Pinewood Derby 101 - painting a car and getting a smooth finish - need help

[Jerry McCaffrey]

"Edwin Pawlowski" wrote in :

Jerry

[Mark Jerde]

Do the rules permit building several and fielding the best one?

-- Mark

[Fred Goodwin, CMA]

Your son can build as many cars as he likes (and as many as you can afford!), but he's only allowed to enter one car. And our Pack does not allow boys to "reuse" a car from previous years -- each entry must be newly built for that year's race.

[Dan Valleskey]

Serious answer in my next post. ~~~~~~~~~~~~~~ Signs you are getting carried away with your ( or is it- your son's?) pinewood derby car-

Your Cub Scout now knows how to measure in thousandths of an inch

You showed up the night before, when they were setting up the track-

You tried to calibrate your dietary scale?.

If you bought a book about how to win at Pinewood Derby, you might be getting carried away.

If you know that 5 ounces is 141.7 grams?

If you used a dial caliper or micrometer?

If you used a pocket calculator at any time-

If you used a heat lamp to cure anything

If you made a box just to carry the car in

If you bought more than one type of lubricant.

If you used a jewelers loupe- you might be getting carried away.

If you needed a metal turning lathe, because your wood lathe had too much runout when dressing the wheels-

If you used cad software in the design stages?.

You had to buy anything mail order, because neither the corner hardware store nor the Scout Office had what you needed-

You sketched out a quick Gantt Chart-

If your Tiger Cub now knows how to wet sand?.

If your budget went over 50 bucks?.

If you had to run out to buy more rouge (polishing compound) ?.

If you used a router at some point in the construction of your car, you might have spent a bit too much time on it.

If you used a wind tunnel, you might be getting carried away with your pine wood derby car.

~~~~~~~~~

[Dan Valleskey]

I think all that really matters is wheel alignment and smooth axles and wheels. The areodynamics are way down the list. Weight is, of course, assumed to be brought right up to the limit. Measure in grams, (141.7 if memory serves) you will likely have better resolution on your weigh scale.

Some say the weight needs to be toward the rear.

The wheels should have been on a day or two before the competition. (I know, hindsite is 20-20). Roll the car down a sheet of plywood, over and over, watch to see where it goes. Bend axles accordingly.

Yes, pull them suckers off, yank the axles anyway you can. re-drill, and re-set, if you still have time. Otherwise, push, bend, whatever. You will see a very very slow time at the rate of turning you have now.

if you are re-drilling anyway, drop the car a few thou. You should drill for the axles at around .218 up from the original bottom. That will leave you the required 3/8 inch ground clearance. Use a #44 drill.

tighten up on the 1/16 to 1/8 space you talk about. Look at toe in, are the wheels sitting stright up and down?

Our pack runs a Dad's class. Takes some of the heat off some of the boys. Including mine, I am sorry to say I really want him to have a fast car. He just wants one that looks cool. So we have compromised.

The dad's class turns out some pretty fancy stuff. The rules are..... bent. Last year I got tromped by a guy that used wheels he turned off a CNC lathe. Tall wheels. His frame was carbon fiber screwed to a little bit of pine. He works for a race team here in Indy. His kid had the winning car in the boys class. My wife asked his kid, how did your car get such a nice paint job? He said, I don't know. Later I heard the boy say he was not allowed to touch his car.

Sour grapes? Maybe a little, I came in second place with stock wheels. And my kid lost to his kid.

This year, we are backing off a little, I am not building a car at all, my kid is handling all body duties on his car, I will just handle his axles and wheels.

Okay, maybe I need help!!!! But the boys will all have fun, anyway.

-Dan V.

[Mike Patterson]

I remember when I was a Scout and some of the kid's dads would do that stuff. My dad wouldn't help me out at all.

He said I would learn better that way.

He was right, I learned very well that some "men" who consider themselves to be "good fathers" are in actuality selfish children who are teaching their kids that the rules don't apply to "them".

After the second or third such race, I never did pinewood derby again. Why waste the time?

Boy, I'm amazed at how pissed off I am 30 years later...maybe I need a shrink, or a few hours in the shop.

Got an idea for a tongue & groove headboard...

Mike Patterson Please remove the spamtrap to email me.

[Silvan]

[Silvan]

Check. (But then again setting up the track is one of my jobs as a leader, so I only get half a point here.)

Check. (My (son's) car came in at 5.0 oz. on the real scale too, so it must have worked well enough, eh?)

Negative. But when a guy who was moving on to Boy Scouts gave me a bunch of those books, I read them.

I do know, so check.

Check.

Negative.

Half a point. The stuff I was trying to cure actually sloughed off.

Half a point. I ran out of time to make the box. So I put it in a padded box some lathe tools came in, which I filled with packing peanuts.

Negative.

Negative. But I don't own one.

Negative.

Negative.

Negative.

I don't even know what that is.

I didn't know they had invented Tiger cubs, so I never had one.

Negative.

Check.

Negative.

I would have if I had had one.

How do I score this thing. Am I hopeless? :)

[Scott Duncan]

My son and I just went though this and my beef is with the race format. My son?s car was the fastest car based on time but he didn?t win a major trophy because they use a point system based on race position instead of time. My son?s car lost one close race against another fast car so it was out of the running as far as points are concerned. There were 66 cars but only 5 races with three lanes so each car only races 10 other cars. The undefeated cars won trophies but they didn?t race against my sons car ? they only raced slower cars. The car that beat my sons won the third place trophy but the combined time for my sons car beat the first place car by a significant margin. My son?s car also had the first and second fastest individual runs. I?m going to work the pack leaders next year to try to refine the format so that the fastest car has a better chance of winning. (does anyone know of any?)

We did win the ?best paint job? certificate so I can tell you how to paint it. The best part is that you can have your kid do as much as the work as you or he wants to. We started with a spray can of sandable automotive primer and put about 5 coats of primer on it and sanded between each coat with steel wool. My son is a seven-year old so he was only good for about

15 minutes a day so this worked out well. He tended to dribble the paint a little so we would sand of the dribbles with 220 paper. We bought a can of lacquer spray paint for the finish coats and repeated the process with multiple coats and steel wool. After about three coats it was done and we left the final coat alone. The whole painting process took us about two weeks to complete. The paint job is very shinny and smooth with no signs of wood grain. Just about everyone who sees it seems to need to feel it to see how smooth it is.

I can also give you a few tips on how to make your car fast. The slots have to be aligned so the car goes straight - ours was aligned right out of the box. You have to polish and lubricate your axles and wheels and you can find directions on how to do this on the Internet. Our wheels would spin for about 20 seconds when we were done. Perhaps the most important thing besides making sure the car goes straight is to put the weight in the back of the car. Remember that potential energy is equal to weight x height so the higher up that weight is sitting on the ramp, the more potential energy the car has. That extra potential energy is transferred to extra kinetic energy on the flat section of the track. All of the finalists in this race had their weight in the back. Another thing we did was to built the car to be slightly overweight and then removed weight at the weigh in. Our entry was exactly 5.00 ounces on the official scale.

Happy racing...

Scott

Mike Patters> >

[Swingman]

"Refininf the format" is what happens when parents get involved in things that are better left to the kids.

Should be like a horse race to me. In large futurities, there are ten heats of ten horses (chosen by a draw), with the winner of each heat running in the final race. Whoever crosses the finish line first in each race is the "winner" of that race, elapsed time be damned ... that is the way "racing" should be.

Anything else is politics, not racing.

[Scott Duncan]

That?s pretty much the way the races were run before digital timers and computers. Since this equipment has advanced, many packs have switched to time based racing. Some even have an initial run to sort the cars so that faster cars are racing faster cars and slower cars are racing slower cars. This benefits the slow cars too, because the will win more heats since they are racing with other slow cars. Randomly mixing the faster cars with the slower cars makes for lopsided finishes and some kids going home with our finishing well in a single heat. There were some pretty long faces at the end of the day at our race. On the other hand, matching the cars beforehand makes for close, more exciting finishes with a good chance that everyone will win at least one heat. With a format like this, however, fastest combined time is the only metric that makes sense for selecting the trophy winners.

My son will get another chance for a trophy in two weeks because his car has moved on to race at the District level. Our pack selected the fastest car from each den to race against the other packs.

Scott

[Swingman]

I guess I am just old fashioned, Scott. :)

Every race, as does life, has elements, like luck, bad or good, that make things unfair ... just seems like it would be a good time for a kid to learn that.

[Edwin Pawlowski]

That is sad. He won the race but lost a lesson in life. The dad's ego is more important than his son accomplishing anything. The rules should be change so the kids build the cars under the supervision of the scout leader and they not be take home where they can be "tampered" with. Ed

[Scott Duncan]

Well put ? good point.

The flip side is that, we, as adults know that life isn?t fair and that hard work doesn?t always pay off in the end. The question is then, at what point do we teach this lesson to our kids?

Scott

[Swingman]

My formative years were on a farm in the 40's and 50's, so I doubt you would be surprised to learn that I was raised that the sooner you learned to live with life's disappointments, the better. :)

To me, that's one of those "tough choices" a responsible parent has to make, and many don't seem want to want to face. When you get right down to it, it's all in how you, the parent, approaches each challenge the kid faces, and prepares them for it.

Lest you thing I'm just spouting off ... my youngest, 18, is a "special needs" kid who has faced a lot of challenges in life thus far. I'd be lying if I said there wasn't a lot of sadness involved as a parent, but our biggest source of pride, and hope for the future, is in the _heart_ this kid has shown. She garnered a 4.0 GPR last semester, in mainstream classes in a large urban High School, and came up 80 places in her graduating class, to graduate this coming summer in the top 50% of the class with an overall HS GPR of 3.2 ... all of which got her an acting scholarship at the recognized university of her choice.

To her, she is not "disabled" at all, she just knows she has to try harder ... and does.

Being the oldest of my siblings, I agree it's a lot tougher raising a kid today than what my parents had to face.

[Dave Mundt]

Yea...I feel your pain there. My parents would point me in the direction of where to FIND the information I needed to do a project, It was typically a VERY rare occasion when they would do any significant work on my project. It always annoyed me NO end that other kid's parents would do 90% or more of the project...even if the kid wanted to work on it. I think, though, in the long run I was the real winner, as I ended up a lot more self-sufficient, and resourceful than many of these other kids.

Well, that is a hard question to answer.... One way that the scout troops that my nephew is involved in deal with it is to STRONGLY urge the parents to let their kids do the work...and they have an unoffical "parents" catagory where the adults can run their cars against each other. I know of one family down that way where the dad has actually built a raceway of their own, to specs, so they can tune their cars. It has been my observation that the trick to speed is to ensure that the wheels are straight on the body, so the car does not scrape against the center guide. Friction is your enemy here, and, it is amazing how quickly rubbing against that center line will slow things down.

Haw! It DOES seem that the injustices of youth burn all the stronger in one's mind! I suppose it has to do with one's feeling of how much control over one's life there is. As a kid, we are VERY controlled...so since we can't do much about injustice, it is even more annoying than when we are adults and CAN do something about it. Good luck getting over it! I know that I have a few things that still rankle (although my issues are more with School Science Fairs).

Good deal! Always nice to turn that energy to something positive...I have been remiss myself in that...I have several projects that are rotting away from neglect that I really need to get finished up. Dave Mundt