20' Test Track

Discussions on buying, building or rehabbing a race track. Topics like plans, materials, tools, construction, finishing, commercially available tracks, and so on.
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Gauge
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20' Test Track

Post by Gauge » Mon Apr 07, 2008 12:33 pm

Does anyone own the 20', single lane, best track, test track? I am thinking about buying one but have a few questions.
Since it is only 2' tall, can it accurately represent a cars performance on a full size track.
Would it more accurately represent a 35' or 42' track?
Would it accurately represent a cars performance on the flat?
Any feedback would be greatly appreciated. I have had a couple people tell me they like theirs but I am wanting to hear the pros and cons.

—Gauge



Teeeman
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Re: 20' Test Track

Post by Teeeman » Mon Apr 07, 2008 3:20 pm

We have a 15' homemade track for testing...

our experiences on this track:

1) it is smoother than most wooden tracks

2) cars with aggressive COMs but the dreaded wiggle problem do well on this track as there is only 8 feet of flat straight... this is bad as it masks how much ground a wiggling car will lose on a track with a long straight

3) it is a good "wiggle meter" as it allows us to see wiggle form, we (by dumb luck) made the 3 lane joints such that one is rough, one is medium and one is fairly smooth (go figure, I'll take that kind of luck anyday, hahahah!)

4) it is just a lot of fun to play with (it works with K-Nex car, hot wheels and stuffed animals too!)

:)


-Terry


"I dunno..." - Uncle Eddie, Christmas Vacation

quadad
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Re: 20' Test Track

Post by quadad » Wed Apr 09, 2008 9:23 am

Sorry I don't have experience with this track or any scaled tracks, I can only explain how I approached the same need. My choice was to build a test track that closely resembled the lengths, slopes, etc. of the track our pack uses. I made it 3-lane (using inexpensive smooth paneling as the riding surface and ripped 1/4" plywood for the lane guides) since the material list was pretty much similar to a one-lane and we have three scouts at home.

It was successful in that it gives us a pretty good indication of how our cars will perform at the pack level, obviously anything could be different at council/district level. The biggest expense was the timer (MicroWizard), but pretty important I think. The down side was that even with copying existing plans, it took me parts of three weekends to build it. (Built when we should have been working on our cars ! :roll: )

So my point is you have to know something about what track you are going to compete on to judge how good an indicator this track will be. I am sure it will be measurably better than just an 8' test board. I think Teeeman's experience is worth noting. We have only run long wheelbase, non RR cars that are pretty stable so far, so I don't have that kind of experience to relate.



Hurly64
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Re: 20' Test Track

Post by Hurly64 » Wed Mar 11, 2009 10:16 pm

I know this is an old topic, but I'll put in my 2cents anyway. Testing a car at a slower speed that a 2 foot height offers is actually much more informative than testing at full speed, as it allows one to see exactly what the car is doing. Is it riding the rail consistently? Is it banging the rail, drifting away, and then banging the rail again? Are all wheels making contact with the track surface? All these behaviors are much more evident and easier to see at half speed or even less. Why give yourself only 3 seconds to analyze a blur when you can give yourself 6 or 7 seconds to analyze the alignment of the whole car.



priority
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Re: 20' Test Track

Post by priority » Tue Mar 02, 2010 1:54 pm

Needed a break from other stuff and stumbled across this thread.

The physics of the 20' best track are not exactly what I thought would happen before I actually experienced it. First, the run time of a well tuned car is just over 2 seconds on this track. Second, it is very difficult to translate the performance of a car on a this track to a 35' or 42' best track. For example, how does a 5msec difference between two cars on the 20' track translate to a 42' track? This is not a linear extrapolation you can do easily, but Doc Jobe's software can help. Accurately predicting the perfomance on a Piantedosi is even harder. I found predicting the wiggles (at full speed on a full size track) is very hard to do (on a scaled down track) unless a car is just really bad in the rear end.

Even with these caveats, you can do a lot to tune a car on a scaled down track. Just be careful how far you extrapolate.



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