I am helping a young BoyScout build a PineWood Derby car. We have shaped the body to his liking and now were looking for some race tips.....Online their are many types of mods and advice....how about you? Got any secrets to win this race?
BoyScout PineWood Derby Car Construction.
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Lowe's has a small section dedicated to this single event. Pretty cool.
A friend of mine won handily two years in a row. His advice: slick the axles to keep friction at a minimum.
A friend of mine won handily two years in a row. His advice: slick the axles to keep friction at a minimum.
I just went through this with my youngest. In the past I've built cars that won, and recently our car was mid-pack. I made a mistake in the design.
There is actually another secret which I think is the biggest one of all... the center of gravity.
You want your car's center of gravity to be in front of, but close to, the car's rear wheels. Why? Because the weight has farther to fall. When the cars are placed on the track, the nose of each car is an equal distance, say, five feet off the ground. But where is the center of gravity of each car? The car with the highest center of gravity, within reason, has further to fall, and longer to gather momentum from gravity.
It may not seem like much, but it can make a huge difference in the end.
Our car this year... it had been a number of years since I last built one. After designing the body I was surprised at how much weigh was needing to be added, and so, more weight went toward the front, cutting down our COG, and making us slower once we hit the flat part of the track.
You don't want the COG to be too far back however. One car did that this year, weight way in the back, and the car becomes unstable and moves side-to-side, loosing momentum as it goes down the track.
There is actually another secret which I think is the biggest one of all... the center of gravity.
You want your car's center of gravity to be in front of, but close to, the car's rear wheels. Why? Because the weight has farther to fall. When the cars are placed on the track, the nose of each car is an equal distance, say, five feet off the ground. But where is the center of gravity of each car? The car with the highest center of gravity, within reason, has further to fall, and longer to gather momentum from gravity.
It may not seem like much, but it can make a huge difference in the end.
Our car this year... it had been a number of years since I last built one. After designing the body I was surprised at how much weigh was needing to be added, and so, more weight went toward the front, cutting down our COG, and making us slower once we hit the flat part of the track.
You don't want the COG to be too far back however. One car did that this year, weight way in the back, and the car becomes unstable and moves side-to-side, loosing momentum as it goes down the track.
Believe it or not, wheel alignment is also a big deal.
Possibly the most comprehensive resource out there:
http://www.stanpope.net/pwportal.html
Here are a few other good resources:
http://home.simplyweb.net/bosworth/index.html
http://www.goaskgrandpa.com/sample01.htm
Possibly the most comprehensive resource out there:
http://www.stanpope.net/pwportal.html
Here are a few other good resources:
http://home.simplyweb.net/bosworth/index.html
http://www.goaskgrandpa.com/sample01.htm
I guess its too late to pick the wood but are there rules on wood species and using knotty wood? I guess taken to the extreme you want slow grown knots of whatever the highest density legal wood is.
As others have said, the smoothness of surfaces and truing of axles and wheels are your #1 concern. Of course, you want the maximum weight you can have, too - and I mean really the maximum, use a 1/10th gram scale to be sure. Aerodynamics are secondary, so whatever the kid thinks looks cool is cool. I'd polish the bearing surfaces to a high mirror shine and use the best lubricant you possibly can. Liquid graphite may be all you're allowed. Maybe you could chuck the axles in a drill and spin the ends against a piece of 0000 steel wool. You don't want to remove too much material, however, because you'll make the wheels loose, so go slow. Polish the sides of the car on which the wheels bear to the same shine. A hard, smooth coating of something like acrylic nail polish on these surfaces might be good, as I'd be afraid that regular paint, varnish, or even bare wood could be a little more tacky and cause the wheels to drag against it. Polish the insides portion of the wheels where they meet the car using a peice of old denim for "sandpaper." It's probably best to not mess with the insides of the wheels, where the axles go, because that surface is probably already quite smooth, being cast. Still you could buy a few sets of wheels and pick the most perfect set using a micrometer, if one is available to you.
Not sure how to make sure the axles are perfect, but maybe somebody can provide some insight. I'd want there to be at most .010" deviation, but I'm not sure how difficult that kind of accuracy might be. Perhaps you could construct some kind of jig? Don't use a hammer to push the axles in, rather use a drill press to push them in smoothly, one by one, if you have one.
This sounds like overkill, but I grew up and was in boy scouts with a bunch of rich kids, and let me tell you, competition was cutthroat. At least two of the kids had actually put their cars in a wind tunnel at their dad's work to fine tune aerodynamics.
Not sure how to make sure the axles are perfect, but maybe somebody can provide some insight. I'd want there to be at most .010" deviation, but I'm not sure how difficult that kind of accuracy might be. Perhaps you could construct some kind of jig? Don't use a hammer to push the axles in, rather use a drill press to push them in smoothly, one by one, if you have one.
This sounds like overkill, but I grew up and was in boy scouts with a bunch of rich kids, and let me tell you, competition was cutthroat. At least two of the kids had actually put their cars in a wind tunnel at their dad's work to fine tune aerodynamics.
I have mixed feeling on this. Mostly it is an adult competition disguised as a boy scout event. The first two years my boy and I worked on the car but I tried to let him do most of the work only to run into parents that do all of the work and take away the purpose of the event from the kids. Then you have the parents that break the rules of the event with illegal lubricants and such. This year we didn't even build a car. I refuse to sit and make a car, as an adult, just to make my son look good...that's not how we raised him. If it was all about the kids...and the kids alone, he would be in it every year. I can understand the parents offering a little help, but the majority of the work should be done by the scout...which wasn't what was going on in his pack.
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Originally Posted By: ryansride2017
I have mixed feeling on this. Mostly it is an adult competition disguised as a boy scout event. The first two years my boy and I worked on the car but I tried to let him do most of the work only to run into parents that do all of the work and take away the purpose of the event from the kids. Then you have the parents that break the rules of the event with illegal lubricants and such. This year we didn't even build a car. I refuse to sit and make a car, as an adult, just to make my son look good. If it was all about the kids...and the kids alone, he would be in it every year.
I agree, it really is an adult event and I don't much like that, but I posted my response because I figure if you're in it you should be in it to win it. And the kid will feel good if he does well.
I have mixed feeling on this. Mostly it is an adult competition disguised as a boy scout event. The first two years my boy and I worked on the car but I tried to let him do most of the work only to run into parents that do all of the work and take away the purpose of the event from the kids. Then you have the parents that break the rules of the event with illegal lubricants and such. This year we didn't even build a car. I refuse to sit and make a car, as an adult, just to make my son look good. If it was all about the kids...and the kids alone, he would be in it every year.
I agree, it really is an adult event and I don't much like that, but I posted my response because I figure if you're in it you should be in it to win it. And the kid will feel good if he does well.
Originally Posted By: greenaccord02
Originally Posted By: ryansride2017
I have mixed feeling on this. Mostly it is an adult competition disguised as a boy scout event. The first two years my boy and I worked on the car but I tried to let him do most of the work only to run into parents that do all of the work and take away the purpose of the event from the kids. Then you have the parents that break the rules of the event with illegal lubricants and such. This year we didn't even build a car. I refuse to sit and make a car, as an adult, just to make my son look good. If it was all about the kids...and the kids alone, he would be in it every year.
I agree, it really is an adult event and I don't much like that, but I posted my response because I figure if you're in it you should be in it to win it. And the kid will feel good if he does well.
Yes but too many times a scout wins without as much as lifting a piece of sandpaper. Sends the wrong message: Daddy will do it for me and cheat to win. We can do without it.
Originally Posted By: ryansride2017
I have mixed feeling on this. Mostly it is an adult competition disguised as a boy scout event. The first two years my boy and I worked on the car but I tried to let him do most of the work only to run into parents that do all of the work and take away the purpose of the event from the kids. Then you have the parents that break the rules of the event with illegal lubricants and such. This year we didn't even build a car. I refuse to sit and make a car, as an adult, just to make my son look good. If it was all about the kids...and the kids alone, he would be in it every year.
I agree, it really is an adult event and I don't much like that, but I posted my response because I figure if you're in it you should be in it to win it. And the kid will feel good if he does well.
Yes but too many times a scout wins without as much as lifting a piece of sandpaper. Sends the wrong message: Daddy will do it for me and cheat to win. We can do without it.
Like I say, that's a great theory and I tend to agree with it, but it's hard to explain this kind of a philosophical position to a 10 year old. He wants to win. And I think he should be given every legal advantage since he has decided that he wants to participate. I think the boy should take an active part in the project, of course, and there's nothing I wrote about doing that a child couldn't do with proper supervision. This is an event that teaches woodworking, design, physics, and engineering lessons as well as important life lessons about cutthroat competition and doing your best while keeping the moral high ground (not cheating to win like others will).
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I hear what you're saying, but Cub Scouts is really a family activity. It's by design that Dad or an appropriate adult gets involved. Usually, the 8-year olds cannot and should not handle the power tools needed to do many of the tasks in the construction. So, I had my 8 year old do some things... he did the initial drawing on the block of wood. I did the band sawing, obviously. I did some power sanding, he did some finish sanding by hand. I inserted the weights and he helped glue them in. I put the wheels on (after polishing the axles to a mirror finish) and he painted the car.
I think most of them are like that, or they should be.
Now, cheating is another matter. You simply must follow the rules.
If you can get the boy and the dad to spend time together building the car, the event is already a success.
I think most of them are like that, or they should be.
Now, cheating is another matter. You simply must follow the rules.
If you can get the boy and the dad to spend time together building the car, the event is already a success.
Originally Posted By: crw
There is actually another secret which I think is the biggest one of all... the center of gravity.
Discovered that by accident.
My car was an ugly door stop of a car that consistantly won. my dad set up the block in the mitre box and supervised the use of the saw but let me make the cuts.
"Good work son. Now here's some sandpaper. Sand it until your arm feels like it is going to fall off and then sand it some more..."
The weight placement was just dumb luck. Liberal use of graphite was just me being a kid with tired arms who was starting to get sloppy.
I dominated pack, did okay in district but didn't make it to council. Too many dad build cars with too much attention paid to things like alignment and rolling resistance.
But I had fun and my ugly little doorstop beat some really well crafted dad built cars.
My next(and last car) was a lot prettier and more aerodynamic but bad weight placement meant I didn't even win at the pack level.
There is actually another secret which I think is the biggest one of all... the center of gravity.
Discovered that by accident.
My car was an ugly door stop of a car that consistantly won. my dad set up the block in the mitre box and supervised the use of the saw but let me make the cuts.
"Good work son. Now here's some sandpaper. Sand it until your arm feels like it is going to fall off and then sand it some more..."
The weight placement was just dumb luck. Liberal use of graphite was just me being a kid with tired arms who was starting to get sloppy.
I dominated pack, did okay in district but didn't make it to council. Too many dad build cars with too much attention paid to things like alignment and rolling resistance.
But I had fun and my ugly little doorstop beat some really well crafted dad built cars.
My next(and last car) was a lot prettier and more aerodynamic but bad weight placement meant I didn't even win at the pack level.
Back in the 50's, think we were 7-8 yr.-old cub scouts. Most dads did 95% of the work. One kid had a bad weight problem, academic difficulties, and was poor. His dad drilled out the bottom of the car and filled it with lead (the kid told us). He won easily and nobody ever said anything cause I guess we were so glad to see him win something.
Originally Posted By: jimbeamalki
His dad drilled out the bottom of the car and filled it with lead (the kid told us). He won easily and nobody ever said anything cause I guess we were so glad to see him win something.
Didn't they weigh them back then? Everone was weighed at my sons. One wants to have the maximum weight allowed. That's what the weight kits are designed for, in addition to the other pointers.
His dad drilled out the bottom of the car and filled it with lead (the kid told us). He won easily and nobody ever said anything cause I guess we were so glad to see him win something.
Didn't they weigh them back then? Everone was weighed at my sons. One wants to have the maximum weight allowed. That's what the weight kits are designed for, in addition to the other pointers.
Interesting storys and advice. At this point, we are not going to buy into the many (aftermarket) official parts...just have some fun. The boy made his body trace, we cut it with a bandsaw and did some power sanding. He finished off by hand. we have moved the axles up to lower the car to 3/8 inch limit. Moved the axle spacing further apart. Used 45 caliber slugs and some holes drilled just back from mid center of car. The car now weights about 4.5 oz. We drilled a inch hole on top dead center. A water bottle cap fits tightly in the hole. Now at weight time we will add bb's to get the weight right to 5oz and make the Scout Master happy. He is going to paint the car red and black. We will polish the metal axles add some dry graphite and get ready to race in 3 weeks.....sounds like fun. Thanks again, LCM
Power tools? Way back when, Dad whittled my car out with his pocketknife- but then, he was a good whittler! Sandpaper of course, smooth & polish the nails/axles, graphite for lube, lead for weight(max 5 oz, yes?)- sounds like not a whole lot has changed. Glad to hear it!
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I was at a PWD race recently. The winning car was shaped like a military Humvee...FWIW.
Let us know how it turns out, best of luck!
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