Quote:
Originally posted by TNT1
Finally read through all that and it made my head hurt…..lol! I'm a 25 yr Aircraft Design Engineer and think in way more detail than this and design products in the $750,000,000 dollar range, not $15, 000. I found the material 400EXRider707 presented for the most part very well thought out…….I can tell you have a good mechanical aptitude and can visualize geometry well. I do that all day with very sophisticated computer graphic's, CATIA and loads models NASTRAN. We develop designs, test them, put them into production similar to the quad industry but to tighter tolerances, more advanced processes and testing since we can't have planes falling out of the sky can we.
400EX has some practical experience with some of the quads, and with others has theorems he appears to be using based on a geometrical analysis. All good but in all practicalities, every quad/racer/track has many variables that can change theories in effect. The quad geometry and the track, the rider will impose loads on that geometry that 400EX has not validated by testing methods such as stress/strain gages, other gage testing such as handle bar reaction, tire reactions, ball joint fatigue, etc, or mathematical statics(free body diagrams) or dynamics equations………Not to undermine 400EX theories, again some are proven by him and others, but just bear in mind to take all this logic(which is again very well thought out and good) and go test it for yourself. Outside of test fixtures the best way to learn about these theorems is to develop empirical data. We do this often, collect info, results over time then we put that info into computer models and use it to design, or in our quad case change our set up and note the effects. He has made that statement a few times thoughout this thread, try it yourself and I will add tabulate and track your results. Thats what I do I have set up data for most tracks we run MX and flat track set up is even more complicated with a sway bar. I think his intent was to awaken everyone as to the thought process that goes into the design and geometry of a quad and he is doing a very good job!
Still not sure I agree with you on a few things like the effect of wheel inset and tire size on bumpster..In all practicality I think it is minimal, in theory I see a conical effect that will vary depending on all the load paths imposed. Again those loads due to the variables, tracks, rider, quad geometry can have varying effects. Without a good load and kinematics model hard to say.
We have an engineer here that quit and went to work on a NASCAR team….they GPS the track solid model the car to a kinematics(motion) CATIA/NASTRAN loads model including a model of the racer for ergonomics. They can take the front end change the geometry in the computer and see the actual load on every square inch of say a tie rod, tires(hard due to the spring rates), ball joint, steering wheel, cornering, handling, etc…..then go test it and bring that data back to the computer. I have considered offering this service to a quad pro but the money in NASCAR is much greater they can afford it.
Anyway good thread….I'll try and help if I can.
Thanks!
Thanks for the input and the kinds words. Most of what you're talking about is way over the head of the every day rider. I tried to keep it technical, but still understandable. I think I did a decent job of that. I would love to talk more technical with you. You obviously have better resources than I do, but I understand what you're saying and can definitely follow along.