Graphite Pads - Pass it or Reject it?

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gpraceman
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Graphite Pads - Pass it or Reject it?

Post by gpraceman »

I see that ABC Pinewood Derby is carrying some new graphite pads that are meant to adhere to the car body and reduce friction when the wheel rubs against the body.

http://www.[no advertising for this vendor].com/graphite-pads.htm

So, if a car with these showed up at your race, would you pass it or reject it? Some could interpret these to be bushings.
Last edited by gpraceman on Tue Nov 21, 2006 2:02 pm, edited 1 time in total.
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Re: Graphite Pads - Pass it or Reject it?

Post by Mr. Slick »

Since it is an added part and not an integral part of the body/paint I would classify it as a bushing and reject it.
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Re: Graphite Pads - Pass it or Reject it?

Post by ranman106 »

I agree - bushing. I'd like to hear more thoughts on this as well. It's about time to refreshen the rules and this may need to be addressed.
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Re: Graphite Pads - Pass it or Reject it?

Post by gpraceman »

Mr. Slick wrote:Since it is an added part and not an integral part of the body/paint I would classify it as a bushing and reject it.
So, what about using glue with embeded graphite to reduce friction at those contact points? Would you also consider that to be a bushing and reject it? It is added (not really a part) but becomes integral to the body when it is dried.
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Re: Graphite Pads - Pass it or Reject it?

Post by ranman106 »

gpraceman wrote:So, what about using glue with embeded graphite to reduce friction at those contact points? Would you also consider that to be a bushing and reject it? It is added (not really a part) but becomes integral to the body when it is dried.
Homemade bushing. :?

I have no problem with rubbing the axle slot area on the body with graphite. It's just adding an extra "media" that cause me concern.
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Re: Graphite Pads - Pass it or Reject it?

Post by gpraceman »

ranman106 wrote:Homemade bushing. :?

I have no problem with rubbing the axle slot area on the body with graphite. It's just adding an extra "media" that cause me concern.
I would tend to allow the glue/graphite, but not allow these graphite pads or other types of bushings. However, some may argue that the glue/graphite makes a bushing. Though, a true bushing would be a replaceable part.
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Re: Graphite Pads - Pass it or Reject it?

Post by Stan Pope »

gpraceman wrote:new graphite pads that are meant to adhere to the car body and reduce friction when the wheel rubs against the body.
I'm not sure how to categorize the pad. My question is, rather, does it matter how effective the pad could be? Specifically, are there any car configurations that would allow the pad to make the car that benefitted from these pads competitive with a well-aligned car? If so, what are they?
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Re: Graphite Pads - Pass it or Reject it?

Post by Mr. Slick »

I'm just really tired of parents trying to buy a trophy rather than spending the time to work with the kids to figure out how they could reduce friction at the wheel/body interface.

I repeat, not allowed as a washer/bushing.

I have seen cars painted with graphite paint!

The suggestion that it may not be effective is weak at best. The vast majority of Cub Scout level cars are not aligned well enough to NOT benefit by any stretch of the imagination.
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Re: Graphite Pads - Pass it or Reject it?

Post by Go Bubba Go »

I would vote to reject it, esp. depending on what the pad is actually made of. A soft or flexible washer is still a washer. Same goes for the glue / graphite "washer". Not an integral part.

The borderline case I have considered previously is applying graphite to the area while the paint or lacquer is still wet, and very lightly pressing the graphite into the area, hoping for the graphite to become bonded or embedded into the paint/lacquer. Graphite added when dry would then hopefully (?) stick to the area rather than sliding right off. Upside, potentially better bonding and retention of graphite in the area. Downside, potentially rougher contact surface, esp. if not lightly sanded afterwards. Need to test.

Time permitting, I am considering building a block with multiple holes, each hole similarly sanded and prepped except for the variant above (graphite after dry vs. graphite while wet). Maybe 3 holes of each. Then using the same wheel and axle, moving from hole to hole, conduct spin time tests with the hub resting against the block. Need to think through the methodology to avoid skewing results. Any chances this has already been done?
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Re: Graphite Pads - Pass it or Reject it?

Post by 2kids10horses »

I haven't been to the website to examine these graphite pads, but from the descriptions, I would classify them as "bushings". I'll check the website...

I also consider a glue/graphite combo a "bushing". I'd allow a "paint/graphite" combo, however.

Our cars are deliberately NOT painted right at the hub-body interface. They are sanded smooth using 2000 grit paper, then impregnated with graphite.

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Re: Graphite Pads - Pass it or Reject it?

Post by psycaz »

I'd have to agree and its a bushing.
We do the no paint and rub the heck out of graphite into the wood as well as onto the wheel itself.
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Re: Graphite Pads - Pass it or Reject it?

Post by Stan Pope »

Whenever possible, rules should mean what they say. Better yet, the meanings should be reasonably accessible to reader using customary and readily available resources, e.g. a Mirriam-Webster dictionary, http://www.m-w.com/, as cited below.

If the rule precludes "bearings, bushings, and washers" then we should be able to determine whether the pads violate the prohibition by looking at the definitions of those three words.
bushing:
1 : a usually removable cylindrical lining for an opening (as of a mechanical part) used to limit the size of the opening, resist abrasion, or serve as a guide
Nope, the pad is not a "cylindrical lining".
bearing:
3 a : an object, surface, or point that supports
b : a machine part in which another part (as a journal or pin) turns or slides
Nope, the pad doesn't "support" and nothing "turns in it".
washer:
1 : a flat thin ring or a perforated plate used in joints or assemblies to ensure tightness, prevent leakage, or relieve friction
Hmmm ... it is "perforated" (there is a hole for the axle to pass through), it may be a "plate" and its function is certainly to "relieve friction".
plate:
1 a : a smooth flat thin piece of material
Close enough for me. But how would a typical Cub Scout parent interpret it? "Doesn't look like any washers my hardware store sells!"

Now for sensitivity analysis:
For most of us, common experience tells us that a washer is a loose piece of flat circular metal or fiber that slides coaxially between two surfaces.

Would a metal washer cease to be a washer (in form or function) if it were glued to the side of the car around the axle? I think that most would say that it is still a washer in form and function, even though the way its function is accomplished has altered slightly.

Would a large washer glued to the top of a car as weight be a washer under this rule? I think that, after thought, that most would say not since its function is not to "relieve friction."

Because the pad is difficult to recognize as a washer from most people's experience, I'd be inclined to either accept the pad or to qualify the rule in more detail. I'd hate to send a car home unraced because of a difficult to understand and/or interpret rule.
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Re: Graphite Pads - Pass it or Reject it?

Post by Mr. Slick »

Sorry about confusing bushing with washer. . . probably as irritating to some as when people confuse functions with procedures is to me! :D

I agree with Stan in that I would not send it home unraced. If a kid with a car shows up, it will race. It may not be allowed to get a trophy, but it will definitely race. These are times for the off to the side discussions with the parents who are "doing their best" rather than having the kids "doing their best". . . .

In my experience, those who push the rules are rarely in the trophies. I am wondering if this is since they are missing some of the tuning experience to get a really good running car?
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Re: Graphite Pads - Pass it or Reject it?

Post by Stan Pope »

Since a number of folks classified the pad as a "bushing", I'm wondering what their basis was. Is there a "dictionary of engineering terms" that I should be familiar with? Should the parents/mentors of youngsters also be expected to be familiar with that dictionary?

There seemed much disagreement on exactly how the graphite pad should be classified, even among experienced PW race mentors. That tells me that the rule is probably not well written. If we wrestle with its interpretation, how must the parent of a brand new Wolf Cub react? We need to do better.

We also need to look at racing methods that might allow a car to run in the races but not compete for the trophies. Including one or more "bandits" would warp the results of an elimination race format but not affect the results of a timed race format. Bandits could affect the accuracy of PPN or Stearns but probably not affect PN or CPN final standings formats.
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Re: Graphite Pads - Pass it or Reject it?

Post by SlartyBartFast »

Reject.
According to http://www.m-w.com/dictionary/washer it is unquestionably a washer ("a flat thin ring").
Need to have a clause in the rules that any and all commercial performance parts are strictly forbidden unless authorised by the Race Committee.
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