HELP!!...pratice tonight car problems

[elkie]

cool. i think i'm finally getting all this, too bad i wasn't able to work more on this the last 3 weeks

The gate is a manual gate, so would i cut the angle in the front to look like this / or like this \

For the back weight, use epoxy, with weights sideways in the void area(inside the rails)

[doct1010]

Angle the front slightly from bottom = /. I would place the horizontal bar weight in rear just infront of the axle, pot it in epoxy if need be. Put the coffee pot on you are in for a long one !! You could also, if you are feeling particularly ambitious, drill holes in back of car to hold bullet weights. Not sure you have enough wood betwwen axle holes, however if there is you could lower weight further by drilling four 1/2" or 3/8" holes in back. Then place weigths in recess with taper facing out. Looks cool and lowers wieght as well!

[Lucky13]

I concur with that prescription, Doctor!

Elkie, you still have weight BEHIND the rear axle. It's ok to have some weight back there, but in an ideal world, ALL your weight would be just in front of the rear axle.

I see that you have a void there. But, 5 minute epoxy will hold weight up against the horizonal surface of wood. That will get the weight lower. That bar would be closer to the track, which will make your car more stable. And it would bring that weight a little more forward. That will allow you move that weight that you have resting across the middle of the car a little more back.

A perfect car would have ALL the ballast just in front of the rear axle. And below the axle plane. That is, low on the body, or on the bottom.

With that style body, it's ok to squeeze weight in between the rails.

Duct tape will hold it!


2k10h

I agree with most of what 2K10H is saying, but, having ALL the weight in front of the rear axles is not always the ideal location. Back and low is the way to go if you want to be fast, you just need to make sure the alignment is good. If your not so sure about the alignment or if it's a rough track then I would come more forward on the weight placement. Good Luck with the race !!

[Doug Piranha]

with most of what 2K10H is saying, but, having ALL the weight in front of the rear axles is not always the ideal location. Back and low is the way to go if you want to be fast, you just need to make sure the alignment is good. If your not so sure about the alignment or if it's a rough track then I would come more forward on the weight placement. Good Luck with the race !!

Lucky13,

I agree that SOME weight behind the rear axles is good IF the car is set up correctly. But, for a quick repair, stable is the way to go and that means most or all of the weight right in front of the rear axles.

Low weight is good but low weight behind the rear axles still lifts the front wheels.

The best formula we have come up with is 1oz behind and 3oz just ahead of the rear axles.

That seems to work every time. We came in 2nd and 3rd out of 4,500 cars and were beat by a car with all of the weight in front of the rear axles...

Kurt

[doct1010]

Lucky, agree with Kurt on this one. I believe 2K would also. We have multiple pack winners and a recent district winner. Weight is always low, some below plane and almost entirely in front of axle. Set up is critical as is axle and wheel prep.

[Davhamm]

...Did you align per stans procedure?

Were can one find this procedure?

Thanks

[doct1010]

Dav,

Find a post by Stan Pope click on his web page. His online book "Learn to Build a Winner" may be the best resource on the web, except for DT where you get him live!

[2kids10horses]

Guys, I base my "ALL the weight s/b placed just in front of the rear axle" on my observations of Jay Wiles (WarpSpeedINC)'s car "Snuffleupagus". It was the WIRL stock winner for 2005, and it had all the weight just in front of the rear axle, and it was a large tungsten cylinder. He did have a tiny tungsten cube behind the rear axle, but he said he had to add that after the initial design was complete, and he had no place else to put it. The reason he had to add it was he was developing his "Inertia-Lite" wheels at that time, and he was getting his wheels lighter and lighter. The weight removed from the wheels had to go somewhere, and that was the only place he could put it! There was hardly any wood to it.

The bottom of Snuffy was set at exactly 3/8 inch off the track, and the bottom of the tungsten cylinder was visible. So, not all the weight was below axle, but a significant portion was. The little tungsten cube stuck on the back hung down as low as he could get it.

So, I base my comments not on what I THINK is fast, but what has been proven to be fast. Heck, I'm not smart enought to think this stuff up! But, I try to apply the principles can learn from those that ARE smart enough to think this stuff up! And, I try to give credit to those I have learned from.

2k10h

[doct1010]

Guys, I base my "ALL the weight s/b placed just in front of the rear axle" on my observations of Jay Wiles (WarpSpeedINC)'s car "Snuffleupagus". ....So, I base my comments not on what I THINK is fast, but what has been proven to be fast.... And, I try to give credit to those I have learned from. 2k10h

Good enough for me as well and has worked quite well!

[gpraceman]

So, I base my comments not on what I THINK is fast, but what has been proven to be fast.

Well, it does depend on the track (wood or alumininum, short or long, smooth or rough, tight curve or gentle curve). These variables can make the "optimal" COG placement be different depending on the particular track. Snuffy ran on a smooth aluminum Best Track (I think a 42ft one).

[pwdarchitect]

Yep,, 42' aluminum Best track.

[2kids10horses]

You have valid points about Snuffy running on a smooth aluminum BestTrack. If you anticipate running on a rough track, a more conservative setup is appropriate. (I don't have the tooling or the skills to build a car like Snuffy, but I can apply the principles of what made it fast to our cars. Or, at least TRY!)

Our car will have to run on three different tracks this year. (Hopefully!) Our Pack track is a wooden track with rough joints. District will be on an aluminum BestTrack, and the Council race is on a 54 foot aluminum track. We built to maximize performance on the most important race: District. It's the qualifying race to get into Council.

And, your design and weight placement is dependent upon what materials you have to work with. Using a material like tungsten allows the builder to put mass in a more compact space than the builder who uses zinc as ballast.

This year, we used the tungsten plates. As I showed in my construction photos, not all the weight is in front of the rear axle. About 1 oz is behind. But below the axle plane. But, if there were a readily available material that would have allowed me to build that design but would have placed all the weight in front )of the axle, I would have done it. (I think Stan has a call out for Plutonium. A more toxic substance cannot be found! )

I think I made my comments starting with "Ideally..." If not, I should have. We all try to build what we think will be the ideal car, but we all have to compromise somewhere along the line. But, that's part of the fun, trying to figure out which combination works best.

2k10h

[joe]

I haven't made a 3-wheeler whereby I can adjust the weight freely. However, I have done so on a 2-wheeler. No question that the 2-wheeler was quite a bit faster with as much as 2 ounces behind the rear wheel, as opposed to all the weight being concentrated in front of that wheel. I have tested many configurations, and the concentrated weight does not work in this case.

[2kids10horses]

We've really strayed from the topic of this thread, which was to help get Elkie a better performing car for today's race.

Hey, Elkie! How did you do?

2k10h

[TAL]

Yea Elkie ,
Show a photo of the final result of the car, and how did you do at the race???