Re: CTM Racing axles - enquiry
Posted: Fri 09 Nov, 2007 8:35 pm
I think it has more to do with issues of wheelbase to track.
If you look at typical passenger cars the ratio is around 1.7 to 1.8, with sports cars around 1.6. This ratio decrease improves the responsiveness of the vehicle to directional changes but taken too far produces instability especially when coupled with a narrower front - effectively a truncated triangle which the rear pivots around, emphasised with uneven traction levels across the rear axle.
The Feroza ratio is 1.37 which puts it firmly in the twitchy category.
Its wider at the front now in an attempt to counteract the "triangle" trend a little, but of course that also hurts the ratio.
Its polar moment is also significantly greater than a sports car which also tends to damp its initial turning response a little.
So its worth doing the maths on track / wheelbase changes as it gives an indication of likely handling characteristics and their severity and prompts some thought about possible countermeasures.
Interestingly the very justified center of mass measure of moving the engine back decreases the polar moment which further decreases the vehicles straight line stability.
Damm modifications - so many things to consider ( or forget ) - so many compromises to make.......
If you look at typical passenger cars the ratio is around 1.7 to 1.8, with sports cars around 1.6. This ratio decrease improves the responsiveness of the vehicle to directional changes but taken too far produces instability especially when coupled with a narrower front - effectively a truncated triangle which the rear pivots around, emphasised with uneven traction levels across the rear axle.
The Feroza ratio is 1.37 which puts it firmly in the twitchy category.
Its wider at the front now in an attempt to counteract the "triangle" trend a little, but of course that also hurts the ratio.
Its polar moment is also significantly greater than a sports car which also tends to damp its initial turning response a little.
So its worth doing the maths on track / wheelbase changes as it gives an indication of likely handling characteristics and their severity and prompts some thought about possible countermeasures.
Interestingly the very justified center of mass measure of moving the engine back decreases the polar moment which further decreases the vehicles straight line stability.
Damm modifications - so many things to consider ( or forget ) - so many compromises to make.......