Pinewood Derby - a different perspective.

With Pinewood Derby coming up and being tech week, I thought I'd share my speed secret. The GMP model reminded me of this Pinewood car. Besides all the well known speed secrets like turning axles down, etc. Stop and look at the track from a different perspective. Design a car to have an advantage based on the track design.
Most tracks have a peg in each lane that manually rotates down into the track to let all the cars go at the same time.


Ok, hear me out. If your point of contact is only at the top of the peg and the center of the car is gone, your car will gain a rolling advantage. We built this car, and had a ROLLING car length head start at the gate. The spoiler wing on the front is necessary to trip the light with the front of the car at the finish.
The fact that it is a Front Engine Dragster with two engines helps with style points too. Hope this helps put a little different perspective on car designs for you dads and grampas this pinewood season. Make sure you check out the particular track, and maybe design the car accordingly. I don't have any build pics, but it was cut from a single standard isuue block of wood. Also notice in the mirror all the weight. The more wood that is cut away, the more weight you can place where you want it. We put a lot of weight in the center of the car low. Pics are worth a thousand words. Hope this helps some of you with some ideas.

 

It all depends on what the cub scout pack will allow you to run, or not. If enough people cry "foul", the car may not be able to run.

Our pack had a wooden box that the car had to fit into, anything hanging out of it was declared illegal and had to be removed. I had to take some neat rub rails off a modified one time, lost some weight out of the deal.

I concentrated on machining my wheels to a +/-.0005 tolerance, cleaning up the axles, getting the CG in the right place and lots of graphite on the axles.

I have more tricks, but don't usually share them. I do have a "chassis jig" for axle hole drilling.

Bob

 

Hmmmm........that's a different thought! Just a little Gasser Stance could be an advantage then.

 

Congrats on becoming the Smokey Yunick of Pinewood Derby.

 

That's funny, BTW - everything does fit in the box. Everything should be legal, but I could feel the whole room staring us down when this little car was halfway down the track before the rest started rolling - that was a little uncomfortable.

 

OCEANSIDE?? I made 3 lexan go/no go jigs for my sons pack, left them when he moved on, to Jr. Dragsters.

 

poor kids dont have a chance with smokey on the grid.surprized they still allow lead.shame on you ,go get em

 

Your son is quite the craftsman...

 

Do you want to teach your children to have fun, or be winners? All kidding aside, we didn't win anyway because the front spoiler was not on it. The beam didn't trip until the engine crossed. Karma? This powerful information has been shared with you, how you use it is up to you.

 

I'm out in Suffolk. We had a pretty competitive pack though. Everybody looking for the edge.

Bob

 

Always good to shake up the troops with some innovation that gets all the dads grumbling. I was always subtle about what I did. My kids did the car, I handled the wheels, axles and weight placement.

The biggest thing I stumbled upon was they used a postal scale to weigh the cars. It had a LED display and they taped off the display so it would display one decimal point. So a car that showed as 5.0 ounces could actually weigh 5.099 ounces and be legal. I weighed my kid's cars at work on a gram scale.

Bob

 

All the "CNC dads" were complaining about my son's car, because the paint and body was nice and smooth. Mrs. Yankee was in earshot when they started grumbling to the pack leader (William got top honors for craftmanship) and quietly walked over. "Actually gentlmen, our son did the car by himself- if you look on the left side, you'll see a couple spots where he forgot to sand out some cut marks"...

They stopped complaining after that .

Did I mention just how much I love my wife?!!!

 

I was Cub Master for 9 years an what was really sad was a boy from a broken home. The mother didn't know the difference between a saw and a file but he still had fun.

 

We had this situation too. Our way to make it fair was to have a separate "outlaw" category for more adult inspired cars. We tried to truly keep it so that the boys honestly competed against each other. The outlaw was for dads/adults and the fastest car won. Boy did we see some cars.

 

I actually had some father congratulate ME on a job well done. I corrected them all, it was him! My son did a candy fade paint job and would have won if his car hadnt run off the track ( the weight was too far back and it wheelied off the track). They put it on with one wheel going the wrong way and came in mid pack. He had won (by large margin) all the other heats. He even beat the other father built cars!

 

That just made me laugh out loud.

 

That's a great idea! How about just letting he dads build their own cars altogether? I can't wait to have a boy scout of my own and build cool derby cars with him.

 

When you beat the rest of the field by at least 6 feet on each run, they really glare. Just explain to the other people that this is truly a physics test about potential energy, moment of inertia, and frictional heat losses. Most are so uneducated that they just walk away. Grooved axles to hold graphite, lightened wheels, 3 wheeling, and proper weight placement here. Tried to do the front wing on the pin thing but it ended up over top and wouldn't work.

 

thank you for this thread, this brings back so many memories of me and my dad building our pinewood derby cars. between the two of us we kicked a lot of cub scout ass to the curb lol. We built one one year that had Yoda from Star Wars driving, beat everyone by 4 car lengths, they were checking the car for batteries and electric motors. must have been the force. lots of good memories. I bet a lot of guys got into cars from racing those things. Oh yea and the twin MGB Gt's, i wish I knew what happened to them. He had a red one and I had a blue one.

 

For God's sake let the 8 yr olds do it!

 

My seven year old wanted to cheat more than I would let him. His car was ugly but fast. Some people just have the advantage of tools at their disposal and dads willing to help them use them.

 

We have a dad's class... they still CNC their kid's cars...


Just got the new rules for this year's derby- NO modifications to the wheels except for "removing trhe flash".

Honestly, I like the idea of no wheel mods. The new wheels are a heck of alot better this year and it evens the playing field a bit more.

 

it's more fun to share the car with your dad, i will always have memories of that, i came up with the idea and was involved in the car too, no cnc stuff, the idea was to build it as a team, not for the adult to do the entire thing.

 

http://www.jalopyjournal.com/forum/showthread.php?t=449873&page=6&highlight=pinewood
GUILTY as Charged!!! Me and my sons built ours,,, but it was my fingertips next to the whiring blades of Death,,not theirs.
Speaking of wheels,,I narrowed them on the front of the front eng dragster and got "caught".

 

If you are allowed to change the wheelbase, longer is faster. CG of the car 1 1/4" in front of the rear wheel centerline.

 

You can alter the wheel base, but the car cant be any longer than 7 inched.

 

On the track I was involved with, the front weighted cars went down the hill fastest, but the rear weighted cars were faster on the flat part. So I being the bastard that I am, designed a car with movable weight transfer. Plastic tube with valved mercury transfer.

The car was never beat. Too bad I wasn't that devious as a child.

Nuts

 

Pinewood Derby is an excellent introduction for the young guys in case they want to get involved in real racing later in life. They learn:

1. Everybody cheats.
2. The guy with the the most tools usually has the best chance of winning.
3. Whoever bitches the most can usually browbeat the officials
4. If your car isn't fast at least you can make it look pretty.

 

How did you accomplish this???

This info will only be used in the parent division.

 

I loved pinewood derby's. It was my favorite part of scouts. Our model a club does a similar race but with old Hubley Model A's.