Advice on Pack Rules for Pinewood Derby

Hey Guys --

I am back......

Firstly, got an email from council that they are going to modify the rules this year to allow:

1. Colored BSA Wheels purchased at the scout shop
2. May change the lubricant rules (TBD)

In addition - it looks like our Pack is going to adopt the district rules in order to ensure our kids can pass through to district races.

----------------------------

Now personally, I do have a question for you all (based on my sons design)

If I am to cut off the back of the car 5/8" of an inch from the front axle, and glue it to the front, and then still want a thin build design without using a tungsten canopy, what is the best way to accomplish that? Seems like a lot of weight to put in the front of the axle. In this design - what is the best way to weight the car?

Thanks again for all of the advice!
 
AAARacing said:
Hey Guys --

I am back......

Firstly, got an email from council that they are going to modify the rules this year to allow:

1. Colored BSA Wheels purchased at the scout shop
2. May change the lubricant rules (TBD)

In addition - it looks like our Pack is going to adopt the district rules in order to ensure our kids can pass through to district races.

----------------------------

Now personally, I do have a question for you all (based on my sons design)

If I am to cut off the back of the car 5/8" of an inch from the front axle, and glue it to the front, and then still want a thin build design without using a tungsten canopy, what is the best way to accomplish that? Seems like a lot of weight to put in the front of the axle. In this design - what is the best way to weight the car?

Thanks again for all of the advice!
Click to expand...
hmmm
I would try to get 12 tungsten cubes behind the rear axle if possible.
smile
 
Wow for once I agree with Rocket haha. My son wanted to do that on his car a few years ago and that car was THE most unstable car I have ever seen...Put the weight in the weight pockets leave the top for great graphics and stuff. Best of luck
 
I am sorry - and maybe a little dense (I am fairly new to this as last yr was our first car), but it seems like there is no way i would be able to fit cubes behind the axle.

So then that leaves me to creating 1 weight pocket in front of the axle. Then it seems like the center of mass is going to be too far in front of the rear axle, no?
 
So you are saying 2 rows of weights can fit behind the axle /images/boards/smilies/wink.gif

Excellent - my amateurish skills will be challenged!
 
yes cut the rear to resemble a squared off horse shoe (axle holes centered at 5/8" from rear of car, leave 1/8" wood then cut the pocket that will leave 1/2" which will accommodate two rows of 1/4" cubes)

if you wish to stiffen the axle area with some 1/64 plywood that is always a good idea
 
+1 for 5kids scout building tips. My only critic would be to maybe go with 2 rows of 10 .25" tungsten cubes behind the axle to be safe if you go really thin. Still being a league newbie, 12 in the back and 12 in front seems to always leave me with less then .5" COM and stability issues.
 
Hey - Guys, It is me again. We are moving along, and I am trying to put together a workshop for the boys for our scout pack and provide some good tips here.

Quick question for all here - With the district rules stating that we must have all 4 wheels touching, and put the axles in straight, is it best to center the weight in the car and TRY to attempt to run as straight as possible?

Thanks in advance everyone
 
Whether you are a new builder or a seasoned one, 5Kids web page is a must to learn how to build a car or just as a refresher.
 
You always want to rail run, and keep the weight in the rear. Do the rules mean the axles have to be straight or that you can't drill on a cant?
You may want to talk to John he's got a pretty awesome way of drilling a block to meet your needs then all you have to worry about is the prep.

AAARacing said:
Hey - Guys, It is me again. We are moving along, and I am trying to put together a workshop for the boys for our scout pack and provide some good tips here.

Quick question for all here - With the district rules stating that we must have all 4 wheels touching, and put the axles in straight, is it best to center the weight in the car and TRY to attempt to run as straight as possible?

Thanks in advance everyone
Click to expand...
 
+1 on the rules clarification. If you're not allowed to drill cant, you can also achieve camber via shims or set-screws. Find out exactly what you can and can't do so you know what you have to work with. There are some methods for setting up a 4-wheel-touching rail(ride/run)er, but you'll have to do a little digging.

Quicktimederby said:
You always want to rail run, and keep the weight in the rear. Do the rules mean the axles have to be straight or that you can't drill on a cant? You may want to talk to John he's got a pretty awesome way of drilling a block to meet your needs then all you have to worry about is the prep.
AAARacing said:
Hey - Guys, It is me again. We are moving along, and I am trying to put together a workshop for the boys for our scout pack and provide some good tips here.

Quick question for all here - With the district rules stating that we must have all 4 wheels touching, and put the axles in straight, is it best to center the weight in the car and TRY to attempt to run as straight as possible?

Thanks in advance everyone
Click to expand...
Click to expand...
 
Use only the Official Cub Scout Grand Prix Pinewood Derby Kit and official Pinewood Derby Wheels. (References: Cub Scout Grand Prix #33721A, Cub Scout Leader book #33221D, Cub Scout Leader How -To book #33832A and instructions provided in the Official Pinewood Derby Car kit #17006.)

The maximum overall width (including wheels and axles) shall not exceed 2 ¾ inches.

The minimum width between the wheels shall not be less than 1 ¾ inches, so the car will clear the center guide strip on the track.

The minimum clearance between the bottom of the car and the track surface shall not be less than 3/8 inches so the car will clear the center strip of the track.

The maximum overall length of the car may not exceed 7 inches. No portion of the car can extend past the starting gate/peg.

The wheel-base may not be changed from that of the official kit.

(The distance between front and rear axles must be at least 4 1/8. but not to exceed 4 3/8. (the standard grooves are pre-cut at 4 ¼.). You must use the axle slots provided in the kit and they are not to drilled, re-slotted, modified or changed in any way.

Weight may not exceed 5 ounces. The reading of the official scale is final. The car may be hollowed out and built up to the maximum weight by additional wood or metal (Mercury or Glass may not be used) all extras must be screwed or glued securely to the car.

Details such as steering wheels, drivers, spoilers, decals, painting and interior details are permissible as long as the details do not exceed the maximum length and width specifications.

Cars with wet paint will not be accepted.

Axels, wheels and body wood shall be only provided in the Official BSA Grand Prix Pinewood Derby Kit. The only exception is the official BSA colored wheels

(Official BSA wheels must be used. The wheels may not be cut, drilled, beveled or rounded. You may remove the seams and imperfections from the wheels. The wheels must show the THREAD marks on the outer edge. The axles supplied with the kit must be used, they may be polished or lubricated but not machined narrower.)

Axles may not be altered in any way except polishing. They may be glued in place, so long as a portion of the axel is visible to the judges.

Wheel bearings, washers, bushings, and hubcaps are prohibited. All 4 wheels must make contact with the track surface. (This is tested by free-rolling the car). And this is implied that the full wheel must make contact. Therefore the axles be in straight and the full wheel must be making contact with the surface.

The car shall not ride on any type of springs.

The car must be freewheeling with no starting device or other type of propulsion.

Only graphite or powdered Teflon .white lube. will be allowed for lubricating the wheels.
 
I just sent the rules. So I just want to be able to guide the scouts as best as possible, and I have looked at 5 kids site and will use a bunch of that, my question was just around weight placement. Yes - I know we want to push the weight placement in the back, but as far as DFW or Centered in the car, I didn't know if that changes based on the rules posted above
 
Ugh, what an unpleasant ruleset.

Things to definitely do:

- Weight your car advantageously. Get your CoM to the rear, and get the pine on your car nice and slim. Choose an aerodynamic profile.
- Polish the axles extremely well. Mirror finish.
- Prep your wheel bores. Novus 2, or consider a kit sold by DD4H.
- Make certain your rears are in good, straight alignment.
- Use good graphite. No teflon.

Things to possibly do:

- Cut about 1/4" of wood off of the rear of the block and glue it to the front with epoxy. Cut and shape as normal. This will get your rears further back and give you a better CoM and also position the weight of the car higher on the curve.
- Consider buying wheels trued for roundness. The BASX wheels sold by DD4H are probably a good bet. To be in perfect accordance with the rules, possibly see if he can produce you a set of the colored wheels.
- Look into methods for a 4-on-the-floor rail-guided car. This exceeds my experience, but I've seen discussions of such techniques.
- After the race, write a letter to the race runners and explain why their rules suck. /images/boards/smilies/frown.gif
 
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