Track Designs: Curve Radius

I've been working on some future track designs, and through research and discovery of what others have done to their tracks, I started putting some of those ideas to use. One in particular would be designing curves...in particular the "Big Curve".

For software I use SoftyBahnplaner because it is free and has Carrera sizes. http://www.softyroyal.de/?t=22c24290

Since I know I want a big curve on my track, I naturally started off with the largest radius of the curves and built one of all 4/15 pieces:

The gray backdrop is my proposed depth of 166 centimeters, or 5.44 feet. That's a bit deeper than a ping pong table. The 4/15 track pieces put together won't fit on that layout, and that's without consideration of borders. 

4/15 is a big big curve. In order to make it work satisfactorily, I'd have to go smaller. Here was my next option:

The 3/30 curve. This just fits in the layout, but likely wouldn't handle borders. It's still a big turn, and can probably still be fun, but there's something about it that just isn't right.

So, I have a conundrum: the layout is smaller than will allow for the size curve I want to make. Plus, having such a strict radius on the curve is a little boring, and a bit unrealistic. In real life, probably the only racetrack that featured such a curve was the AVUS racetrack in Germany, and that was banked. In order to avoid the uniformity of a single-radius curve, here is where the use of varying radius track pieces will help, as well as add more interest for the driver:

Here is a curve using 4/15s [blue], 3/30s [green] and 2/30's [yellow]. The lone straight track is where the previous curve ended up. The width is significantly less, and can now safely hold borders all the way around. The turn is still perceived large, but the ever-shrinking radius going in will allow the cars to pitch out and handle the turns more naturally.  Of the three, this one I feel would be the most interesting to drive.

Now we're getting somewhere. It doesn't necessarily have to be big, but it does have to be interesting. By adding a little variety to the curve radii I think I have achieved that. Of course, this can be used for smaller curves as well:

With a 1/60 curve at the apex, this one will sneak up on you if you're not careful. Gradual going in and coming out with a quick snap at the peak. Lots of room for scenery or other options.

So it's really going to come down to making curves interesting enough to keep me entertained as well as small/large enough to fit practically on the layout. Variation can lead to all sorts of ideas. If I don't want the in and out to be so flat, I can always tighten it and run the straights a bit closer together. Like this:

Talk about a curve with great flow and a bit of excitement. It comes back on itself, which allows more tightness and technical skill. Plus, it really gets away from the generic 90ª curves that people tend to settle on. 

Loads to think about. My track will definitely feature variable-radius curves. This will make the difference between a track that flows and a track that doesn't.