Jumping the track

[Noskills]

Hello gurus,
We had our first PWD last week and my sons car was average but it jumped the track twice and I dont know why. I suspect that it was placed at a slight angle in the gate as the front of my car was tapered and only about 1 inch wide. I think this as it jumped the track right out of the gate. I did a have 3 wheeled car and I was worried that the high wheel allowed it to jump-I think this is probably not the case as it was only 1/16 of an inch up and it would take a pretty good bump in the track to allow this to happen-right? I also know that it was not the center of gravity as the COG was suboptimal at about 1.5-2 in in front of the rear axel.
Any thoughts?
Thank you,

Noskills

[rpcarpe]

Any irregularities in the track? Other cars have problems at the same place?

[Noskills]

I didn't see any other cars jump the track with the exception of one that clearly was too back heavy. I wonder if the guy putting my car on the track was just a little off center on 2 occassions. The other runs it made were smooth.

[rpcarpe]

Could be, I've staged 100+ cars for racing.... not a job for the slippery of fingers.
Probably just a bad staging for your car. We now teach the kids to stage their own cars, properly.

[Stan Pope]

...
We now teach the kids to stage their own cars, properly.

[Noskills]

I am guessing that it best to have the front of the car not taper. Yet if making a wedge how thick should the leading edge be? 1/4 in?

Would it be helpful to put a slight depression in the very center of the leading edge so the the stager naturally slides it in well centered? I bet midline pinstriping would help this too.

[rpcarpe]

Many people recommend putting a stripe, or some design feature to help stage the car properly.

Most folks in my workshop take the nose down to an airplane type taper, or they go knife-edge.
About 1/4" of thickness where the axles go should suffice, you can get by with less.

[Noskills]

After learning a ton these last three week I realized that my car may have had a two inch draift towards my elevated front wheel. Might that facilitate track jumping?
Noskills

[gpraceman]

After learning a ton these last three week I realized that my car may have had a two inch draift towards my elevated front wheel. Might that facilitate track jumping?
Noskills

Most definitely. The drift should be towards the front wheel that is contacting the track, called the Dominant Front Wheel (DFW). If your raised wheel is hitting the guide strip, then that might be just enough to get the wheel to pop up onto the guide strip, leading to a derailment.

[Noskills]

Thanks gpraceman,
Before DT I know just enough to be dangerous. I bought a block predrilled as 3 wheeler as this made good sense to me. I saw the youtube video about rail riding but I did not understand it; my take home point was that some drift was good. I tested my car for a straight run as per the Meade book. When I saw a little drift, I was too lazy to correct it and thought that maybe I would get the RR effect I saw on youtube. Concepts like the DFW, toe-in and camber were not available to me. The direction of the drift was also lost to me.

I feel much better knowing the cause now (which may also have been due to poor staging. I still feel sick when I recall seeing my son's car derail once to the inside of the track and once off the track (where it broke a little). Both times it was on the side of the DFW.

Noskill

[FatSebastian]

I realized that my car may have had a two inch drift towards my elevated front wheel. Might that facilitate track jumping?

Most definitely. The drift should be towards the front wheel that is contacting the track, called the Dominant Front Wheel (DFW).

I was confused by the description. If the car drifts (steers) toward the elevated wheel, to me that implies that the elevated wheel was headed away from the center rail!

[Noskills]

FS,
You are right. The car drifted away from the elevated wheel.
My elevated wheel was on the left. Each time the car jumped the track it did so by steering to the right.
So when in the far left lane it jumped into the center lane, and when in the far right lane is leap over the edge.
I initially thought this may have been due to being top heavy due to the plastic cockpit, but my weight was very low in the car and the pastic is pretty light. I ruled this out as a cause.
Noskills

[gpraceman]

FS,
You are right. The car drifted away from the elevated wheel.

I guess that you've got me confused as well. Was the raised wheel drifting towards the guide rail or away from it? I initially thought that you meant it was drifting towards the rail.

[Noskills]

Yes, the raised wheel was drifting to the center guiderail.

[resullivan]

The wheel that is not raised is the one that should drift and eventually stay on the guide rail. I am no RR expert, but I think one of the main points of RR is to keep the raised wheel off of the guiderail. Point being that the raised wheel is not spinning so when it makes contact it absorbs more energy (AKA slow your car down) than a spinning wheel.