Testing your car on a guided track,when racing on a lane track

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Speedster
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Re: Testing your car on a guided track,when racing on a lane track

Post by Speedster » Wed Apr 11, 2018 9:39 am

Think hard. Your goal is to decrease Friction. Setting up a basic rail rider, only the very bottom inside of the Dfw (dominant front wheel) ever touches the guide strip. One front wheel is raised to save "Rotational Energy". If the car is set up to run the raised wheel into the side rail you have increased Friction a lot. If you set the car up to run the Dfw against the side rail no more then what is absolutely necessary, that's the only wheel that will have friction by touching the guide, whether it is a guide strip or a side rail. You can set your dfw with 1 1/2 degree Negative camber and a little toe out and it will migrate to the side rail. It's not going to take much to take it to the rail. Other cars will probably also go to the rail but they're going to end up having both side wheels into the rail. They might even bounce back and forth. Your car should run very straight.

Building 2 different cars is not going to give you the answer you want. There will be too many variables. You must do exactly every operation perfectly following science.

Don't ever worry about challenging my experience. Unfortunately, you'll need to get in line. That made you smile, didn't it.
I'm on your side. I wish you the best.
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Re: Testing your car on a guided track,when racing on a lane track

Post by Vitamin K » Wed Apr 11, 2018 10:21 am

MJThurston wrote:
Wed Apr 11, 2018 5:31 am

Thank you for the advice.

You have way more experience than I do on this. I'm going to say some things about what I have read. By no means take this as challenging your experience. I'll tell you what I've read and you can tell me if that is right or wrong. Again, please don't take this as me saying your wrong. I know how things can be read online.

One front wheel up. One front wheel at 1.5 negative. Both back wheels 2.5 positive. Car is to steer into the wall so the non moving wheel touching the side. This allows all the moving wheels to continue spinning.

You suggest have the front driving wheel touch the side and allow for the back wheels to not touch the side also.

I have two cars. One for my boyscout and one for his younger brother. I could set his younger brothers up as you suggest and test them both to see what happens.


Thank you.
I guess it's a little bit of a guessing game.

My preference is for a greater amount of camber on the front wheel, because it has to contact two surfaces: the track and the sidewall. I ideally want the contact of both to be on the edge of the wheel, because I want to achieve rolling friction on both.

Regarding the rears, I'm not certain I'd put positive camber on them. In my mind, positive is less desirable, because it causes the wheels to migrate in to the body of the car. My hunch is that riding on the axle heads is preferable. The insetting of the rear behind the dominant-front is the compensate for the rear potentially getting near the sidewall.

If you are going to build a few configurations, I would definitely build the tuning board with sidewalls and test them at slow speeds to watch the cars' behavior.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 10:32 am

Here is a pic of how the wheels of my car are set up.

https://goo.gl/images/W9c3hF



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Re: Testing your car on a guided track,when racing on a lane track

Post by Vitamin K » Wed Apr 11, 2018 10:38 am

MJThurston wrote:
Wed Apr 11, 2018 10:32 am
Here is a pic of how the wheels of my car are set up.

https://goo.gl/images/W9c3hF
That pic shows positive camber on the DFW. If you're running a sidewalls track, I think you'd be better off with negative.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 10:59 am

Ok.

My NDFW is raised.


I did get the single 32 foot track from derby magic. I will post something about it. It should be at my house when I get home.

Storage and price is why I went with it. The timer and program is a steal when it comes included. ( Wish I would have found this group befire a bought it. )



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Re: Testing your car on a guided track,when racing on a lane track

Post by Vitamin K » Wed Apr 11, 2018 11:52 am

MJThurston wrote:
Wed Apr 11, 2018 10:59 am
Ok.

My NDFW is raised.


I did get the single 32 foot track from derby magic. I will post something about it. It should be at my house when I get home.

Storage and price is why I went with it. The timer and program is a steal when it comes included. ( Wish I would have found this group befire a bought it. )
Sounds nice! Just remember that the Derby Magic track is center-guided, which would require a different rail-riding setup than the side-guided track you're trying to tune for.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 12:51 pm

Correct, my first idea is to get some thin ply wood and use if that can be attacked to the frame.



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Re: Testing your car on a guided track,when racing on a lane track

Post by Vitamin K » Wed Apr 11, 2018 1:28 pm

MJThurston wrote:
Wed Apr 11, 2018 12:51 pm
Correct, my first idea is to get some thin ply wood and use if that can be attacked to the frame.
Along all 32 feet???

That sounds like quite the project.

Honestly, just build a tuning board and go with that.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 3:01 pm

I'm putting the starting area together and the plastic piece that holds the starting mechanism was drilled incorrectly.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 3:51 pm

Had to re drill the holes to make it work and had to move a piece forward. Also a pin was stopping the starting pole that holds the car from going under the track. I had to modify the plastic piece to get clearance for that pin.

Basically the starter pole releases but the car would roll over the pole on the way down. It works fine now that I modified the plastic board.



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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Wed Apr 11, 2018 6:01 pm

The track is together.

1. Plastic board that is used for the start gate was not drilled correctly. Easily fixed but as someone that uses a Bridgeport there is no excuse for it not lining up. Also had to make clearance for a pin used for the switch. It was catching the board and not letting the starting pole to go below the track correctly.

2. Glue used to hold the joined sections is on the track. Not something that should be happening.

3. Timer works great but the way it attaches to the track could be better.

4. I think a board needs to be added to the bottom of the track to keep the track level.

5. Tested two cars. They both go back and forth down the track. Not something I want to happen.



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Re: Testing your car on a guided track,when racing on a lane track

Post by Speedster » Fri Apr 13, 2018 4:40 am

Regarding #5. I suspect the back wheels are causing this if you still have them set with Positive camber. Let's back up for a minute.
Take the front wheels off one of the cars. Set the back wheels with the 2 1/2 degrees of Negative camber. I'm going to assume you got the 2 1/2 degrees by bending the nails. Find a very smooth, level surface, (the kitchen table) hold the car parallel to the surface, pull it slowly forward and then backwards. Do both wheels stay on the axle heads? If not, adjust the nails until they do. Put the front wheels back on and leave the Dfw with the same Negative camber and toe in. What happens when you run it down the track? If it runs straight, this is the way I would run it down the other track but change the front wheel setting with toe-out. Do what is necessary to keep that rear wheel off the side strip. It has been suggested to narrow the car at that rear wheel and that sounds like a good idea.



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Re: Testing your car on a guided track,when racing on a lane track

Post by Loud2ns » Fri Apr 13, 2018 7:59 am

\----/
positive camber



/----\
Negative camber



Front toe in looking down on car


Dfw. /----| lifted wheel


Front toe out looking down on car


Dfw. \----| lifted wheel




Speedster- all that you have said is exactly how I would start to experiment




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Re: Testing your car on a guided track,when racing on a lane track

Post by MJThurston » Fri Apr 13, 2018 8:22 am

My car as of right now is as follows.

Back /----\
Front. Raised [---/ FEW

But I need to make sure I have the back wheels straight up and not left or right of center. Meaning the bend should be at 12 oclock and not at 11 or 1.



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Re: Testing your car on a guided track,when racing on a lane track

Post by Speedster » Fri Apr 13, 2018 1:20 pm

MJ, that is correct. If the nail is off the tiniest bit the wheel is going to have toe in or out. That's not desirable. However, when you're moving to the other track, if you're guiding the car to the right, the right rear wheel must not touch the right side guide. Narrowing the right rear side of the car would be one thing to try. Putting very slight toe out on the left rear wheel might be another thing to try. The toe out on the left rear wheel will pull the rear to the left which should keep the right rear wheel from touching the guide. This is going to be a guess in the speed without a track and timer. You'll find out what happens in the race.
The track with no center guide has so many variables. If you set up a straight runner the car might travel a great distance without touching anything. That might be very hard to beat. I have a feeling you're going to teach us all something.



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