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someusername wrote:

iwonder wrote:
Skidding at the beginning of the run or the end of the run? They seem like heavy wheels, which could cause them to skid at launch (if your launcher is quite fast).

I don't believe that they are skidding at launch. It's a simple falling mass launcher (I am still developing a spring launcher). But they skid about 20cm when going for the 9m distance.

On another note, what is a good mass for the wheels and a good mass for the car? I'm Still fairly new to this event.

Your car is definitely moving too quickly for your brake, since 9 meters is the closest distance and you are using a spring launcher. As I stated earlier, rubber or foam can stop the issue.

As far as the mass, for the car anything around 300 g should be okay, it is always better to be lighter to go faster etc. The mass of the wheels depends on the size you want, small wheels= more turns but are lighter, and vice versa.

InfiniCuber wrote:
Your car is definitely moving too quickly for your brake, since 9 meters is the closest distance and you are using a spring launcher. As I stated earlier, rubber or foam can stop the issue.

As far as the mass, for the car anything around 300 g should be okay, it is always better to be lighter to go faster etc. The mass of the wheels depends on the size you want, small wheels= more turns but are lighter, and vice versa.

What kind of rubber or sponge so you think may work. We have tried this gradual stop using springs, but they kept getting caught in the threads. We also have tried nylon tubing, but that didn't seem to help much either

someusername wrote:

InfiniCuber wrote:
Your car is definitely moving too quickly for your brake, since 9 meters is the closest distance and you are using a spring launcher. As I stated earlier, rubber or foam can stop the issue.

As far as the mass, for the car anything around 300 g should be okay, it is always better to be lighter to go faster etc. The mass of the wheels depends on the size you want, small wheels= more turns but are lighter, and vice versa.

What kind of rubber or sponge so you think may work. We have tried this gradual stop using springs, but they kept getting caught in the threads. We also have tried nylon tubing, but that didn't seem to help much either

The standard trick is wrapping the wheels with cut up ballons or rubber bands, I'm not sure how well the rubber bands would work on your wheels, but the ballon should hold on fine.

As far as springs, with a lot of nuts jammed together to form a stopping point it might be easier to use rubber washers instead, so that could be worth a shot.

In the rules, they have a bonus shot option with a tin can, but they don't specify how to go for bonus points. At regionals and states last year, I didn't see any can. Can anyone shed light on this?

gladiolatrue wrote:In the rules, they have a bonus shot option with a tin can, but they don't specify how to go for bonus points. At regionals and states last year, I didn't see any can. Can anyone shed light on this?

The can is new this year. Rule 5.d. explicitly describes how to get bonus score points.

iwonder wrote:

someusername wrote:What kind of rubber or sponge so you think may work. We have tried this gradual stop using springs, but they kept getting caught in the threads. We also have tried nylon tubing, but that didn't seem to help much either

The standard trick is wrapping the wheels with cut up ballons or rubber bands, I'm not sure how well the rubber bands would work on your wheels, but the ballon should hold on fine.

As far as springs, with a lot of nuts jammed together to form a stopping point it might be easier to use rubber washers instead, so that could be worth a shot.

The rubber washer would work well, but, I don't think that rubber bands or balloons would help too much, because he already has rubber wheels.
I've cut a piece of sponge and also foam, I think rubber like rubber washers work the best, maybe a few of them.Put the axle through the sponge (cut a small square) if you want to go that route, and the rubber washers are self-explanatory.

InfiniCuber wrote: The rubber washer would work well, but, I don't think that rubber bands or balloons would help too much, because he already has rubber wheels.
I've cut a piece of sponge and also foam, I think rubber like rubber washers work the best, maybe a few of them.Put the axle through the sponge (cut a small square) if you want to go that route, and the rubber washers are self-explanatory.

The latex in the balloons can hold on different surfaces than his rubber wheels. Also it really depends on the durometer of the rubber, it could be really soft (preferred), or really hard which wouldn't grip at all.

gladiolatrue wrote:In the rules, they have a bonus shot option with a tin can, but they don't specify how to go for bonus points. At regionals and states last year, I didn't see any can. Can anyone shed light on this?

There was discussion about the bonus early in the season when the rules were released. Click here to see it, along with a helpful drawing made by iwonder.

iwonder wrote:

InfiniCuber wrote: The rubber washer would work well, but, I don't think that rubber bands or balloons would help too much, because he already has rubber wheels.
I've cut a piece of sponge and also foam, I think rubber like rubber washers work the best, maybe a few of them.Put the axle through the sponge (cut a small square) if you want to go that route, and the rubber washers are self-explanatory.

The latex in the balloons can hold on different surfaces than his rubber wheels. Also it really depends on the durometer of the rubber, it could be really soft (preferred), or really hard which wouldn't grip at all.

This is true. I guess I am going off of what I've used, and I have rubber wheels with a low durometer and are very soft , which helps grip many surfaces. I know i had harder ones before, so I was assuming it still worked well. If the wheels are hard, then youre right, balloons will work! Although it is an annoyance to change them after they begin to rip

if the plastic is hard, is there any way to "soften" it up like sanding?