My son Justis and his pinewood derby car...We need your help!

I just made a car a few weeks ago for a business sponsorship derby for the local cub pack. I was amazed at how close the times were. The winners were running 2.50's and I was running in the middle around 2.55's (such a nerd that I still remember ET's). Given that, be sure to have fun and not stress the kid out too much about it, since being competitive can be a lot of effort for incremental gain.

But like everyone else said, it is all about axle prep. Be sure to check your pack rules, since some of the suggestions so far would have broken the tech inspection at the pack I ran with (lathe turning the axles and sanding the running surface of the wheels was expressly forbidden).

 

My Dad and I made an Auburn... that was 30 years ago! I wonder what happened to it -I'd love to show a pic of it!

 

My son and I built a 57 Chevy pinewood car. I was going to the academy for corrections back then and I smuggled the body and paint to my dorm room to finish it. He won the award for best looking, got second for speed. Great time with the kids and doing something as a family.

 

We had an "unlimited" class when I was a scout - I kicked some major ass with my swamp boat style propeller on the back of the car. Good times!

I like the idea of getting an old track and using it as a get-together for the guys...

 

When I was a kid and my dad help me build mine it was carved like Davey Allisons #28 Thunderbird and we drilled holes in the bottom and put lead in the holes from his body working supplies! They didnt weigh any of them... I won hands down! hahaha!

 

That would be called "Progress", just look at the evolution of drag racing.

 

Here are pics of the ones My Dad and I made back in '68 - '70. Mine were made 100% by me w/ my Dads guidence but he never touched one. The Pink one was made by Dad for Mom. The " Garvic " copy was hand carved as was his attempt at a GTO.

And the 2 First Place trophy's

 

Never lost a race....4.99 in weight
Wheels, where the axle slides inside the wheel hub, polish internally! Then polish the hub area on the inside and outside of the wheel...Polish the axles, never sand, once you think it's the best you can do, polish it another 100 times....for weight, the more towards the back, winning speed comes at the bottom of the curve on the track not at the start. Don't worry about aerodynamics.

 

Make sure you get the 'alignment jig' from Hobby Lobby or ??? to get perfect alignment on the wheels/axles !! Set it, AND DON'T TOUCH IT !! Most kids are rolling them all over tables/floors etc. between the races and jackin' up the alignment. Check it after each race and handle carefully !! Graphite in between rounds as well !

 

what are your rules?
Can you mess with the tires?
Can you change axle location?
how big can it be? long/tall
How are the cars released?
what is considered crossing the finish line first part past or tire?

We need to know the rules before we can bend them.

 

Here's the fleet built by my dad bro and I.












And heres one my dad made when he was a kid.

 

This one is sweet!

 

From a physics standpoint, the farther back you can get the center of gravity, the more potential energy you start with. The weight is falling farther. You need a long car with little weight in the front. Limit the friction on the tires and body and make sure the axles are parallel.

 

pretty much everything thats been said is right on....keep your weight back as far as you can w/o flipping,make sure it tracks straight,polish the axles(if your pack will allow it notch them so the graphite has someplace to stay(in my sons pack thats fine as long as you use the nail in the kit),rub graphite on the body where the wheels will rub,graphite the hell out of the wheels,spin,repeat about a million times,pack the wheels again and leave it until race day,and it should work out well.
worked out great for my son last year(as you can tell by the smile!)

good thing about the whole pinewqood derby thing is he hates hanging out in the shop but this is weening him in and getting him interested in cars.
last years roadster...

and this years coupe...

hes done everything on both(with me helping guide and occasionally hold a hand while doing it) except stripe/scallop them

 

My boys scout pack had over 130 cars this year. Cool thing was they had an "Outlaw" class for the parents. This helped keep the kids doing most of the work them self..........kinda. Keep those wheels square, polished axles, and most of the weight in the back and have fun!! My fastest........sorry, OUR fastest time was 3.002sec. NEXT YEAR UNDER 3!!!

 

Axle/Wheel prep and weight are the biggest factors.

Chuck up the nails/axels in an drill and knock down all the ridges, then smooth them with fine steel wool and 320/500/1000 grit sand paper makem shine! Then check out your nearest scout store most have the "special" tools, wheel arbors, axle guides ect.

The new wheels are fantastic a lot better than in years past. They could still benefit from spinning them with the wheel arbor and run them on some wet 1000 grit sand paper to make sure they are absolutely smooth.

Remove as much wood as possible so you can put the weight were you want it, just in front of the rear wheels. Make sure to graphite the axles/wheels and spin them with dremel wheel to break them in.

That will put you in the running, there are a ton of other tips/tricks/legal cheating that you could go nuts with but save that for the dad race.

Let the kids design/ paint decorate it anyway they want and have a blast. Below is this years car anbd yes the blue wheels are BSA approved. Last years car was a slingshot dragster

 

Thanks for the help guys, we start next week!

 

I'd like to thank you guys as well. We just finished my sons car. I found an axle polishing kit thanks to comments on this thread. The wheels spin forever so it should do well. I had searched Google for the last 8 years building these cars and never got the ideas you guys posted.

 

Good luck Guys! Brings back good memories of my son and I working together on his cars.

 

speedracer

 

We had two and the pick-up (less aerodynamic) was so much faster. It was right on at the allowed 5 ounces. There were a few really detailed cars but the were so much slower. When I installed the wheels I shimmed them with a piece of paper and then pulled it out. It was said earlier about this, if there is too much play here, it will slow you down dramatically. Good luck

 

My son won in his den today thanks to the H.A.M.B.

 

http://www.lazardev.com/physics_of_pinewood_derby_cars.htm

Does this guy know what he is talking about? The race is in 2 weeks!

 

I know his oil idea doesn't follow the rules we have. We have to run dry lube. I graphite the wheels and tires in a bag for a while before the race. I forgot about the sticker trick to hold more graphite on the hub. The angled nose idea makes sense.

 

Chessy or not?

 

I like it. Cool and smooth looking.

 

Reminds me of this one


http://www.jalopyjournal.com/forum/showthread.php?t=516553

 

this year i did not go hab friendly but i like how it turned out

 

Looks cool!

 

1 week to go!