Maybe someone smart can chime in. I've been trying to design my dual swing steering from my desk for a while now. Just keeping things static right now and I'm going nuts.
My process is create an axis through the passenger radius arm pivot and beam pivot, and create a line perpendicular to that axis that goes through the steering arm. From that I am able to create an arc the steering arm makes as the suspension cycles.
Along the original radius arm/beam pivot axis I made a grid of points that I am able to use to as inner passenger tie rod pivot locations, making the arc a tie rod would make. The deviation between the arcs is how much bump steer would be induced. I am measuring at 8" bump and 8" droop, since that's how my front is set up. To get the best results for arc intersection, I believe the arcs should be of equal radius, pivot as close to each other as possible, and both pivoting about the same axis.
I'm not terribly thrilled with the numbers I'm seeing. This setup shows about 1/4" bumpsteer at bump and over 1/2" at droop. Measuring at the tires amplifies those numbers. Anyone have any thoughts? Anything I'm missing?
Front
Bottom
Looking at the passeger corner
I may end up trying to break up the scan into individual parts so I can make each part a solid body and allow everything to pivot around. I feel like that's going to suck but is the next step to make sure things clear