Would you build a rail-rider for a questionable track?

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Vitamin K
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Would you build a rail-rider for a questionable track?

Post by Vitamin K » Mon Jan 12, 2015 11:41 am

So, right on the heels of Pinewood Derby this year is the Awana Grand Prix, which my kids will need cars for.

Don't feel bad for me...it's an excuse for us to build more cars!

However, the Awana race standards seem /much/ looser than we approach things for the Pack Race. I intend to learn as much as I can, but I'm not certain I have a lot of confidence in how they run things. They mean well, but doing it right requires a degree of obsession that I don't detect.

So, here's the question: Should I help the kids build rail runner cars, if I'm not certain whether or not the people putting the track up know how to properly align it? Or should we just go with straight-runners? I would just hate to help my kid build a nicely aligned car, only to have it go airborne when the DFW hits a bad join.



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Re: Would you build a rail-rider for a questionable track?

Post by sporty » Mon Jan 12, 2015 12:17 pm

Rail rider..



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Re: Would you build a rail-rider for a questionable track?

Post by ngyoung » Mon Jan 12, 2015 12:59 pm

Rough or not the alternative is that it pin-balls down the track. Rail running will at least allow the car to run straight and re-set itself if it catches a seem that pulls it off the rail.



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Re: Would you build a rail-rider for a questionable track?

Post by LightninBoy » Mon Jan 12, 2015 1:00 pm

Yep, rail rider.

Track concerns just means maybe a little more weight on the DFW and a little more steer.



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Re: Would you build a rail-rider for a questionable track?

Post by Stan Pope » Mon Jan 12, 2015 2:49 pm

Toe-in keeps the DFW at (or close to) the rail and, together with correct rear alignment, keeps the rear wheels and lifted wheel off the rail.

Positive camber keeps the edge of the DFW from striking the top of a misaligned track section. If the wheel edge strikes the top of such a section, the front end lifts; if the wheel edge strikes the side of such a section, the front end gets knocked to the side and promptly steers the car back to its straight-line path!


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LightninBoy
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Re: Would you build a rail-rider for a questionable track?

Post by LightninBoy » Tue Jan 13, 2015 10:49 am

Stan Pope wrote:Toe-in keeps the DFW at (or close to) the rail and, together with correct rear alignment, keeps the rear wheels and lifted wheel off the rail.

Positive camber keeps the edge of the DFW from striking the top of a misaligned track section. If the wheel edge strikes the top of such a section, the front end lifts; if the wheel edge strikes the side of such a section, the front end gets knocked to the side and promptly steers the car back to its straight-line path!
Yeah - its good that you called out the positive camber here. I take that as a given now, but shouldn't assume it for others.



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Re: Would you build a rail-rider for a questionable track?

Post by Topspin.D » Tue Jan 13, 2015 12:35 pm

Rail runner. I would actually add a little more steer in this situation.



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Re: Would you build a rail-rider for a questionable track?

Post by FatSebastian » Sun Feb 22, 2015 4:07 pm

Topspin.D wrote:Rail runner. I would actually add a little more steer in this situation.
Interesting. I would have thought the opposite - less aggressive steer-in (and CoM placement) for a questionable track. The track we usually run on (a decades-old wooden track) would be by most people's standards today a questionable track.



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Re: Would you build a rail-rider for a questionable track?

Post by Speedster » Fri Feb 27, 2015 5:29 am

No one commented on FS's thoughts. I'm curious to know what others think.
I'd like to share our experience from a week ago. We raced on the worst 3 lane wood track I have ever seen in the past 30 years. The wood sections all sagged. Miraculously, only 2 cars flew off the track.
I don't know if there was a joint problem. Some of the cars wobbled horribly. I think the guide strip was 1 1/2" wide as opposed to 1 5/8". We had a 4 on the ground rail rider and I didn't see it jump so maybe the joints were fine or maybe the right side of the joints were fine. After tuning on my track and reaching its fastest time, the drift was 2" in 31". There was one other car that was just as fast as we were on the last run for the pack trophy. It was a sleek wedge with a nice paint job. Whether we were on the fast lane or a slow lane, I'll never know. We were called the winner. Thank Heaven for electronics. The Father of the owner of the sleek wedge was a nice guy but he wouldn't tell me NOTHIN'. Do you feel a 2" drift in 31" is aggressive?
Last edited by Speedster on Fri Feb 27, 2015 8:09 am, edited 1 time in total.



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Re: Would you build a rail-rider for a questionable track?

Post by Vitamin K » Fri Feb 27, 2015 6:32 am

FWIW, I don't consider an older wooden track to be automatically "questionable." The "Questionable" aspect comes into place when you have a track that is operated by people who don't know how to properly assemble/align it. When we put our Freedom track together for the first time, there was a good 1/8" misalignment in the guide strip between sections, and a test car that I rolled down it went airborne. What I'm wondering is how to handle situations like this, in which you suspect that the people who are running the race have no idea how to properly assemble the equipment. (Assuming that taking over track setup is not an option).



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Re: Would you build a rail-rider for a questionable track?

Post by Scrollsawer » Sat Jan 23, 2016 7:32 pm

Really timely post for us tonight! We had a Scouts' car set up to rail ride with the DFW on the left side of the car. In lane 3 tonight, the car jumped it's lane 3 times, likely due to the DFW wheel hitting a misaligned track joint, which I am sure cost the car it's tuning, and consequently several hundredth's of a second, which as you know is huge in PWD racing.

The track is definitely showing it's age, and while the Scout still won the Derby, it was with a car that was definitely knocked out of tune. The answer to the question is..."how can you tell if the track's bad (no touching before the race), and how would you know before you build begins?" Ergo, build a rail runner every time.

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