pinewood derby car rules

[Gonzo1 10]

Webelos II son has Pinewood Derby this weekend. His car is almost done. Here's my question: Is is mandatory that the car axles be placed in slots, or can we use pre-drilled holes? Do you know where it states this in the rules?

 

Gonzo

[ScoutNut 147]

The rules are not "National". They are mostly up to the individual Pack, but most follow the rule sheet in the PWD box. If your District runs a District/Council PWD, then their rules are the ones the Packs will go by.

 

If you do not have District/Council PWD rules, then you should ask your PWD Chair your question.

 

Most Packs I know of (mine included) do not allow solid axles or the wheels to be moved. This is done to insure fairness, that everyone is on as uniform a base as possible.

 

 

[eagle-pete 11]

Gonzo

 

Scoutnut is correct. You should have a committee formed. This committee should create the pinewood derby rules for your pack. They also become the ruling committee incase of disputes.

 

There are many, many, many resources both in BSA and on the internet for Pinewood Derby. One of my favorite places on the net is: http://www.geocities.com/~pack215/pwd-rules.html

 

That site is a virtual cub leader handbook, and although it is not Official BSA, the site does keep their info up to date and they follow BSA policies.

 

Eagle Pete

[Eagledad 2777]

Hi Gonzo

 

As one who enjoys tinkering with these things and pushing the limits, why do you want to drill the holes? I'm trying to imagine any reason other than insuring perfectly perpendicular axles. Depending on what you find out on the rules, you can still fill in the groves with wood filler or even glue and then drill them out. I don't see that giving you any advantage and still accomplishing your goal.

 

I love this pinewood derby stuff

 

Barry

[MarkS 11]

As everyone said, rules are local. For example, in my old pack... solid axles were prohibited and BSA wheels and axles were required for fairness, precut blocks from kits were permitted to simplify the build (because the shape of the car doesn't matter in terms of performance--except for how it affects the center-of-gravity), and the slots in the blocks didn't have to be used (to make the kids think and use their ingenuity).

 

If done right, extending the wheelbase of a car will improve stability and permit the to roll straighter down the track (less rubbing means less friction and more speed). It will also provide the design with more flexibility in positioning the center-of-gravity to maximize potential energy at the start while maintaining that sability down the track.(This message has been edited by MarkS)

[packsaddle 753]

Way back when I was cubmaster, one of the things we did to make this more fun was to invite all the boys and families to a series of 'tune up' sessions. All the dads (and a mom or two) brought their tools and the basic car kits in whatever state of assembly they were in.

At the 'tune up' meetings (really a series of evenings over a couple of weeks prior to the derby), all the boys got to compare designs. The dads and moms talked about tools and methods.

AND, importantly, everyone was able to learn about the 'official' rules included with the kits. In our pack, the pack supplied the kits to all the boys so everyone had the same basic starting point. The 'tune ups' helped level the field with regard to tools, etc.

At the last tune up, I brought a calibrated balance for the official 'weigh in'.

 

Later, at the district level, I did the 'weigh in' as well. My balance was reviled because many of the cars didn't meet the weight restriction. AND I was absolute about the qualifications. Some dads went to their machine shops and manufactured perfect, polished axles and did similar things to the inside of the wheels. One guy actually hid all this inside 'fender skirts' so I couldn't inspect the vehicle. Liquid lubricants were not allowed. I disqualified a few cars from the official competition but we allowed them to race unofficially. Amazingly, the car with the hidden stuff beat everything else hands down. Did the boy build it? I can't say for sure. Did it use the same wheels and axles as everyone else? I can't say for sure. Was it illegally lubricated? No way to tell. So it finished first...unofficially. The dad was really angry. The boy, for some reason, just hung back quietly, almost as if he was uninterested.

We also had a design competition. There were a surprisingly large number of boys who didn't much care about speed. They wanted to win the best design...and they had some good ones, too.

Our pack handed out real trophies for the first three places in each age bracket and medals for everyone else. I also printed really nice certificates for everyone. I can send you my design template if you're interested.

I have said this many times in these forums: I really miss the cubs.

[Jeffrey H 25]

In our District, you must use the nails, wheels, and block that comes in PW Derby car kit. No exceptions. If you dont use the pre-drilled axle slots, the wheels still must be same length and width from each other. We basically follow the rules that come in the box so the cars will not have any problem running on the tracks.

[Eagledad 2777]

>>If done right, extending the wheelbase of a car will improve stability and permit the to roll straighter down the track (less rubbing means less friction and more speed

[SSScout 1615]

Pine wood derby...

 

Our District has a couple of Troops that keep really fine, "professional" tracks , timers, stands, posters and flags etc which they "rent" out to the Packs as a service. The "starter" of one is really good, lots of patter, talks up the quality of the car and the Cub. "START YOUR ROUTERS!!!" etc.

 

We always had a "Cub" league ('On Your Honor', the Cub did MOST of the work...)and an "Adult-Unlimited" league, and an "EE" league (everybody else. Siblings, guests, etc). The District enforced the Package rules, and the various Packs knew it in advance.

 

Good recruitment tool.... Our Pack had a roughed out wood track that we brought to PTA picnics, and verily the draw of boys was great...

A lot of fun.

Google for lots of hints and tips.

 

YiS

 

[gwd-scouter 11]

While each pack in our district may have its own rules for pinewood derby, the District Derby has a long established set of rules that is posted on the website and talked about many months before the event. Essentially, the car must adhere to the block dimensions of the kit even if you use your own wood, use the wheels and axels (pegs) that come with the kit, and fit into a mold that has been made for measuring the dimensions of the car. Only the powdered graphite is permitted. Even with all the rules posted, there is always someone who shows up with a non-regulation car (most times clearly not made by the Scout) and arguments ensue.

 

Please forgive me that I don't specify the exact regulations, but I believe they are very close to those in the kit and it has been a few years since I've chaired the District event.

 

To go off topic a bit and add some shameless boasts, my older son has been asked to be the emcee and official starter of our District PWD Derby for the past five years. Originally asked when he was a Boy Scout to help out, he's in his 2nd year of college now and was asked and is coming home again just to do this next month (hey Barry...he "loves this scouting stuff"). Younger son is also helping as the pit crew for his 2nd year checking in and handing out the cars during race time. A District Pinewood Derby legacy in the making!

 

Ah, there are many times I reflect and truely miss the Cub Scouts.

 

 

 

[Gonzo1 10]

Thanks for the great replies.

 

This is Mason's last event for cubs as he crosses over next month.

 

In the past, he had a "boy made car" and boy did they ever look like it too! Rough, jagged edges, sloppy paint, but he made the cars.

 

This years, his mom and I thought we would but a kit car, pre-cut. We chose the standard wheel base model. Supposedly, this is a fast car. With the car sanded, painted and assembled, it's 5.0 ounces at the post office scale. Instead of getting a car with the grooves for the BSA axles and whels, we opted for pre-drilled holes. It's a very low profile car with weight in the back over the rear axle. We're using the BSA axles and wheels. The real question is, must we use the grooves? It would be as though we cut the car into a top half and bottom half, but we made the car from the top half, no grooves.

 

Please advise.

 

G(This message has been edited by Gonzo1)

[OneHour 11]

Barry,

 

You asked ... "why do you want to drill the holes? I'm trying to imagine any reason other than insuring perfectly perpendicular axles. Depending on what you find out on the rules, you can still fill in the groves with wood filler or even glue and then drill them out. I don't see that giving you any advantage and still accomplishing your goal."

 

Some folks drill their own holes 1) keep the center of gravity below the axles plane, thus providing more stability as well obtaining more potential energy; 2) to extend the wheel base to move the center of gravity further back on the car (most Packs' rules disallow both of these).

 

This year Gonzo and Barry, I'm trying a different idea on my Open Race car that I got off DerbyTalk.com, rail riding. The concept makes perfect logical and theoretical sense ... by having the car rides the rail all the way down, you would maintain constant velocity. Granted that the rail will provide friction; however, it is impossible to maintain "a constant straight run." Sooner or later the car will be bouncing against the rails, how many times will depend on how perfectly alignment the car is. So every time that the car hits the rail, it acts as a break which then forces the wheel(s) to start up again instead of maintaining a constant speed and velocity against the rail.

 

The race is tonight. I will let y'all know the results!

 

Gonzo,

 

You wrote: "This years, his mom and I thought we would but a kit car, pre-cut. We chose the standard wheel base model. Supposedly, this is a fast car. With the car sanded, painted and assembled, it's 5.0 ounces at the post office scale. Instead of getting a car with the grooves for the BSA axles and wheels, we opted for pre-drilled holes. It's a very low profile car with weight in the back over the rear axle. We're using the BSA axles and wheels. The real question is, must we use the grooves? It would be as though we cut the car into a top half and bottom half, but we made the car from the top half, no grooves."

 

The answer lies within your Pack's pwd rule, whether or not BSA original axle slots have to be used. Packs like ours will require for everyone to use the original axle slots. This is to make it fair for all boys. Not everyone has the luxury of power tools such as a drill press.

 

Either way, I (and several of the more "interested" dads) have found that the luck of the Irish lies in the wheels and their treatment! Here are the right combinations to make a car very competitive and your Webelos can do this!

1) The weight has to be 5.0 oz or 4.99999 oz. Either way, get it close to 5 oz.

 

2) The weight needs to be closer to the back (assuming that the "short end" of the block will be your back) with the center of gravity about 3/4" in front of your rear axles. This is aggressive back-weighing.

 

Also, the weight distribution needs to be 4oz is supported by the back wheels and 1 oz by the front. Use something like books at the same level as the scale and straddle the car across the two with 1 set of wheels on the scale and then take the measurements.

 

Once you have all this then your son will need to work on the most important factors ... the axles and the wheels:

 

1) If you do not have time to slighly sand off the ridges on the axles, don't worry! Just mark where they are and have them installed up! Meaning the bottom of the axle is the smooth, already polished part will be the part that the wheel bore will be riding on. Just make sure that you file the ridges off (under the head of the nail). Spin some graphite on the axles.

 

2) The wheels can be lathed or lightly sanded to where they run flat!

 

3) This one, I learned from Derbytalk.com (Stan Pope): assemble the wheel/axle and align it to run perfectly straight and true, ie. no shimmy, no run-in or out, etc. It was pointed out that you can use small cuts of wax paper to shim the axles to make sure that the wheels run straight. It actually works! Previous years, my car in the Open always finish 2nd or 3rd and I noticed that it did the "shimmy" down the track. Folks on the board told me that it is way off alignment. This year, I aligned it according to suggestion and did not notice the car moves from side to side during the test rolls.

 

Finally, spin in the graphite. If you have a dremmel, chuck a buffing pad and use it to spin (at lowest rpm) the wheels with! Squirt some graphite into the bore and touch the buffing pad to the wheels. This will 1) impregnate the graphite into the bores and axles; 2) simulate many heats. Keep on lubing the wheels until you get 25+ sec spin on your wheels and they spin quietly.

 

Something to also try if you want to go further ... 3-wheelers and rail-riding! There are a lot of great info on Derbytalk.com. Those folks are very knowledgable and helpful. Apparently, they compete at a much higher and more professional level than we and our boys do! If you have questions, PM me and I will try to help. I'm not a professional at it, but I have been having fun with my three sons so far!

 

Ahhh ... the smell of pinewood and the feel of anxious scouts ... It must be pinewood derby time again!

 

Good luck

 

1Hour(This message has been edited by OneHour)

[Gonzo1 10]

Thank yo for all of your comments.

 

The CC says the holes are OK. The car weighs 5.0 ounces. I didn't do anything to the axles, I had already installed them before I read these comments.

 

The center of gravity is about where OneHour said to put it.

 

We'll find out tomorrow how his car performs.

 

Thanks,

Gonzo

[OneHour 11]

Gonzo,

... now your son will need to spin a lot of graphites in! Lots of graphites!

 

Good luck!

 

1Hour

 

ps: My Tiger finish 3rd in his rank tonight. He was one happy Tiger!

[Gonzo1 10]

We applied the graphite, spun it in well. He won some races and came in second or third in others. We use a four lane track.

 

Unexpectedly, he came in Second Place for "Best in Show" and he's pleased with that.

 

Thanks for all the tips.

G