Originally Posted by
AndyP
I would be VERY greatful if some of the tech`s out there could share some of their knowledge and give me some pointers on where to start when designing suspension,
In the past we (formula student team) have began by deciding on the track and wheelbase dimension, then moving on to the length of the wishbones then proceeding from there. Is this right???
Also what about unequal wishbone lengths - is this a good idea and why?
Thankyou, Regards
Andy
Andy, as much as we'd like to help, you've just asked for a complete year of an automotive design course as one post in an on-line forum
Anyway ....
track and wheelbase are as good a place to start.
BUT there is a first question and that is PURPOSE.
What is the car for, what do you woant it to do, what performance, handling, comfort over waht surfaces.
There are some excellent books on sports car suspension design and some have been copied onto peoples web sites ( quoting it as 'theirs' in many cases ). Unfortunately, mine are all out at friends who's been looking at adjustments for his 7-copy for track.
We've had a couple of the online ones quoted in other threads on UCP, but I can't find them quickly. You may want to do a search of the forums and spent a wee while reviewing.
Happy to try best to answer specific questions
On unequal wishbones, the benfit is the way the camber of the wheel caries over the movement of suspension. So you can use this in conjunctino with body roll to present a more stabel tyre contact location with the road. As the contact point varies it alters the car handling and resistance. Also by offsetting the wishbone pivots, you can also make anti-dive characteristics under braking.
Best advice I can give ( beyond reading the many books available ) is to use modern tools to better grasp the concepts and effects. So do all the design in a 3d engineering CAD package where you can move the elements and they will pivot/rotate as they would in real. Used to have to do this with drawing boards consider yourself lucky !!! So you can play with geometry and mounting and see how suspension movement affects wheel orientation, location and contact with the road. Egg-Nog has shamed me in the engine stroke posts with my lack of pictures. So I'll see what I can manage to help illustrate
"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'