Axle feedback for this track?

[ugotkevin]

[video]https://www.youtube.com/watch?v=PzJEUALJIqg[/video]

So last night my daughter had her pinewood derby race (the white one). She didn't put much time or effort into her car (she didn't do anything to her wheels / axles), but that's her choice - she did have a great time though so that's all that really mattered! It was an extended wheelbase, 3* non-bent rears, the FDW was on the left (driver's) side. Alignment was about 1.5"/4'. COG was about 1" forward.

I didn't get a super close look at the track but as you can see from the video it's quite old. It seemed that the center rail is a bit wider, I'd guess about 1/4" wiggle room. Also the center rail seemed to be quite low, especially where the different sections of track are joined together. Hers wasn't the only car to be sliding around.

My son has his race the 3rd week of April. Right now his car is setup similar to his sister's except the FDW is on the right side. How would you guys setup your car for this track?

 

[ugotkevin]

I forgot to mention that her car was a 3 wheeled rail rider, the ndfw was raised 1/16".

 

[Crash Enburn]

In each case where it jumped the track, it jumped it toward the DFW. As though the DFW is pulling the nose of the car, instead of steering itself into the rail. Is that how you set it up? If so, steer the other direction.

Is your son going to be racing on the same track?

 

[Kinser Racing]

For the first time, I'm going to say that you need as little bend on the dominant axle as you can to still steer but keep the wheel as flat as you can. That rail is so short the wheel is grabbing it and steering right over it.

 

[ugotkevin]

Well I measured the alignment and it's 4" over 4' to the right. The raised wheel is quite high though. I couldn't find my ruler but I'm guessing somewhere around 1/8". I don't have a lot of experience with PWD but I'm guessing that either the track wasn't level and the raised wheel is too high so it jumped, the rear alignment might be off so it's somehow pushing the front out, or maybe too much wood was sanded off the DFW? I'm just trying to make sense of it all.

 

[Kinser Racing]

It looks like the rail is really short. Like an eight of an inch. I stand by my statement unless you can provide information that it's taller.

 

[ugotkevin]

It looked pretty short and was even shorter where the track came together. Besides getting the DFW as flat as possible how would you setup the rest of the car? Would you raise the NDFW? 3* rears? Would you move the CG up more?

 

[Crash Enburn]

*I* would lower the NDFW. Let it free-wheel, and set it so that it would steer the same direction as your DFW. That way, if it contacts the rail, or worse, jumps onto it again, it will help drive the DFW back where it wants to be.

I'd keep the CG where it is. Moving it back would likely exaggerate the problem by making the front end lighter.

So, your son is racing on this same track?

 

[ugotkevin]

Yep same track. I can see why they don't care much for rules now /images/boards/smilies/smile.gif

Right now his car is setup with the right being FDW, should we change it over to the left?

 

[Kinser Racing]

*I* would lower the NDFW. Let it free-wheel, and set it so that it would steer the same direction as your DFW. That way, if it contacts the rail, or worse, jumps onto it again, it will help drive the DFW back where it wants to be.

I'd keep the CG where it is. Moving it back would likely exaggerate the problem by making the front end lighter.

So, your son is racing on this same track?

The NDFW will be lowered just by decreasing the bend on the dominant axle. It may not clear, so check it. I'm not convinced on free wheeling it.