Scrambler B

[bernard]

Thanks both bernard and fishman100 for the thorough descriptions and tips.

I modified my launcher by slightly altering the locking mechanism and elastic I used, and now it works, but I'm getting around 1.9 seconds from 0.5-8.5 meters. I guess this is decent but clearly you guys have gotten better times, so I'll continue to experiment and modify mine. :D

And lastly, bernard, pictures would indeed be helpful if you'd like to share. Though don't go through too much trouble trying to find them. :)

1.9s in VA will definitely put you at or near the top, but if you want to reduce your time further don't forget about other factors such as friction, car's mass etc.

Okay, that's interesting. I know that VA is not an extremely competitive state, but still...

Also, my car is quite light - about 150 grams without the egg. Based on other posts in past forums this seems lower than the vast majority of cars, so I think I can easily lower my current time substantially.

Great weight. I think last season I was over 500 g with a car made from aluminum angles, only got down to around 150 g after 3D printing, so I'm curious how you're approaching it. We had a lot of skidding with a light vehicle--I think around half a meter or more, I don't really remember but you can hear it at the end of the run (https://www.youtube.com/watch?v=VsXE7l9jpWM).

[InfiniCuber]

1.9s in VA will definitely put you at or near the top, but if you want to reduce your time further don't forget about other factors such as friction, car's mass etc.

Okay, that's interesting. I know that VA is not an extremely competitive state, but still...

Also, my car is quite light - about 150 grams without the egg. Based on other posts in past forums this seems lower than the vast majority of cars, so I think I can easily lower my current time substantially.

Great weight. I think last season I was over 500 g with a car made from aluminum angles, only got down to around 150 g after 3D printing, so I'm curious how you're approaching it. We had a lot of skidding with a light vehicle--I think around half a meter or more, I don't really remember but you can hear it at the end of the run (https://www.youtube.com/watch?v=VsXE7l9jpWM).

This is a very important point. Last year in Scrambler we made such a big deal about bringing the weight of our car down, but the consequences can be massive skidding, as Bernard pointed out. To be quite honest, 1.9 seconds is not only competitive, it's VERY competitive. I can almost guarantee you will win every time with that time as long as you are accurate. Last year at nationals I got a 6th place medal with a time of 2.3 seconds and 17ish cm off. Which isn't a ton accurate (although on the second run i did get within a cm of the wall but i was a bit left). And i had one of the top 5 or so fastest cars there. 1.9 seconds puts you in a very good spot, and in my opinion, you shouldn't try to spend more time bringing this time down. I would fine tune distances and make sure you are consistent with such as speed. Any faster and you'll have a ton of trouble stopping accurately...

[SluffAndRuff]

Okay, that's interesting. I know that VA is not an extremely competitive state, but still...

Also, my car is quite light - about 150 grams without the egg. Based on other posts in past forums this seems lower than the vast majority of cars, so I think I can easily lower my current time substantially.

Great weight. I think last season I was over 500 g with a car made from aluminum angles, only got down to around 150 g after 3D printing, so I'm curious how you're approaching it. We had a lot of skidding with a light vehicle--I think around half a meter or more, I don't really remember but you can hear it at the end of the run (https://www.youtube.com/watch?v=VsXE7l9jpWM).

This is a very important point. Last year in Scrambler we made such a big deal about bringing the weight of our car down, but the consequences can be massive skidding, as Bernard pointed out. To be quite honest, 1.9 seconds is not only competitive, it's VERY competitive. I can almost guarantee you will win every time with that time as long as you are accurate. Last year at nationals I got a 6th place medal with a time of 2.3 seconds and 17ish cm off. Which isn't a ton accurate (although on the second run i did get within a cm of the wall but i was a bit left). And i had one of the top 5 or so fastest cars there. 1.9 seconds puts you in a very good spot, and in my opinion, you shouldn't try to spend more time bringing this time down. I would fine tune distances and make sure you are consistent with such as speed. Any faster and you'll have a ton of trouble stopping accurately...

Hmmm, interesting. My car does indeed skid a lot (up to 50 cm) so I guess I will need to work on consistency.

Also, my car is almost entirely made of balsa with thin metal axles and DVD's for wheels that I scrapped together in about an hour. Only the absolute necessities are on the car, hence the low weight. I'm going to try and make a car out of plastic and aluminum that will hopefully be more consistent, albeit heavier.

[bernard]

Great weight. I think last season I was over 500 g with a car made from aluminum angles, only got down to around 150 g after 3D printing, so I'm curious how you're approaching it. We had a lot of skidding with a light vehicle--I think around half a meter or more, I don't really remember but you can hear it at the end of the run (https://www.youtube.com/watch?v=VsXE7l9jpWM).

This is a very important point. Last year in Scrambler we made such a big deal about bringing the weight of our car down, but the consequences can be massive skidding, as Bernard pointed out. To be quite honest, 1.9 seconds is not only competitive, it's VERY competitive. I can almost guarantee you will win every time with that time as long as you are accurate. Last year at nationals I got a 6th place medal with a time of 2.3 seconds and 17ish cm off. Which isn't a ton accurate (although on the second run i did get within a cm of the wall but i was a bit left). And i had one of the top 5 or so fastest cars there. 1.9 seconds puts you in a very good spot, and in my opinion, you shouldn't try to spend more time bringing this time down. I would fine tune distances and make sure you are consistent with such as speed. Any faster and you'll have a ton of trouble stopping accurately... :D

Hmmm, interesting. My car does indeed skid a lot (up to 50 cm) so I guess I will need to work on consistency.

Also, my car is almost entirely made of balsa with thin metal axles and DVD's for wheels that I scrapped together in about an hour. Only the absolute necessities are on the car, hence the low weight. I'm going to try and make a car out of plastic and aluminum that will hopefully be more consistent, albeit heavier.

I'm concerned a spring launcher may pull your vehicle apart since it seems to be primarily balsa.

[InfiniCuber]

This is a very important point. Last year in Scrambler we made such a big deal about bringing the weight of our car down, but the consequences can be massive skidding, as Bernard pointed out. To be quite honest, 1.9 seconds is not only competitive, it's VERY competitive. I can almost guarantee you will win every time with that time as long as you are accurate. Last year at nationals I got a 6th place medal with a time of 2.3 seconds and 17ish cm off. Which isn't a ton accurate (although on the second run i did get within a cm of the wall but i was a bit left). And i had one of the top 5 or so fastest cars there. 1.9 seconds puts you in a very good spot, and in my opinion, you shouldn't try to spend more time bringing this time down. I would fine tune distances and make sure you are consistent with such as speed. Any faster and you'll have a ton of trouble stopping accurately...

Hmmm, interesting. My car does indeed skid a lot (up to 50 cm) so I guess I will need to work on consistency.

Also, my car is almost entirely made of balsa with thin metal axles and DVD's for wheels that I scrapped together in about an hour. Only the absolute necessities are on the car, hence the low weight. I'm going to try and make a car out of plastic and aluminum that will hopefully be more consistent, albeit heavier.

I'm concerned a spring launcher may pull your vehicle apart since it seems to be primarily balsa.

This is a very real concern. That is a lot of energy being transferred to a light (and soft) material vehicle. I think it would be a safe idea to make it out of plastic. It's lightweight and sturdy. Unless your balsa is made and glued in a very strong and resilient structure, there is always a possibility.

[windu34]

Last year when I did scrambler, I used carbon fiber and printed parts - significantly stronger and still very light (depending on the plastic). I think I got it to weigh about 150-200 grams

[SluffAndRuff]

Last year when I did scrambler, I used carbon fiber and printed parts - significantly stronger and still very light (depending on the plastic). I think I got it to weigh about 150-200 grams

Nice. I personally don't have access to a 3d printer, maybe I can try out some carbon fiber though.

Hmmm, interesting. My car does indeed skid a lot (up to 50 cm) so I guess I will need to work on consistency.

Also, my car is almost entirely made of balsa with thin metal axles and DVD's for wheels that I scrapped together in about an hour. Only the absolute necessities are on the car, hence the low weight. I'm going to try and make a car out of plastic and aluminum that will hopefully be more consistent, albeit heavier.

I'm concerned a spring launcher may pull your vehicle apart since it seems to be primarily balsa.

This is a very real concern. That is a lot of energy being transferred to a light (and soft) material vehicle. I think it would be a safe idea to make it out of plastic. It's lightweight and sturdy. Unless your balsa is made and glued in a very strong and resilient structure, there is always a possibility.

My balsa car doesn't show any signs of damage or anything yet, despite the fact that I've tested it around 50 times, and the fact that it's sloppily hot-glued. I was surprised by this; the balsa, even where it's attached to the elastic and where it's gripped by the bar (to hold in place while mass is falling), literally has no noticeable damage. Not a single piece has fallen off either.

Maybe wear and tear will come with time, so I agree that plastic, aluminum, carbon fiber, etc. are much stronger materials, which is partially why I'm building a new car.

[windu34]

Hot glue is probably one of the worst things you could use: not only does it add significant weight, it is not very strong. Use cyano-acrelate and maybe some small screws.

[SluffAndRuff]

Hot glue is probably one of the worst things you could use: not only does it add significant weight, it is not very strong. Use cyano-acrelate and maybe some small screws.

Yeah, I know. The car wasn't meant to be competition-caliber or anything, I just wanted to make a car that I could test and try out the launcher on. I do have CA glue left over from ELG but it's annoying because of the super-fast drying time, though I will probably use it for future cars.

[InfiniCuber]

Hot glue is probably one of the worst things you could use: not only does it add significant weight, it is not very strong. Use cyano-acrelate and maybe some small screws.

Yeah, I know. The car wasn't meant to be competition-caliber or anything, I just wanted to make a car that I could test and try out the launcher on. I do have CA glue left over from ELG but it's annoying because of the super-fast drying time, though I will probably use it for future cars.

Just as windu34, use carbon fiber and plastic. My car was the same thing when I did Scrambler last year, 3D printed parts with carbon fiber rods. If you don't have access to a 3D printer at your school, then I suggest looking for a service online for cheap 3D printing. You can usually find services that have people lending out their printers that are near your, almost like a 3D printer craig's list. That is if you really want 3D printed parts. But it's worth it, since it is perfectly custom!

CA glue is much better, so it's good that you will use that. It does dry fast, just have it pre-planned and only glue when you are certain where you want pieces.