Rail Riding - "How To Guide"

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.

Have you had success with a "rail rider"?

Yes
90
49%
No
8
4%
Somewhat
12
7%
Haven't tried yet
72
40%
 
Total votes: 182

HERBIE
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Re: Rail Riding - "How To Guide"

Post by HERBIE » Sat Mar 15, 2008 12:10 pm

Thanks for the input, So we still have the weight shifted to the front RR tire and the non RR tire is still in contact just rolling along? Before on the 3 wheel setup, we were just narrowed the front end on the RR wheel side. Is this the same for 4 wheel or would you bring both front wheels in? Again, thanks for the info :)



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Stan Pope
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Re: Rail Riding - "How To Guide"

Post by Stan Pope » Sat Mar 15, 2008 1:52 pm

Narrowing opposite from the RR wheel is a tough call. Stanley did not, but I can see that the "free-rolling wheel" might keep a straighter course if he had. On the other hand, a small bump of the RR wheel off the rail increases the probability that the 4th wheel rubs the rail hard. Note that Doc Jobe's tests say to narrow them both on a 4-wheeler.


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Go Bubba Go
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Re: Rail Riding - "How To Guide"

Post by Go Bubba Go » Sat Mar 15, 2008 2:32 pm

Stan Pope wrote:Narrowing opposite from the RR wheel is a tough call. Stanley did not, but I can see that the "free-rolling wheel" might keep a straighter course if he had. On the other hand, a small bump of the RR wheel off the rail increases the probability that the 4th wheel rubs the rail hard. Note that Doc Jobe's tests say to narrow them both on a 4-wheeler.
FWIW we narrow both front sides, for a slightly different reason. Our cars are thin enough that we have experienced some issues with the car body twisting a little as the paint, clear coat, etc. dries, lifting one side or the other slightly in the front. The amount of twist / lift is typically not enough to raise a wheel off the track and violate our 4 wheels touching rule (sometimes it is... :(, but not usually), but if it is in the right direction it can easily be enough to change which wheel is dominant.

If we only narrowed one side, and after the painting, clear coat, etc. twist was all done the other side was now dominant, it would complicate things a bit. To avoid this complication we finish all the body and paint work, let it dry thoroughly, and then insert the wheels and axles and determine which front wheel is dominant after the "body twisting" is done. With both front sides narrowed slightly, we are then set up to RR on either side based on which front wheel remains dominant in the end.

So far we haven't seen any ill effects from narrowing both sides, but we do know a neighborhood guy who narrowed a little too much on both sides and started to see slowdown. :(

Bubba


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Stan Pope
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Re: Rail Riding - "How To Guide"

Post by Stan Pope » Sat Mar 15, 2008 3:19 pm

Great point!

If you put your car on 4 even scale pans, what does the scale under the "other" front wheel read?


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Go Bubba Go
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Re: Rail Riding - "How To Guide"

Post by Go Bubba Go » Sat Mar 15, 2008 3:32 pm

Stan Pope wrote:Great point!

If you put your car on 4 even scale pans, what does the scale under the "other" front wheel read?
I take it your question is to Herbie?

As for us, we never tried it (yet)!

First I'd need 3 more scales... may be time for another Harbor Freight run! (although they were cleaned out of the $9.99 pocket model when I went on Thursday).

It would be interesting to measure and see the performance of the different "4 wheel touching" scenarios below:

1) Weight equally distributed between front wheels.
2) Weight present on non-dominant, but less than on dominant.
3) No weight on non-dominant (i.e. axle riding inside bore, but not touching - wheel sort of rolling along for the ride)
4) Axle rubbing the top of the bore slightly / slightly lifting the non-dominant.

Might have to work on that for next year's fleet.

Bubba


"Who's Grandpa's neighbor?"... Phil Davis, Down and Derby

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Re: Rail Riding - "How To Guide"

Post by HERBIE » Sat Mar 15, 2008 4:14 pm

That’s could question Stan, we could calibrate a simple spring and pointer set-up on each tire for some rough measurements. We only have the one scale and we don’t have any individual load cells to put under each tire. Finding out about the rules to late in the game probably won’t leave much time for testing but thankfully we can make an educated guess by reading the comments on Derby talk.

Bubba, I like what your thinking with the lifted side after painting and we have looked at that as an option. We are debating a “C” shape car design for both cars instead of the usually false body panel on the side opposite the RR wheel. If they use the bottom of the car as a datum line for the measurements than your method would be a good choice. We didn’t see anyone with a ruler or calibers last year so our idea was a simple drill fixture on top of the granite surface to locate the axle in the center of the wheel and hoping no one has developed calibrated eye.

Thanks Again



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Re: Rail Riding - "How To Guide"

Post by Stan Pope » Sat Mar 15, 2008 5:44 pm

They don't say that the 4th wheel needs to bear any weight, only that it need to touch the track. That means (to me) the rule requires that when the car moves, the wheel will roll. The rule says noting about bearing any of the car's weight. :)


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Go Bubba Go
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Re: Rail Riding - "How To Guide"

Post by Go Bubba Go » Sat Mar 15, 2008 5:52 pm

Stan Pope wrote:They don't say that the 4th wheel needs to bear any weight, only that it need to touch the track. That means (to me) the rule requires that when the car moves, the wheel will roll. The rule says noting about bearing any of the car's weight. :)
That is basically what our rule says - the 4 wheels need to touch the track and the entire tread surface needs to touch the track.

We check this by 2 roll tests. The first one you're looking to ensure all 4 are rolling. The second one your looking to ensure all 4 touch the entire tread width. Tougher to do both at the same time than you might think.

We do not stipulate or check that both front wheels bear weight. THANK GOODNESS!!! It's tough enough for your average (even experienced) Cub (and parent) to get them all touching and flat.

Bubba


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Re: Rail Riding - "How To Guide"

Post by pinecarpro » Sat Mar 15, 2008 10:34 pm

Bubba wrote:

Our rules say - the 4 wheels need to touch the track and the entire tread surface needs to touch the track. :shock:

THANK GOODNESS!!! It's tough enough for your average (even experienced) Cub (and parent) to get them all touching and flat.

How do people come to these RULES!!!! If a 6 year old can not meet a rule then it is REDICULIOUS!!!!! :wall:

I think your pack should add if a car touches the rail on the way down the track it is disqualified. :x

Pinecar
PS I think we agree



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Re: Rail Riding - "How To Guide"

Post by 3 Cub Dad » Sat Mar 15, 2008 10:45 pm

pinecarpro wrote:Bubba wrote:

Our rules say - the 4 wheels need to touch the track and the entire tread surface needs to touch the track. :shock:

THANK GOODNESS!!! It's tough enough for your average (even experienced) Cub (and parent) to get them all touching and flat.

How do people come to these RULES!!!! If a 6 year old can not meet a rule then it is REDICULIOUS!!!!! :wall:

I think your pack should add if a car touches the rail on the way down the track it is disqualified. :x

Pinecar
PS I think we agree
If I could add one thing.....

-stepping on soapbox-

AMEN!!!!!!!!!

-stepping off soapbox-



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Re: Rail Riding - "How To Guide"

Post by doct1010 » Sun Mar 16, 2008 8:22 am

pinecarpro wrote: I think your pack should add if a car touches the rail on the way down the track it is disqualified. :x
Coming soon to a district somewhere in Alabama. :D



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Re: Rail Riding - "How To Guide"

Post by Go Bubba Go » Mon Mar 17, 2008 7:41 am

3 Cub Dad wrote:
pinecarpro wrote:Bubba wrote:

Our rules say - the 4 wheels need to touch the track and the entire tread surface needs to touch the track. :shock:

THANK GOODNESS!!! It's tough enough for your average (even experienced) Cub (and parent) to get them all touching and flat.

How do people come to these RULES!!!! If a 6 year old can not meet a rule then it is REDICULIOUS!!!!! :wall:

I think your pack should add if a car touches the rail on the way down the track it is disqualified. :x

Pinecar
PS I think we agree
If I could add one thing.....

-stepping on soapbox-

AMEN!!!!!!!!!

-stepping off soapbox-
These are actually the Council rules, which we adopt at the Pack to ensure no (or fewer) issues when our boys participate in the Council event.

I joined the Council Pinewood Committee about a year and a half ago (went to ask some rule questions to ensure my workshops for the Pack were "on base" - next thing you know I'm overseeing a track area all weekend at the Council event :wink:) This rule is at the top of my list for changes I am hoping to persuade the Committee to adopt. A couple of obstacles right now:

1) Lots of other "big issues" right now with the Council event (loss of Sponsor, new location, poor volunteer support last year, etc...) are dominating the discourse.

2) The rules have been the rules for eons (your basic hesitancy to change issue)

3) I'm the Junior guy by about 8 years (we have one member who has been on since the event began 33 years ago) so I have a few more "dues to pay" before my arguments get a more unbiased hearing.

But I'm gonna plug away at it... wish me luck!

Bubba


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Re: Rail Riding - "How To Guide"

Post by woodworx » Mon Mar 17, 2008 6:51 pm

Im in Bubba's council, so GO BUBBA GO I say



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Re: Rail Riding - "How To Guide"

Post by HERBIE » Tue Mar 18, 2008 8:09 pm

As I told our district pinewood leader when asked me to suggest some rule changes to reduce the amount of illegal parts and ebay cars. "I didn't create this monster but like NASCAR I like a close race“. We run 10 -12 kids through our garage, building cars while trying to stay inside the rules. My suggestion was; one day, in one gym, all day and a strip search conducted on all the Dads as they enter the room. The only rules are the ones included in the box. The pack race would come at the end of the day and all the winners would meet later that night for the district. That’s the only way I know to level the playing field. Note: This is not a slam on anyone selling BSA approve parts and providing information to people who do not have the means to make competitive parts for building their own cars.



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