BadDog said:
It wasn't "someone on Pirate", it was our own Triaged (Dan) who did that Excel file along with help from Greg. And the Peterson's article is somewhat useful in a very beginner sense, but there was SO much glossed over or completely ignored that it really serves as only a single partial intro at most. For some of the old links, look at the “top tech” sticky the top of this forum and search for some of the old 4 link threads in here as well.
When I did mine, it took a great deal of additional research and work to figure out what I wanted to do. The end result was superb, too bad I have not been able to enjoy it much...
Good luck on your project!
Actually that's close but not quite right......
ExcelCAD started out as a personal project based on that Peterson's 4WOR "Link Suspensions" article. I took their calculations and created a spreadsheet to model suspensions based on their assertions. After exchanging some emails with Dan (Triaged) about what I was doing he started teaching me basic Mechanical Engineering theory in his spare time (while still a student at Cal Poly) so that I would have the "vocabulary" to understand his suggestions for better ways to calculate things.
Dan wasn't much of an Excel guy at first, so I continued to send him files and he would double-check the math and send me feedback...often with changes made to improve things. Eventually, I did the graphical views (which I think were around v1.1 or v1.2) That's when Dan got really excited! He hadn't seen Excel used like that before, and basically I was creating CAD drawings to show the link positions and tire locations (which at that point weren't even round, more hexagonal!).
Shortly thereafter, Dan realized that he'd better teach me vector algebra so that we could model things in 3D space, not just 2D. That was a huge change to the program and that is when Dan became deeply involved and started spending a LOT of time working with me. The 3D models allowed us to show the top and side views and do a lot more with calculating FS values, etc. Plus, the aesthetics of the program were getting a lot nicer. Dan even figured out a way to draw the tires so that they'd be truly ROUND!
ExcelCAD continued to evolve and Dan was in his senior year of school at that point. I think he was able to use this program for some school credits, since it was getting pretty complicated and he had spent so much time on it.
Since Dan graduated, he has continued to mess around with ExcelCAD and has created and posted other variations since: 4-bar link and 3-link analyzer, and I have been working on refinements to the original ExcelCAD as well, though I haven't uploaded any new versions in a long time.
You guys did a fantastic job, sorry I got the credits screwed up. I'm getting old and the memory aint what it used to be. They say memory is the second thing to go... but I can't remember what the first was... 
