2012 Revised Rules

[*5 J's*]

rp - not ignoring your input, but I want a chance to fully evaluate what your rules allow and disallow, or what "types" of car I might expect to show up.

[pack529holycross]

You've restricted the wheelbase to 4 3/8". You've restricted the maximum distance between the front axle and the front of the car to 1 11/16". That means that the only way for the rear axle to be 5/8" from the rear of the car is if they remove 5/16" from the rear of the car, simply shortening the car. I don't understand why shortening the car is a problem. Lots of kids shorten their cars (either on purpose, or accidentally by sanding them too much).

Personally, I don't think moving axle locations is that hard for kids to do. And I certainly don't think that cutting a piece of wood off the block and gluing it back onto the block somewhere else is that hard for kids to do. But our rules are less restrictive than yours in a lot of ways.

Shortening a car is fine. Cutting the rear off and relocating is not. It's not a matter of ease - i's a matter of setting some basic boundaries. Such as weight at 5oz. It is easy to add more - but we set it at 5oz.

Someday we allow extended wheelbases - but for now we prefer to keep the "stock" location as it comes out of the box. We understand that the slots are not always parallel or square to the body so we allow drilling - as long as the dimensions are not changed from the slots.

please be aware that by using stock slot locations as a standard, you are creating a non standard standard, meaning that out of 10 blocks , perhaps 1 or 2blocks are identical or even close to each other and overall length. dis variation in length this is a relation in length results in a well documented condition of nonconformity. this condition does not a standard make. we address this discrepancy and I'm easily enforceable way. you don't even need a ruler " no portion of your car may extend beyond the starting pin, when positioned either forward or backwards. " this simple basic sentence will account for any locations of wheels, without having to get into 16ths of an inch here, 1/32 of an inch there. the bottom line for axel slots is not to provide a standard location, but 2 peas construction, otherwise there would be greater required tolerances in the manufacturing of blocks.

just my 2 cents from a race coordinator at the pack district and council level

[*5 J's*]

please be aware that by using stock slot locations as a standard, you are creating a non standard standard, meaning that out of 10 blocks , perhaps 1 or 2blocks are identical or even close to each other and overall length. dis variation in length this is a relation in length results in a well documented condition of nonconformity. this condition does not a standard make. we address this discrepancy and I'm easily enforceable way. you don't even need a ruler " no portion of your car may extend beyond the starting pin, when positioned either forward or backwards. " this simple basic sentence will account for any locations of wheels, without having to get into 16ths of an inch here, 1/32 of an inch there. the bottom line for axel slots is not to provide a standard location, but 2 peas construction, otherwise there would be greater required tolerances in the manufacturing of blocks.

just my 2 cents from a race coordinator at the pack district and council level

What kind of deviation are you talking? We don't measure down to the 1/32". We put the car into the Max-V box which is marked for the correct wheelbase. If the wheel look okay - it passes. Surely somebody could cheat us a 1/16" - but this, if done, would provide an insignificant advantage therefore I don't see the need to inspect to a finer degree.

I understand many eliminate this issue by allowing any wheelbase - I just don't think we are ready for that. I'm okay with the intent of our rule with respect to wheel spacing - I just want to make sure the rule is fair, enforceable, and not ambiguous.

[Stan Pope]

I'd encourage your district to scrap the "no-grooves" rule and the post race tear-down.

The advantage from grooves is neglible. Accomplishing grooves is within the ability of most.

The minimum axle diameter rule might be approached differently: Construct a gage from thin, hard metal that can slide between the hub and car body. If it will not go around the axle there, then the car passes the minimum diameter rule. The idea is that if that part of the shaft will go through the wheel bore, then the bore is not undersized!

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On axle locations: You can specify a wheelbase and a maximum distance from nose to rear axle. (But check the car's weight distribution to be sure YOU know which end is the nose.

[Darin McGrew]

Shortening a car is fine. Cutting the rear off and relocating is not. It's not a matter of ease - i's a matter of setting some basic boundaries.

Does it matter to you where the extra material on the front of the car comes from? Cutting the back off the car and gluing it to the front is bad. What about cutting the back off the car and gluing something else to the front? Your rules do allow decorations, and they do allow the removal of wood from the original block.

Anyway, I think the combination of maximum length, required wheelbase, and maximum distance between axles and front/rear of the car will prevent anyone from reconfiguring the car in this way.

[*5 J's*]

Does it matter to you where the extra material on the front of the car comes from? Cutting the back off the car and gluing it to the front is bad. What about cutting the back off the car and gluing something else to the front? Your rules do allow decorations, and they do allow the removal of wood from the original block.

Anyway, I think the combination of maximum length, required wheelbase, and maximum distance between axles and front/rear of the car will prevent anyone from reconfiguring the car in this way.

you cannot cut 1/4" off the back and then add a 1/4" decoration to the front end. This would effectively be relocating the axle locations. Axles should be no less then 15/16" from one end of the body and no more then 1-11/16" from the other.

[*5 J's*]

okay how about Stan's approach.

H. Wheelbase – The use of the pre-cut axles locations in the official pinewood car block is recommended but not required. The use of axle holes is allowed however the following dimensions must be maintained:
• Nominal wheelbase of 4 3/8 inches
• The rear axles must be located no more then 6 1/16” from the front of the car

The only issue with this approach is it doesn't give the builder the nominal placement of the axle holes for a full length car - that is 15/16" from one end and 1 11/16" from the other.

I really didn't expect this to be this hard. Other then councils that allow any wheelbase - how do other councils handle this? It can't be as hard as we are making it.

[FatSebastian]

What kind of deviation are you talking? We don't measure down to the 1/32".

This is an interesting question. We never thought about it because we never use the stock wheelbase or the axle slots.

I found seven discarded block bottoms and measured the distances using calipers from the front to the outer edge of the first slot ("Front"), the distance between the inner edges of the slots ("Wheelbase"), and the distance from the rear to the outer edge of the second slot ("Rear").

Code: Select all

	Front	Wheelbase	Rear 
1	1.715	4.128	1.027
2	1.651	4.300	0.903
3	1.655	4.291	0.912
4	1.649	4.292	0.904
5	1.658	4.289	0.913
6	1.649	4.300	0.910
7	1.663	4.302	0.909

The width of each slot appeared to be about 0.074" (which would need to be factored into a total distance), so based on these data points the average wheelbase was 4.346 (compared to 4.375 = 4 3/8").

What is more interesting is the sample standard deviation of these distances: Front = 0.023", Wheelbase = 0.064", Rear = 0.045". Assuming a Gaussian (normal) distribution, we might expect 5% of blocks to have a wheelbase that differs from the average by twice the standard deviation, or +/- 0.128", or ~1/8". (A larger sample would be more conclusive.)

[*5 J's*]

What kind of deviation are you talking? We don't measure down to the 1/32".

This is an interesting question. We never thought about it because we never use the stock wheelbase or the axle slots.

I found seven discarded block bottoms and measured the distances using calipers from the front to the outer edge of the first slot ("Front"), the distance between the inner edges of the slots ("Wheelbase"), and the distance from the rear to the outer edge of the second slot ("Rear").

Code: Select all

	Front	Wheelbase	Rear 
1	1.715	4.128	1.027
2	1.651	4.300	0.903
3	1.655	4.291	0.912
4	1.649	4.292	0.904
5	1.658	4.289	0.913
6	1.649	4.300	0.910
7	1.663	4.302	0.909

The width of each slot appeared to be about 0.074" (which would need to be factored into a total distance), so based on these data points the average wheelbase was 4.346 (compared to 4.375 = 4 3/8").

What is more interesting is the sample standard deviation of these distances: Front = 0.023", Wheelbase = 0.064", Rear = 0.045". Assuming a Gaussian (normal) distribution, we might expect 5% of blocks to have a wheelbase that differs from the average by twice the standard deviation, or +/- 0.128", or ~1/8". (A larger sample would be more conclusive.)

Agreed a larger same would be more conclusive - but if 5% of the blocks are off by 1/8" - I'm okay with that. I would say 1/8" is fairly insignificant with respect to it's affect on speed.

[Stan Pope]

The only issue with this approach is it doesn't give the builder the nominal placement of the axle holes for a full length car - that is 15/16" from one end and 1 11/16" from the other.

The suggestion implies the usual dimensions of axles in a full size block design, but it also covers shortened block designs.

The inspection should check for distance assuming both ends can be the front!

[Stan Pope]

The only issue with this approach is it doesn't give the builder the nominal placement of the axle holes for a full length car - that is 15/16" from one end and 1 11/16" from the other.

The suggestion implies the usual dimensions of axles in a full size block design, but it also covers shortened block designs.

The inspection should check for distance assuming both ends can be the front!

If it is a concern, you could observe, separate from the rules, the implications when applied to various cases.

[gpraceman]

We put the car into the Max-V box ...

Actually, it is the Lisano Enterprises' box, sold by Max-V

[*5 J's*]

We put the car into the Max-V box ...

Actually, it is the Lisano Enterprises' box, sold by Max-V

I did not know that. Thanks Randy.

[*5 J's*]

The only issue with this approach is it doesn't give the builder the nominal placement of the axle holes for a full length car - that is 15/16" from one end and 1 11/16" from the other.

The suggestion implies the usual dimensions of axles in a full size block design, but it also covers shortened block designs.

The inspection should check for distance assuming both ends can be the front!

Understood - I just like having the 15/16" and 1 11/16" in the rules for those that simply want to flip a block and mark it out. Having a rule that restricts the rear axle from being not greater then 6 1/16" from the front end resolves issues for a shortened car - but add's another dimension which may confuse builders.

I was hoping to simplify the rules but this seems contrary to my goal.

[Stan Pope]

I was hoping to simplify the rules but this seems contrary to my goal.

Lessee .... remove 2 dimension specifications, add 2 dimension specifications. Looks like a wash to me!

But wait! There's more! It shortens the rule, and it applies to all cases instead of one (albeit common) special case. That's a net gain!

Not only that ... your rule may be entirely silent on how to attach the axle to the wood. In separate commentary, i.e. outside the rules, or in your guidelines for inspectors, you could observe that the slots are present for convenience of some and say, "Nowhere in the rule does it say that you must use the slots!"