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  1. Bluefoxy

    Roll center migration

    Hello Norm, 'I suspect that lateral RC migration is really an indication of something as opposed to an end in and of itself. If the RC isn't moving very far, that means the inclinations of the force lines from the contact patches to the FVICs can't be varying much. Which sounds to me that the...
  2. Bluefoxy

    Roll center migration

    Dear Ubyvisi, On this kind of suspension, where toe link is weld on the upper wishbone. From my experience , we put a little bit caster at the rear, may be 1-2°, to get a bit of toe in in bump (+0.2mm for 1 inch bump). With this small angle, the resultant vertical effort on the upper...
  3. Bluefoxy

    Roll center migration

    Hello Norm, 'I suspect that lateral RC migration is really an indication of something as opposed to an end in and of itself. If the RC isn't moving very far, that means the inclinations of the force lines from the contact patches to the FVICs can't be varying much. Which sounds to me that the...
  4. Bluefoxy

    Roll center migration

    Ubyvisi, I know well Formula Ford, I worked from 2001 to 2006 at Mygale design office. Regarding rear caster, from side wiew if you isolate wheel + upright, you put vertical and longitudinal load on the wheel contact.For push rod, Upper uright point will carry longitudinal load, and lower...
  5. Bluefoxy

    Roll center migration

    Hello UBYVISI, Thank for your experience feedback. What kind of racing car did you experience this? Regarding rear caster, like for a formula ford style suspension, it is a way to set the bumpsteer. Increase caster go for toe in in bump, decrease toe out in bump. Regards N.Maurel
  6. Bluefoxy

    Roll center migration

    cibachrome Thank you for your reply. But I must admit I did understand a few bit of what you explain. 1. English are not my native tongue, and most of time I have to use google traduction to understand, so I might lost the sense of your meaning. 2. I m not a sim specialist and I do not have...
  7. Bluefoxy

    Roll center migration

    "It is not the case on race car where suspension are rigid joint" While it would be possible to build a racing car that has a structure as stiff as a ball joint, it would not be competitive. I meant rose joint not silent block like production car
  8. Bluefoxy

    Roll center migration

    Brian, I assume you mention this kind of graph So if I well understand built up of geometric force (partially depend to Rc-CG) come fisrt with no movement of the suspension (no roll), then built up of elastic force (mainly dependent of spring, etc) with movement of roll. As soon as no...
  9. Bluefoxy

    Roll center migration

    Buggar, Nice job. but: 1. If you isolate a wheel with upright, sum of the force apply to W+U must be zero. This mean line force upper link, line force lower link, and line force from the tire contact must be concurent on a single point, otherwise your system is not static. More clearly you...
  10. Bluefoxy

    Roll center migration

    'In other words, this really needs to be looked at using a time history approach rather than 'before' and 'after' snapshots' You are rifght but my calculation are static not dynamic. What mention Cibachrome is tested to see the dynamic of car. First those test are for production car, all the...
  11. Bluefoxy

    Roll center migration

    Sorry but nothing is attached
  12. Bluefoxy

    Roll center migration

    I m not trying to sell anything. I find a way to design a twin arm with Rc not moving, which many author claim it is a good thing. honestly I have no clue if it is good not or not, so my initial question on this thread. I never give an attention to FBRC concept, because as far as you deal with...
  13. Bluefoxy

    Roll center migration

    At least, recognize FBRC-CG stay constant near the ground!
  14. Bluefoxy

    Roll center migration

    Brian, Regarding Mac Pherson, I take the time to DRAW, because DRAW help me to understand what happen. Regarding the position of FAP, it stay constant until the lower arm get the same angle as the perpendicular to the upper strut mount, if it come more angle it went totally opposit. Both...
  15. Bluefoxy

    Roll center migration

    Brian, So I do not understand why you do not like the concept of twin arm suspension with constant distance RC-COG. Because as far RC-COG remain constant, both FAP are very near (you even do not have to negligate the inside wheel), it result a FBRC -CG distance constant:
  16. Bluefoxy

    Roll center migration

    Brian, As I far I understand, with few degree away from the vertical, It make an IC wich move on a line which nearly horizontal, which leads to a line Center of tire-IC, which is also quiet horizontal. As the suspension compress (outside wheel) ,tire-IC went even more horizontal. So FAP of...
  17. Bluefoxy

    Roll center migration

    Greg, You are agree with Mitchell, when he wrote: 'Stability results when the FAP-CG moment arm remains constant as the vehicle rolls. The chassis “takes a set” rather than constantly seeking a new equilibrium. This can be expressed by minimizing the lateral movement of the KRC as the vehicle...
  18. Bluefoxy

    Roll center migration

    And you still see any any interest of my suspension with nearly constant distance from RC-COG?
  19. Bluefoxy

    Roll center migration

    Greg, You think FBRCH is an useful definition?
  20. Bluefoxy

    Roll center migration

    Buggar, The location at which the lateral force may be applied to create a roll moment about the center of gravity of the chassis equal to the chassis roll moment induced by the individual laterally loaded tires as transmitted through the suspension links to the center of gravity of the...

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