Pinewood Derby - Page 3

Dozer523 · 02-08-2010, 11:12

Here are a few shots from the Preliminary run. Note the difference in styles. And that is Little Dude and his best bud - chief competitor. I wonder if they realize how lucky they are to have each other as "wingmen" at such an early age.
BTW I need to find about .005 of a second. I'm open to suggestions.
einherjar we used your car design as our base. Thanks (I think "cars" should look like cars.)

Snaquebite · 02-08-2010, 11:43

Quote:

BTW I need to find about .005 of a second.

1. Lengthen the wheel base. (If allowed)
2. Some folks believe raising one of the front wheels off the track creates less friction. Never tried it though.
3. Center of gravity, 1 to 1 1/4 inches in front ot the rear wheels. Keep the weights low in the body. The car should balance somewhere between 1 and 1-1/4 inches in front of the rear axle.
4. Once you get the wheels correctly aligned, use a small amount of super glue to keep them that way.
5. Take a pipe cleaner and polish the inside hub of the wheel. Most folks don't think about this.
6. When you lube the axels, don't just add a few puffs of graphite. Spin the wheels and work the lube in the hub. Then add a little more on both sides of the wheel.

If your rules allow:

1. Make a round paper hub cap to glue onto the wheel after final assembly of the wheels and axles. When the wheel moves towards the car body, the hub cap contacts with the axle cap before the wheel can touch the car body. The spinning wheel and hub cap just touch in the very center of the axle cap resulting in minimal friction. Even better if you put a bit of graphite in the hubcap before final glue-down.
2. Shave down the wheel width so they look like bicycle tires. This causes a very thin track contact point for less friction. It also has less mass in the wheels meaning less inertia and less energy to get the wheels spinning at the start.
3. The cap on the axle touches the plastic wheel across its surface. This means for friction to slow down the wheel. Grind away the outter side of the wheel so a thin circle around the axle hole is higher than the surrounding wheel. This causes the wheel to touch the axle cap close to the center where there is less energy wasted.

Edited to add: these last three mods are a little difficult for the kids to do.

Happy Racing

LarryW · 02-08-2010, 11:53

Quote:

I wonder if they realize how lucky they are to have each other as "wingmen" at such an early age.

Sure looks like they know. Great pics, sir!

Dozer523 · 02-08-2010, 12:08

Snaquebite, I'm callin' the entire pit crew in tonight. The car is going back up on the lift.
We're going to work on the alignment. -- hubcap idea merits some thought. Major source of frustration was the open slot for the front axles. Did not offer the tighness and support; and any downward pressure messes up the alignment. Solved that by covering the slot with a piece of popcicle stick.
We'll look at the weight placement, too. Thanks.

Snaquebite · 02-08-2010, 12:17

Dozer, sounds like fun....good luck.

For any who have not seen this it's worth a look. Funny Movie.

http://www.downandderby.com/home.php

ZonieDiver · 02-08-2010, 12:46

Congrats to you and the Little Dude, Dozer.

**Razor** · 02-08-2010, 14:33

Congrats to you both, Dozer! Be sure to check the District rules before you do any modifications to wheelbase, wheels or axles--you don't want LD to be DQ'ed for something inadvertently. One year, we did raise one of the front wheels about 1/32" higher than the other three to reduce rolling friction. I don't know if it made a significant difference in overall performance, but that car was also a 1st place pack finisher. If the District rules are pretty strict on modifications, I'd recommend doing the axle-and-wheel-in-the-drill routine with LOTS of graphite (better do it outside to keep momma happy) several times every day this week. The more graphite gets imbedded in the wheels' axle channels, and the more the axle pin and channel gets burnished, the less friction the car has to overcome. Good luck!

Dozer523 · 02-17-2011, 19:34

bumping this to the front.
It's Pine Wood Derby time.
For those just joining us, there is invaluabe advice here.

We have already spent 2 days working on the axles and wheels alone. We are going with the weights internal. Last year we had them mounted underneath and forward. We were good on the Pack track but didn't have enough clearance at the Council. At the last second we had to move the weights to the roof but we still did well. Thanks again.

mojaveman · 02-17-2011, 20:16

Many years ago (40 to be exact) I was a member of the YMCA Indian Guides and not only participated in, but actually took first place in a pinewod derby competition. Can't remember all of the regulations regarding construction but do remember that Dad and I added the melted lead fishing weights to a 3/4" hole that was bored in the top of the car just behind the rear axel. It made the required weight perfectly. I remember that during my constant wins the judges weighed the car several times to make sure it was within regs.

alelks · 02-17-2011, 21:37

NICE! This time of year we weight a a few of those for our customers since we have two sets of certified scales that weight down to the 1 tenth of an ounce.

NoTime89 · 02-17-2011, 22:18

I am a life long scouter (Cub to Eagle) and my parents were a tremendous help. It takes a village...

That homage being said I remember my oldest brothers first Pine Wood Derby:

He was excited. He had just opened the box kit and I heard him across the house. (Wasn't that hard--Army housing in some spots are like bunkers, in others reminiscent of the lumber they give you in that Derby box).

Like most Pine Wood Derby's, my dad immediately took this as a challenge and he spent long hours tutoring Andrew on aerodynamics, resistant airflow techniques, and rates of gravity/mass.

The creation: a crescent shaped metallic purple shaped 'car' that was covered with sand across the top.

He and Andrew spent hours fine tuning that car, working long hours to get the right weight in the right area.

He ended up getting beat by a 3 wheeled uncrafted block that one kid was allowed to race.

If I'm lyin', I'm dyin'.

My dad then started focusing on the 'DESIGN' portions of the event. We had a tank, magic schoolbus, and Log Truck. The Truck was my favorite, it had dowels cut down to lay in the back. Looked great. I can post pic's if you guys want.

Do your packs still do Regatta's?

Dozer523 · 02-09-2012, 16:29

Bumping this to the front.
It's Pine Wood Derby time. AGAIN!
For those just joining us, there is invaluabe advice here.

this year we're going with the "wedge" with internal weights.

greenberetTFS · 02-09-2012, 20:37

Quote:

Originally Posted by Dozer523

Bumping this to the front.
It's Pine Wood Derby time. AGAIN!
For those just joining us, there is invaluabe advice here.

this year we're going with the "wedge" with internal weights.

Go for it Dozer and I hope you and little dude make it to the finals again !!!!........

Big Teddy

Snaquebite · 02-09-2012, 20:46

Did the scroll saw cutting last week on my girl's grandson's car last week... called me today wanting to come over a do some fine tuning after he sanded it down.... lots to do this weekend....his race is the 18th.

mugwump · 02-09-2012, 21:19

Ah, Pinewood Derby time. I loved it back in the day. I had a big box of cast .45 bullets and an accurate scale so I was the "weighting" guru. No one ever went over weight. It was never cutthroat back then in the way I hear it can get now. Everyone shared ideas. Enjoy these days they go by so fast!