First thing I did (sorry, no pictures here), was to make a half pattern for the floor of the car. I took some points off of the drawing I had made up and marked them on a piece of 3/4" scrap plywood I had lying around. I then used a thin strip of wood (in this case a piece of 1/4"x1/2" cap strip from my airplane wood) to draw a curve that matched up with all the points I took from the plans. Used my crappy little jig saw (really need to get a better one) to cut out the shape, and then faired up the curve with a rasp plane and a sander.

The pattern is used with a following bit in the router to make the actual floor of the car. Once you get one side done, you can flip the pattern over and do the other side, which should make them exactly the same (that's why you use a half pattern, see?)

There are 3 bulkeads that define the real shape of the car, and a couple extra bulkheads for the seatback and steering/wheels support structure. They are put together out of 3/4" Plywood, and 1.5" x .75" nailing cleats. I made a mistake in measuring them out, so we decided to save the half round bits that go on top of the bulkheads for later.

If you're designing something like this yourself, always make sure that you can fit in it, and no parts of the car go through the middle of your leg. This is more difficult than you might imagine.

Between the seat back and the rear of the car, I put in space for a motorcycle engine to be fitted maybe one day. The Seat back is an interesting piece, since it angles back, it has 2 seperate angles to be cut on the sides, a bit tricky. Actually, you could make it even trickier on yourself, because there should be a slight curve to where it meets up with sides as well, but I left that out and it seems to work fine.

We determined the curve of the sides by lining them up with the side of the car, marking where the floor and bulkheads went on the sides, and then making curves with a thin piece of wood like I did for the floor. Then the same drill with the jigsaw, router, etc...

Notice how we carefully matched the bulkheads to the floor so that the sides will have plenty of gluing area when we put them on.