Have you seen issues with fixed axle location rules?

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pwrd by tungsten
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Have you seen issues with fixed axle location rules?

Post by pwrd by tungsten » Wed Feb 05, 2014 3:17 am

Have you seen issues with fixed axle location rules (Drilling holes allowed)? Cars that show up with extended wheelbase and or rear axles back too far? Seems like a headache at check in and also a bummer to DQ cars.


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Re: Have you seen issues with fixed axle location rules?

Post by Speedster » Wed Feb 05, 2014 8:43 am

I've never had a problem with any of the 3 Packs I inspect. We don't allow drilled holes. Slots and axles must be visible. Stock wheelbase. I'm the only one that cuts the 1/4" off the back and moves it to the front. We have no rules that prohibits that. Folks in these Packs are not competitive for the most part even though we will be doing 5 workshops this year. We do not allow a car to race if it does not cross the finish line in a test run. Fortunately, we were able to get all cars to cross the Finish Line this year.



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Re: Have you seen issues with fixed axle location rules?

Post by macd » Wed Feb 05, 2014 10:30 pm

What are your rules?
Do they require, or imply the requirement, that every car be exactly 7 inches long?



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Re: Have you seen issues with fixed axle location rules?

Post by Speedster » Thu Feb 06, 2014 6:26 am

The car can be any length just not over 7". The unnecessary wood behind the rear wheels is moved to the front to take advantage of the "Front End Extension Effect". Shifting the wheelbase moves the CM higher up the arc.



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Re: Have you seen issues with fixed axle location rules?

Post by SlartyBartFast » Thu Feb 06, 2014 10:04 am

Speedster wrote:The car can be any length just not over 7". The unnecessary wood behind the rear wheels is moved to the front to take advantage of the "Front End Extension Effect". Shifting the wheelbase moves the CM higher up the arc.
Always struck me as odd that maximum nose and tail length from the axles aren't part of the rules. If the dimensioning is to ensure track clearance, need to make sure that the nose doesn't dig in and the tail doesn't drag.



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Re: Have you seen issues with fixed axle location rules?

Post by Speedster » Thu Feb 06, 2014 11:11 am

I'm not sure why the wheelbase isn't centered on the block. Perhaps the originators of the BSA block felt using the short end for the front made it look more like a real car. Pictures on the box has for years shown the car with the short end for the front. The most a scout can move the wood for benefit is 1/4". This brings the block even with the back of the rear wheels. This is the common position for the rear on extended wheelbase cars. Our Pack races on a wood circular arc track and the nose clears the guide strip easily. Our District races are held on a "Best" track and a Freedom track. These two tracks have no center section on the guide strip. Even if the car had a chance of scraping on the "Best" track, the front of the car could be designed to ride the center of the guide or even taper the front of the car.
There are some Districts who have a rule that would keep a scout from doing this. There are also some persons on DT ( ????) who would like to have this rule.



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Re: Have you seen issues with fixed axle location rules?

Post by Shawn Stebleton » Thu Feb 06, 2014 11:25 am

SlartyBartFast wrote:Always struck me as odd that maximum nose and tail length from the axles aren't part of the rules. If the dimensioning is to ensure track clearance, need to make sure that the nose doesn't dig in and the tail doesn't drag.
The district my boys have raced in only require slots (they check for solid axles) but allow the back to be cut off and front extended. We've never had a problem with the front digging in. We don't have anything below the bottom of the base plank. We were worried about that and had tapered the underside up in front, but found that was totally unnecessary, even on the old 2' radius Best Track curve.

If you were to shorten the wheelbase from the standard slot size and still have the rear axle back as far as possible, then I can see where you would start to have a problem.

Basically, if you have a 3/4" minimum clearance and have to use standard wheelbase, then you won't have an issue with the front end digging in, even on the tightest curve out there.


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Re: Have you seen issues with fixed axle location rules?

Post by Rfieldbuilds » Mon Feb 17, 2014 8:45 am

Check this post out for the expected head and heart ache of exactly what it is you ask about..

http://www.derbytalk.com/viewtopic.php?f=25&t=7498" target="_blank

Major headache for leaders and heartache for one father/son. I still advocate for fixed wheelbase to keep the field of play more uniform. Not every scout/dad has access to a decent drill press.



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Re: Have you seen issues with fixed axle location rules?

Post by birddog » Mon Feb 17, 2014 11:09 am

Our Pack rules use our District rules (copied straight from that source), so that any boys that go on to districts will have a car that meets those rules.

The district rules allow drilling of axle holes and specifically state that the wheel base must be between 4 3/8" and 4 5/8" long.

At our pack races, I've never had a car show up that violated that rule yet.

I'm told there are cars at the district race who show up with wheel bases longer than 4 5/8" and they end up getting DQ'd as a result. Given I'm running the district race this year, I'll have more experience to share once our race has been conducted.

I've sent email to the district email lists asking cub masters to please be sure to read the district rule set and that one in particular as there has been such a history of that rule being violated. Hopefully the communication will help reduce the number of DQs this year.

birddog



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Re: Have you seen issues with fixed axle location rules?

Post by rcmoeur » Tue Feb 18, 2014 7:07 pm

Four Peaks District Rules:
  • Wheelbase: 4.25" to 4.63"
    Wheel location: Anywhere, as long as 7" max length isn't exceeded
    Slots or holes are OK, but axle tips must be visible (more on this below)
(full rules and info at http://www.grandcanyonbsa.org/event/1459205)

The very first car that showed up for inspection at last year's Four Peaks District Derby had an noncompliant extended wheelbase. We directed the Cub and parent to the "pit area" table, which had an axle jig and #44 hand drill, and they relocated, resubmitted and raced successfully. Fortunately, that was the only extended wheelbase car we encountered.

If it was up to me, I'd allow extended-wheelbase cars, but my co-chair and Chief Judge definitely does not agree - so to keep Bob happy, we're maintaining the wheelbase rules. One new rule this year is that the axle tips will need to be visible. Bob and I know how to do this with drilled holes, but others may not, so we created a handy reference guide on how to create axle tip inspection holes (draft version at http://www.grandcanyonbsa.org/OrgsRichT ... letips.pdf) - we're hoping this is successful in informing entrants what's to be expected so the Cubs don't have to drill away the morning of the event. Bob wants the axle tips visible as a quick check for official BSA axles (US or CN) without requiring a pull or teardown.

--
Richard C. Moeur
Four Peaks District (Grand Canyon Council) Pinewood Derby Co-Chair



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Re: Have you seen issues with fixed axle location rules?

Post by DerbyAddicted » Tue Feb 18, 2014 7:45 pm

Richard, forgive my ignorance, but how can you identify Chinese axles by the tip? I understand about the American axles, but didn't know the Chinese were identifiable by the tip.

Now, back to the main topic. In previous years, we required use of the slot. In spite of that, we had a scout (actually the Grandfather) submit a car with an extended wheel base last year, and the car was disqualified. They ran home, and got their car from the previous year (which actually isn't against our rules) and raced.

This year, we allowed Scouts to drill their own holes with the following parameters: Wheel base measured axle to axle no shorter than 4 inches, no longer than 4 and three quarter inches. Unfortunately, we had a scout that had an extended wheel base and he slipped through initial inspection. When I gathered the cars for his Den's race, I immediately noticed it and mentioned it to the Cubmaster. The Cubmaster said that the car passed inspections and would be allowed to race (which I disagreed with). I went and readied the computer for that Den's first race, and once again as the cars were being staged, I voiced my opposition. I thought that it would be easier to remedy this before any cars from that Den raced. Once again I was shut down. Well this scout won all his races. When I returned the cars to the Pack staging area, I mentioned to the Inspector that he let an illegal car through. I'm not sure what happened, but sometime before the finals race, the Cubmaster DQd the scout with the extended wheelbase and bumped the 2nd place up to the finals. It was a really ugly situation. For the record, the scout had a dogbone shaped car, so it would have been impossible for him to "fix" it on location.

Now while I'm in full support of having no wheelbase requirement, I don't think our rule led to the scout's DQ. We distributed rules with the cars, as well as emailed the rules to the pack on several occasions. If a scout's family doesn't read the rules, then it falls on them imo.



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Re: Have you seen issues with fixed axle location rules?

Post by rcmoeur » Tue Feb 18, 2014 9:48 pm

My dislike for slots is kindled anew - this evening, while working on "P'u" (a block that came right out of the box at 127 grams, so I just had to build it), even carefully using all the proper tools and aftermarket guides, I still managed to pop a corner off the end. :burningmad: We'll see if cyanoacrylate can mend what was torn asunder.



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Re: Have you seen issues with fixed axle location rules?

Post by Shawn Stebleton » Fri Feb 21, 2014 3:11 pm

rcmoeur wrote:My dislike for slots is kindled anew - this evening, while working on "P'u" (a block that came right out of the box at 127 grams, so I just had to build it), even carefully using all the proper tools and aftermarket guides, I still managed to pop a corner off the end. :burningmad: We'll see if cyanoacrylate can mend what was torn asunder.
Are you able to drill holes first, then later on use a hacksaw blade or coping saw to cut a slot? Depending on wording and intentions of the rules and what they are inspecting for, that may work. Don't cut the slots until after everything else is cut/routed, etc. Perhaps that would help.


Shawn

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Re: Have you seen issues with fixed axle location rules?

Post by TXDerbyDad » Fri Feb 21, 2014 11:29 pm

DerbyAddicted wrote:Richard, forgive my ignorance, but how can you identify Chinese axles by the tip? I understand about the American axles, but didn't know the Chinese were identifiable by the tip.
Chinese axles have a cone tip, like this:
Image
(Those are aftermarket, not Chinese axles, but they look almost exactly like that)

US axles have the four sided pyramid-style axles. Chinese axles are also slightly smaller in diameter than USA axles.

But I don't understand the purpose of the axle inspection rule. I've not seen every aftermarket axle in the world, but since every aftermarket axle I have seen looks like either angled pyramid style US or cone tipped Chinese, what's the point in inspecting the tips? You're not going to tell if someone is using aftermarket axles by just inspecting the tip since they all look that way.

:idk:



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