Thanks guys,
I went over to vvvortex forums and tried (probably in vain) to dispel some idiocy. Since what I wrote may be of interest to people here, I'm posting the same thing here:
All right...there seem to be a few questions, so I'll do my best.
First me:
I'm an 18 year old former high school student (now in college). I built the car over a period of 15 months, as the many blogs say. I spent a grand total of around $11000. I spent my entire life savings ($4000 or so) and worked for two summers to support it. Last summer, my schedule: wake up at 8, work on the car for an hour, go to work, get back around 5, and work till midnight or 2 am. It wasn't much fun, but I had to get it done before college. Also, I did it almost entirely alone - my dad thought I was crazy and no-one else in my family has any engineering experience. I contracted out the metal bending and the suspension bits were lasercut, but that's about it. I built a welder out of microwave ovens, which would work for 7 seconds before the circuit breaker cut in. I ended up having to put in my own 220v line and buying a real welder, before learning to actually weld.
Components:
yes, the components may not be spec for an Ar-i-el At-om. First of all, Everything that is on the car is there because of price. The reason it isn't 300 HP? Price. The reason I don't have carbon fiber things? price. The reason the front and rear black panels are actually cutouts of common plastic objects? Again, price. Many of the components are actually race spec components. The steering rack is from an circle track car, the ball joints are the exact same as those in the At-om, The steering u-joints are from the racing company Sweet manufacturing. Also, in many cases, there are a couple improvements on the At-om's design. The greatest improvement I made was in the bell-crank system in the suspension - I used tapered roller bearings in the cams. The At-om uses phosphor-bronze bearings, which tend to wear out quickly. Also, the friction created by the bronze bearings requires the shock valving to be adjusted specifically to compensate. On my car, the shocks are from (presumably crashed) four yamaha R1s. The shocks don't have as much travel as those on the At-om, but that's compensated with my cam system. Plus, you have to pay thousands more for the adjustable shocks in most race cars. The R1 shocks have 12 rebound and compression adjustments, as well as 200 lbs of preload adjustment or so. And, they're really pretty. And, they're around $30 each, compared to around 1000 each for a real one. They work just as well for what I'm doing. This is the same deal for basically every component in the car, from the shifter extensions to the throttle pedal I built from scratch. The only area where I didn't try to skimp was brakes. I'm using a Wilwood aluminum racing pedal set with four front Civic SI brakes.
But before I continue with the comparisons, it's worth nothing that I didn't set out to copy the Ar-i-el At-om. I set out to build a car that looked like the Ar-i-el At-om. The perceptive among you will notice that the difference is in the method. Instead of copying the At-om step for step, part for part, I had a general goal in mind.
Safety:
As some of you saw, I did crash simulations on a rough outline of the frame. It turns out that because of the lack of doors, the frame design is actually incredibly safe. I actually used thicker steel than that on the real At-om, but my welds are probably more suspect. The frame was one part where I didn't use "junk" as the blogs seem to say that I did. The frame is ERW 1018 steel. The roll bar material is 2.5" .120 DOM 1018 steel, which is larger that the steel used in most off-roader roll bars. The "Junk" was for several small things, like the body panels and the throttle pedal.
Suspension:
I spent three months learning about, understanding, and designing the suspension. I can tell you pretty much every angle.
KPI: 16 degrees.
Caster: 12 degrees
Roll center: 1.5 inches
Bump Steer (theoretical): .001" toe in over 5" bump
Bum Steer (measured: .1" toe out over 5" bump
The Suspension was the hardest problem I've ever solved in my life.
And so on and so forth. I had to deal with Camber gain in roll, ackerman compensation, scrub radius, steering axis, and around 10 more terms. I used a freeware program called Wishbone to do the suspension calculations. On a related note, I used Alibre Express (free!) to do the CAD model of the frame, and solidworks to do the suspension, once I found enough money to buy a real cad program.
Also, the At-om uses custom-made knuckles. I don't have the fabrication capability to make my own knuckles (uprights if you're British) So I had to build the suspension around these knuckles. Since the Civic SI knuckles are designed for a macpherson strut, converting them to double wishbone took a good 20-30 hours, primarily in CAD design.
Despite all this, it handles incredibly well. The steering is unbelievably sharp. The car doesn't randomly oversteer. The car is stable at 80 mph. (without alignment. I just eyeballed it, and it tracks almost straight) I haven't been on a race track, so I don't know if it oversteers or understeers.
And finally, prettiness: I had two weeks to do all of the bodywork and the painting. Also, I don't have any of the normal sheet metal tools: I have a hacksaw and a belt sander. Weirdly enough, wood jigsaw bits cut stainless much better than metal jigsaw bits. Even when dull. Don't ask- I don't understand. Also, it's the first time I painted anything. The paint didn't turn out so well. By the time the bodywork and everything else was done, I had 4 days left. 1 day (8 to 2 am) disassembly, 1 day painting, and 2 days reassembly (also 8-2am or so). My goal was to finish it at that point, not to enter a car show.
Once again, head on over to Locostusa to check out my build log. Also, check out my friend JonW's build log in the mid-engine vehicle build log "locost vtec At-om." He has a lot more experience than me. For pictures, register at locostusa.com. My log has a bunch of pictures
Any other questions? I hope I've answered a few. If you want to hire me, I'm in college right now, but I have a couple summers available.
_________________ "I've just been paid a visit by Q. He wants to do something nice for me."
"I'll alert the crew." (Picard and Riker)
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