School of R/C #1: The Racing Line

At our practice session last night, we kicked off what will hopefully be a semi-regular “School of R/C”.  This is all about helping you go faster, get more performance from your car, improve your driving and preparation.  If there are topics you’d like to see addressed in future “School” sessions, let us know.

To go fast in R/C racing, there are four simple tasks:

  1. Know the quickest way around the track
  2. Have the driving skills to get your car onto the racing line you’ve figure out in (1)
  3. Setting up your car so that it’s capable of delivering fast times, and works in the way you need it to with your driving style.
  4. Doing all of the above in traffic!

Today’s session concentrated on the first task – knowing the quickest way around the track.

The Racing Line

Put simply, the racing line is the line your car will follow around the track that generates the fastest lap times.

In any given corner, following a line that gives the widest radius will help you carry the most speed through the corner. It’s a simple formula of traction vs centrifugal force.  Traction is roughly constant, so the tighter the corner, the slower the speed you can carry.  The objective is, in any given corner, to drive the “straightest” line possible – the widest arc, and carry the highest speed.

Read this Wikipedia article on finding the best racing line through a given corner.

Or watch this video….it’s excellent:

The Problem?

So, we’ve figured out the fastest way through a corner.  Problem solved?

Not quite.

There are two major issues to be resolved. The first is variation in the track condition.  Some parts of the track might carry dust and dirt, so produce less traction – so the racing line has to be modified to allow for it.  At Launceston R/C we have some parts of the track that gather more dust – so the ideal racing line avoids them.  It might mean entering a corner earlier, or staying tighter on exit, or sometimes avoiding the apex of a corner.

The bigger problem however, is the next corner.  There is no use driving the “perfect” line through a hairpin right-hander if it’s immediately followed by a hairpin left….and we’re left in the wrong place on the track.

So the racing line becomes an art of compromise – carrying as much speed through a corner, holding a line that enables the earliest application of throttle, but making sure that the outcome leaves us well positioned for the next corner.

Mapping the Track

It’s not only important to figure out the line you want to follow through one corner, but it’s important to figure it out for the whole track….and to take the track as a whole.  What you do in turn one, will shape what you can do in turns two and three.

When I visit a new track, often before I drive a car, I’ll walk around the track, looking closely at it.  I’m looking at the surface, the shapes of the corners, the positioning and shapes of jumps, areas where traction might be lower, or higher than average.

Then I’ll sit down with a sheet of paper, and map the track.  Onto my map I’ll draw in my ideal racing line, taking into account all those factors – corner shape, traction, bumps, jumps, areas where traffic might be an issue.  I’ll make lots of notes on my map about where I want my car to be, when I want to be on the throttle or brakes, whether I want my car to be sliding (rare) or driving it straight and smooth (most of the time). I’ll mark potential trouble spots, make notes about where I want to hit jumps.

When I’m happy that I know exactly where I want my car to be at any given point on the track, I’ll go run some laps.

And I’ll learn some things.

The lines I had hoped for weren’t possible because I misread the traction, or missed noting a big bump, or my car can’t handle the jumps the way I’d like it to.  Or maybe I’m just not quite able to put the car where I want it.

Then I’ll go to work.

First I’ll re-work my map – making new notes about the track conditions, and again being sure that I know exactly where I want my car to be.

Then I’ll work on the car – adjusting suspension, tyres, chassis so that it can deliver the lines I want, with the skills I have available.

And then I’ll practice….bringing my skills up to speed on the track.

All of that starts with understanding exactly where I want my car to be.  And why does that matter so much?  Because if my car is exactly where I want it to be on any given part of the track, not only will I never crash (because my ideal line doesn’t intersect with any corner barriers), but I’ll win more races than I’ll lose because my lap times will be fast and consistent…..and that’s my objective.

So…..first understand exactly where you want your car to be.  Then go to work on your driving skills so you can put it there, your tuning skills so you can make it do what it needs to do…..and then later we’ll deal with traffic!

Before Next Time

Draw your own map of the racetrack at Launceston R/C.  Seriously. Get a piece of paper, and a pencil and draw it up. Mark in the bumps and jumps, the slippery spots where dust collects. Draw in your racing line, and make notes about what you want to be happening in any given part of the track.  Where are you accelerating? Where are you braking? Where are your turn-in points?  How far to do you want to stay in the air over each of the jumps?  Where is the dirt and dust you want to avoid?

And the night before our next race meeting, study your map. Go over it again, and again and again. Rehearse your racing line in your mind.

And on race night…..be disciplined. If your car isn’t on the line you want it to be, get out of the throttle, steer your car back to your chosen racing line….and stick with it!  If you study your map hard enough, you might even be able to imagine a chalk line on the track – the line you want to follow.

Next time…..Driving Skills 101.

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About scottg

Scott Guyatt is husband, father, brother, son, friend, disciple, runner, cyclist and story-teller
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21 Responses to School of R/C #1: The Racing Line

  1. Dave says:

    Wow-wee Scott.
    What an inspiring write up.
    I was not happy at having to miss Thursday night because I knew you have so much to pass on.
    Thanks for sharing and providing such invaluable knowledge on the art of racing.
    I would love to see what you achieve behind a 1:1 scale 😉

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  3. Corey says:

    Great write up Scott, wish i could have made it Thursday night. Guys i have an issue with me slash, it has a Novak 3S ballistic system in it – running a 7-cell 8.4volt nihm battery. It goes fine then all of sudden no acceleration, but obviously there is still power as steering works. I though it may have been the senor wire on my esc or novak motor might be not quite connected properly, but no it wasn’t that. I turn it off and back on again and its fine, it all works ok again but then i drive up the road and back about 100meters each ways and then it starts doing it again. DOES this sound like its over-heating to you guys??? The motor feels warm but not excessively hot or anything.
    Thanks

    Corey

  4. Greenie says:

    can you hold the motor for over 3 seconds with out burning yourself?? (ok way to tell if its too hot.)

    the esc might be set to LiPo’s, so when the Volts drop, the esc is cutting the motor out. (does this to save the LiPo’s) but not need with a NiMh

    might be wrong but someone will put me right!!!

    • Greenie says:

      oh, your gear mesh might be to tight, or something is binding out somewhere in the drive line wich would/could cause it to overheat and Thermal out.

      • scottg says:

        low voltage cutout sounds like it could be the culprit. I’m not familiar with settings on the Novak ballistic, but if it’s on “auto” it could be detecting the 7-cell pack as a 3s LiPo – and then it would cut out at 9 volts – something like what you’ve described.

        If you have the option in the ESC settings, turn the low voltage cutout “off” or to “NiMh” while you’re using your nimh batts. You only need it on if you’re running LiPo packs.

      • Greenie says:

        i think they have an “off” option, settings for 1,2,3 cells and off.

  5. Corey says:

    Thanks guys, i will check it out. Hey i also should have noted that i recently changed the gearing, i changed it to 23pinion and 86spur, but i tested it for about 30mins and gave it a real bashing and keep checking temps and they were no where near burning you like Greenie said. I have the lipo cutout on my little erevo and if its turned on for that it willnt start with a Nihm battery installed in it – but i think i did read that the Novak 3S ESC auto detects the battery type, anyhow thanks for advice and will check it out and lets ya know what it was
    Cheers

    Corey

  6. Greenie says:

    the auto i think is only for the LiPo’s as it detects the number of cells, not for the old school NiMh’s

  7. Paddy says:

    Novak’s come new with auto lipo on. If you got it new and haven’t touched it, its definitely the culprit. And yeah it will work in lipo mode with Nimh’s…

  8. Corey says:

    thanks fella’s

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