Blue Ocean

My son and I are about to enter our first Pinewood Derby.
I'm in charge of the car's design. Sooo, I want to design a 911 for our derby car!
I started to draw the design on our wood block. Then I desided to do some research on derby cars. Wow. There's a lot more to this than I thought.
Man, there are some serious racers out there.
I've found several templates for wood block, but no 911's
I figured our cars were pretty aerodynamic so it should be a pretty good desing.
Understandably there are different factors to consider for this kind of racing. Of course I would like to win, but having a cool looking car is more inportant to me.
So here's the question. Any of you folks ever desinged a 911 derby car?
If so, did you use a template of just go free style?

Rudolph

My son won his pine wood derby some years ago. The key was a flat wedge shaped car with the all of the weight high and at the rear of the car and highly polished (dry lubed) axels and wheels. My dad made me beautifully shaped cars that I still have, but winning.....

TMc993

Just finished one with my grandson yesterday...I turned him loose with a hand sander and we pretty much eyeballed it. My theory was to let him grind on it until he got tired...Took about 15 minutes and he had the corners and edges rounded off and it looked pretty much like an old 50's style Offy Indycar.

We sprayed it with some fast dry spray paint then I gave him a small brush and he painted the stripes freehand (He's 6 so you can imagine what that looks like! )

It took both of us to attach the wheels but I made him use the drill, sander and apply the forces to put things together while I steadied everything...That way it's his car.

The key to these little cars is to get the wheels spinning freely (Xtra fine emery paper on the axles and graphite in the wheel holes helps) , get the car rolling straight (4-Wheel alignment ) and get the weight of the car as close to the weight limit as possible...The weight limit on my grandson's was 5 oz. and we had to add some weight to get it to the limit.

With so little weight, aero isn't that much of a concern...Gravity is the power source so weight and freely spinning wheels are essential...But aero is cool to look at isn't it?

Whatever you do, have fun with it.

ed devinney

I thought about making a 911 this year but wanted the fenders to cover the wheels. The standard block is a little short to do a 911, too. Next year I'll do it by gluing balsa to the top & sides. This year I built a hotrod VW:



Oh yeah, our pack runs a parent & sibling group just so that dads don't build cars for the boys. It's usually pretty clear when dads do too much. My son's car this year is a variant of his favorite design, very easy to make and it got 3rd overall when it ran with the pack in Paris, FR



I don't think aerodynamics enters into it at the speeds the cars run. Make sure the axles are polished, square to the car's body and well run in with graphite. Don't use petroleum greases, they slow the car down. Get the car as close to max weight as you can. Most of all, have fun building it with your son!

Don Plumley

Built them with my dad when I was a cub scout, and have made them with my son when he was a cub scout. Great memories.

The best thing you can do is let the kid do most of the work until they get tired of sanding, etc. Then let them use the spray can a few times, then ask if you can fill in a couple of places to touch it up.

The trick to winning is 1) get the weight right up to the max allowance, but using the actual scale that the Pack uses to confirm; and 2) lower the friction on the wheels.

We would drill holes in the underside and fill with molten lead and/or fishing weights with glue to get within a few 10's of oz, then go to the house that had the official scale and add just enough to be right on.

For the wheels, we'd chuck the axles into a drill press and polish using emery paper, then use dry graphite. I'd also chuck the wheels to round the profile just a little (in my day, they were really skinny tires) and make sure the were round. The smooth the inside of the wheel where the axle goes through.

But most of all, have fun!

Dudley

"highly polished (dry lubed) axels and wheels" is the key! We used a high grade silicone based lubricant and won. I mean my nephew won.

Blue Ocean

Everything I've read talks about polishing the axels. This seems to be the key. i found one site that says to use pipe cleaners chucked in a drill and run the pipecleaner through the plastic wheels to get out the inner inperfections.
The block is a bit long for proper porportions of a 993 but I'm going for it anyway.
Here's a pic of the design and I also found some plastic fenders that resemble the 993!

ppressle

I built a car with my son this year. He went for a car that looks like a loaf of french bread and I went for a Porsche 550. I wanted to do a 993, but the wheels were not close enough to the rear of the car to have it look right.re

My daughter did a car where she mounted some of her toy horses on basically a surfboard to create a stampede.

My son's car looks very fast in some test runs. Good axle and wheel prep. Axles in square to the block. Most of the weight in the rear and it is only running on one front wheel.

FlyYellow

i'm building one with my son as well. we were going for the 993 shape as well.

so far a lot of fun.

did you hack saw the cars? or did you only sand?

boris

ppressle

I roughed mine out with a table saw. A band saw would have been better.

I added 1/2" slices from another body for side slabs. I drilled the wheel wells and roughed out the sides before gluing them to the shaped main body. From there it was a little bondo and lots of time with a power sander w 36 grit.

If you add wood, you will need to hollow out the underside so that you can install the weight to the rear, (or even to make 5 ounces)