Build a car from scratch....

[Blue Bomber Man]

So after researching fuel economy for several weeks, reading countless posts, federal studies, academic studies etc I've decided that rather then making significant modifications to my current car (Mazda Protege '00) that I would like to custom design a car. I will likely decide to an electric car, presuming that I can design it to get 100 miles on a charge.

I'm planning on spending around two years in the design process of the car and the first decision I need to do is find a suitable design program that could handle a project of this complexity.


If anyone has any experience with some nice 3D design programs and could suggest some to look into that would be very helpful.



Basic Design:

Likely to be carbon fiber frame/body
-Lightweight
-More expensive materials, but easier to work with than steel
4 wheel, compact car - still need to decide on how many seats
Target weight ~1500 pounds;
Regen breaking
Possibly include solar
I will probably copycat the exterior design of the Ford Probe V (drag of .137!)

I plan on spending around two years of design before actually building it. If I find that it will be too cost prohibitive to build (or complex) then I'll scrap the idea before actually building it. I am planning on spending up to perhaps $15000 on materials and parts, most items will probably be new, but some things I may consider buying used.

Requirements of the design program: I would like it to be capable of exploding layouts from the main design to work on. Be capable of understanding material thickness, tracking weight changes, and perhaps cost as well.

Any help on finding this would be great =)

[Tango Charlie]

Google Sketchup is a 3D CAD program that's good to brainstorm with, but I don't think it's capable of some of your requirements.
Is this a personal project, or are you planning on selling plans/kits/complete cars?

[Blue Bomber Man]

Personal car, I doubt it would ever become a production car. I suppose if it is successful enough and someone wanted to pay me enough to build another one, I would consider it. This is all assuming that I go through with these plans. I will have some huge hurdles to clear just to create a reliable car that is road legal. Even if it was road legal, I would have to find a car that would insure it. After that if I was to build another for another person, I am sure there are other legal limitations dealing with safety testing. I would probably need some lawyer to write a disclosure and clause protecting me from a lawsuit.


In the coming months I will try to get a website up that hosts the design progress and will allow people to comment on different design issues. Hopefully this will speed up the learning curve designing a car and will maybe generate interest in the vehicle. I will try to have some advertising on the site in a modest unobtrusive way to cover the expenses of running a site and if enough interest is generated, perhaps help fund the car.

For now I will spend a week or so researching design programs to find out what is best suited for this project. I looked up some programs earlier and sketchup was the first to show up on the query. It seems pretty good for some aspects, I really like the ability to scan an image in and then model around it. Would be extremely useful for copying the probe's aerodynamics. But in other regards it feels limited for something of mechanical design.

I found a program after that that is actually used by a car manufacturer Commuter Cars Corp to design their car. Here is a link to the video:
SolidWorks :: SolidWorks Customer Success Stories and Testimonials

The program definately seems suited for designing a vehicle. I just need to find out if it can also track weight, perhaps center of gravity, and costs.

[Memorytwo]

ariel atom?

[Hasbro]

You'll get some great direction here: :: Index

There are EV Forums also.

[Coyote X]

You would be much better off sticking with an already existing car and redesigning it to your needs. You can make your own suspension arms and whatnot and just keep them the same dimensions and specifications as the oem parts if you want it totally custom.

My first car I basically scratch built was built about like you are thinking of doing. It worked out ok initially. I used custom modified parts from about 15 different cars to build it on a custom frame and everything. The problem comes in as soon as you actually start driving it and things break you have to figure out where to find a replacement part and what it came off of. If you have a huge number of custom parts then it is likely the broken part will have to be custom made again and you will be out of commission for how ever long it takes to make a new one.

If you take an entire existing car and use only parts for it on your build then 25k miles later and a year or two when it breaks down you can easily fix it instead of digging through your notes to figure out how to remake the part. You can change the length/width of a car that started out as a unibody pretty easily if you make your own frame. CV axles are very simple to lengthen or shorten. Pretty much any other measurements can be altered at will with the new chassis. Shift rods can be converted to cable operated so the transmission doesn't have to stay in the stock location either.

For a car that gets no real use and is mostly for show then making the entire car from scratch is great and you can go wild with the designs. But anything on the road a lot is going to break down and when it does you won't want to have to spend every second machining out new parts to fix it.

[Blue Bomber Man]

Hey, thanks for the detailed response. It was actually one of your build threads that inspired me to build the car. I've actually put a lot of thought into this project and I think that I can build a capable and reliable vehicle.

The 3d design program I am probably going to use is absolutely incredible from the propoganda I found on their website. Complete power over design, specs, weight, stress loads, collision of designed parts, and on the fly rendition of changes.

As I design and research the endless possibilties for this car I will track material costs, tools required, and a *very* rough guestimation of time to build. I am planning up to two years in this design so that I will have a solid understanding of what will be required and will refrain from actually buying any parts until I feel that the car will meet my specifications and within budget. Once I commit to building the car I will seek out sponsors for parts.

Additionally I will host a website dedicated to the whole process of design, costs, ideas and implementation etc. I will host some unobtrusive advertisement and a forum to discuss ideas. Hopefully I can create this website to be informative and attractive so that it helps generate interest in my project and perhaps some funding.

[Blue Bomber Man]

Some good news on the software front: SolidWorks does have student pricing ($150.00) which is about 96% off the retail price (and that is not an exaggeration).

Additionally he stated I might be able to get a discount on the full version based on my projects intentions. The only differences that I know of between the two is that the student license expires after two years and cannot be used commercially. When I talk on the phone with the rep I will have more information on this.

[Doofus McFancypants]

Have you considered some of the KIT cars?
they are pretty customer already - and many have a base offering of the frame / body from which you can then customize.

I like the Lotus 7 kits (:: Index)
some guys have modified to be electric

Some of these guys have built the frame from scratch - there are many existing plans available so you do not have to engineer the basic frame - ( NOTE you WILL have to get into the details for the suspension geometry though)

This takes MOST of the guesswork out. ( although Lotus 7 is NOT very aerodymanic - but for intown electric driving - it would be really ciil

[Blue Bomber Man]

In an above post someone mentioned that kit, so I went to the forum and looked around to get information. Really seems like a neat car, but it is not suited for what I want. I need my vehicle to self enclosed and capable of at least one passenger (will likely design for 4 though).

I did some preliminary research on batteries today, Lithium Ion Polymer batteries seem very well suited for a vehicle based on power/weight ratio. I need to learn more about the life cycle of the batteries based on charge cycles. One battery was quoted at 300 cycles, which seems low if that means I could only charge it 300 times total before having significant losses (20%) Additionally they are very expensive, but because of the extreme weight savings it would allow me to downsize other design specs and potentially reduce costs and improve efficiencies.