paralell, so their rates are added together to produce the desired rate to support the corner weight. The text mentions the use of hydro-pneumatic front suspension, and its use in contolling weight distribution between the front wheels. This suggests some coupling between the axles, possibly involving a shared (gas) spring.
2) Ackermann (and steering rate) is calculated for each axle with respect to it's distance from the rear axle(s) centre.
3) The increase in contact patch will tend to increase oversteer, all other things being equal. All other things will not, however, be equal.
Looking at the pictures, I would suggest that the total front contact patch is probably not much different to that of a more conventional sports car with larger diameter, wider front tyres.
Interesting project, nevertheless.
Pete.
RE: Tandem front axle
RE: Tandem front axle
MarkEE
RE: Tandem front axle
Regards
pat
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.