Car Wars Tournament at Emerald City Comic Con

[Chernobyl]

Originally Posted by 43Supporter

It's "The C. F. Memorial Arena", from _Car Wars Arenas_ -- slightly modified, as the way the original is drawn it isn't actually possible to have the corners banked as described....

I'll have to find my copy for the description :)
as a civil engineer I'm curious to see how the superelevation is not possible.

[43Supporter]

Originally Posted by Chernobyl

I'll have to find my copy for the description :)
as a civil engineer I'm curious to see how the superelevation is not possible.

The track is 4" wide on the straights, but is upwards of 5&1/2" in the corners.

The "ground level" forms one side of a right triangle; the vertical wall forms the second side (making a right angle); the track surface itself forms the hypotenuse.

If one measures 4" out from the inner edge of the track, then, one reaches 4" well before one reaches where the outer edge of the track is shown; that's where the top of the banking would be.

If one attempts to draw the banking to where the outer edge of the track is shown, one ends up with the banking in the corners being considerably less deep than in the straights; which leads to the straights actually being "humpbacked" (which will do *very* interesting things to cars driving over same at speed -- in German, it's called a "Flugplatz"... >:) )

If one tries to draw the banking from the outer edge of the track, one reaches a point (literally) where the banking has to perform a 90-degree turn in order to follow the track -- and that would be *really* interesting to drive through (can you say "wall"?).

In short: It is not physically possible to build the track as-described in the manual.

[Magesmiley]

Originally Posted by 43Supporter

The track is 4" wide on the straights, but is upwards of 5&1/2" in the corners.

The "ground level" forms one side of a right triangle; the vertical wall forms the second side (making a right angle); the track surface itself forms the hypotenuse.

If one measures 4" out from the inner edge of the track, then, one reaches 4" well before one reaches where the outer edge of the track is shown; that's where the top of the banking would be.

If one attempts to draw the banking to where the outer edge of the track is shown, one ends up with the banking in the corners being considerably less deep than in the straights; which leads to the straights actually being "humpbacked" (which will do *very* interesting things to cars driving over same at speed -- in German, it's called a "Flugplatz"... >:) )

If one tries to draw the banking from the outer edge of the track, one reaches a point (literally) where the banking has to perform a 90-degree turn in order to follow the track -- and that would be *really* interesting to drive through (can you say "wall"?).

In short: It is not physically possible to build the track as-described in the manual.

For an even height, the outer corners need to be in further in. If I were building this, I'd take some creative license and do exactly that to fix this. Start from 2" in from the corners in both the X and Y direction. Use a compass from those points and draw a 2" and 4" quarter circle (the inner side looks approximately right).

If you're doing a triple scale map, that would be 1' and 2' respectively (a piece of string and two pencils are useful for doing this). This should give an even width for the track all the way around (1' on the base). The outer edge of the track should be 4" high according to the description, which gives an actual road bed of 12.65" on the angle.

That's how I'd tackle it anyways. Voila.

[Magesmiley]

Hmmm. This wouldn't actually be that hard to build really. (Drums fingers...)

[43Supporter]

Originally Posted by Magesmiley

For an even height, the outer corners need to be in further in. If I were building this, I'd take some creative license and do exactly that to fix this. Start from 2" in from the corners in both the X and Y direction. Use a compass from those points and draw a 2" and 4" quarter circle (the inner side looks approximately right).

I had a 3D version made a while back -- if one takes the inner edge of the track as "baseline", and moves 4" out from that, one gets proper banking; the "extra" on the outer edge can be disregarded.

(This would be far easier to discuss if I could post pics here, but "the world is what you make of it -- if it doesn't fit, you make alterations". :) )

[Chernobyl]

In a real world situation the full bank angle is only developed in the turns. In and out of the curves you have what called superelevation runout which is a transition length between full super and "normal crown" which is 2 percent slope (small amount of angle to allow rain to drain off the roadway) though since a racetrack is one way it is probably not really a crown. the length of the super runout depends on the difference in angle and the design speed. On the short straights you might not get back to normal crown.
However when you measure road width, you always measure top down, not along the angle of the super (hypotenuse)

there's a decent diagram here
http://mes100.com/blog/transition-length-benchmark/

[43Supporter]

Originally Posted by Chernobyl

In a real world situation the full bank angle is only developed in the turns.

Not necessarily -- there's a velodrome up here which is (was...) also used for quarter-midget racing; it's a consistent banking all the way around. I think there used to be some full-size-car tracks like that, but none exist any more; closest I can think of are Bristol M.S., and Dover Speedway.

[Chernobyl]

Originally Posted by 43Supporter

Not necessarily -- there's a velodrome up here which is (was...) also used for quarter-midget racing; it's a consistent banking all the way around. I think there used to be some full-size-car tracks like that, but none exist any more; closest I can think of are Bristol M.S., and Dover Speedway.

Dover and Bristol both flatten out on the straights. Dover from 24 deg. to 9 deg., Bristol from 26 deg. to 6 deg. (wiki)

[43Supporter]

Originally Posted by Chernobyl

Dover and Bristol both flatten out on the straights. Dover from 24 deg. to 9 deg., Bristol from 26 deg. to 6 deg. (wiki)

That's why I said "closest" -- I think even a straight banked half as much as the corners at Bristol, or Dover, would be too much for stock cars.

At any rate [ahem :) ]: The "CF Memorial"'s desc. says the banking is constant all the way around, so that's what I'm working from; and the ways the corners are drawn, It Don't Work, Mate. :)

[ChargersWI]

If you want velodrome-like banking, that's Slinger Speedway. 30 degrees in the corners and 28 on the straights.

https://www.bing.com/videos/search?q...tail&FORM=VIRE

https://www.bing.com/videos/search?q...0&&FORM=VDRVRV