The increasing radius turn

[jhigdon]

Ok, this has been bugging me for a while, and I've talked to a few older SASCA members who used to design courses and drive from the mid seventies all the way through the mid nineties and that has only increased my curiosity, why not the increasing radius turn?

I have yet to see an autocross course with a pronounced increasing radius turn, and I can’t see a good reason why except that they simply aren’t thought about a lot. The way I see it a good increasing radius turn would have a generous speed buildup, followed by a tight turn entrance, leading into a tightly sweeping but still increasing radius curve leading into a speed critical area of the course, something that would make it very important to carry speed out of the turn, something like a high speed slalom or a short shoot. Any reason why this wouldn’t work? A turn like this would test the car/driver combo in many ways, braking into the turn, being alert for push into the turn, being alert for throttle oversteer as one accelerated out of the turn, while at the same time demanding a driver carry as much speed as possible so as to not lose speed later in the course.

Is there someone that has a map of the Verizon lot I could use to map out approximately what I was thinking off?

[mroberts]

PM me your preffered file format and an e-mail address and I'll send you the template.

[Richard Watson]

James,

Depending on your line, many of the turns from sundays's course could be increasing radius.

Turn 3

Turns 4-5

Maybe the hairpin (depending on your car)

The sweeper after the walls and 3 cone slalom leading into the long slalom.

Richard

[snowman0520]

quote:

being alert for throttle oversteer as one accelerated out of the turn, Originally posted by jhigdon - Feb 14 2006 :  10:06:25 PM

throttle oversteer? whats that, lol. i only get understeer as i accelarate. jk

[AustinTX]

IMO, if you're not finding increasing radius turns on pretty much every course you run on, you may have been paying too much attention to the cones.  Interpretation of the space between the cones is where you make up time.  The difference may just be that it doesn't require a bunch of cones to describe an increasing radius turn, since it would only be describing the arc you should be taking anyway in an accelleration zone.

[jhigdon]

Rich and AustinTX, I do agree with you that many of the turns on sundays course could indeed be taken with an increasing radius. Many of the harder turns on the course where taken as increasing radius because we could not brake in a turn (too much lockup) and where forced to brake early and hard. What I thinking of is a very pronounced increasing radius turn, more or less a whole section of a course designed around this turn to have high speed in and need high speed out. Its just an idea I've had, as you know Rich we end up designing a lot of courses over at UTSA and we try something different everytime, and the one or two times we've had turns with a pronounced increasing radius it has added an extra degree of difficulty to the course, just an idea.

[Shortcutsleeping]

Every Costas-Cross at TAMU has 1 very well marked DEcreasing radius turn and 1 very well marked INcreasing radius turns. I love watching how folks take them throughout the day.

Usually ax # 3 of each semester.

Costas

[red84vette]

1. From R Johnson's notes and thus SCCA just remember that an increasing radius turn, if it does not require a lot of effort, could be classified as a straight, so when making a big sweeper into a fast portion, you'll want to think about speeds into the next maneuver.  We all will love the speed, but there are safety guidelines.  The membership will ask for something just below Ludicrous Speed, the SCCA will say something around 60MPH, and the Insurance Company will ask for something in the single-digits.  I think the "trick" is to make the increase just gradual enough have some fun.  Maybe even at the start, where you HAVE to be a zero MPH.

2.  We had a quick discussion around someone's course with a "cinnamon swirl" that had just such a maneuver, and it looks like it would take up a lot of space on the lot.

3. I noticed that if I stomp on the gas in my car, and it hooks up, all turns become "increasing radius....."  no matter how the cones are laid out.

[miata_racer]

Personally all I try to do on my courses is look for flow and safety.

First thing I design is the stop box. I always try to have adequate stopping distance for certain speeds. Then I design the previous manuver so as not to encourage spinning through the finish.

Then I think of elements I want in the course and place them accordingly. Then connect them with other manuvers or not so much in a way that the course isn't painful, and flows well but not in a way that you're always back and fourth on the wheel. (not sure that made sense out loud).

I also try to make them easy to get through, but rewarding the faster or more skilled driver who chooses a good line and punishes them in some areas a little for being off. Also, I like to have some sections that can be taken 2-3 different ways so as to allow variation in lines between drivers.

As for the orginal question about increasing radius.....an increasing slalom is a series of increasing radius turns sort of....and an increasing radius sweeper isn't a bad thing. But as stated about....take note of entry speed and exit speed.

If you want to acheive a 45mph exit speed, I would make it a very slight increasing radius turn so that the entry speed won't have to be below 20mph.

I also try to avoid (I never do this actually) designing any course that uses first gear. Most folks hate it, and it's just one more thing that will piss off and confuse newbies. 100 things to think about on a run is enough (it was for me at least). :-)

David