Braking

jinhusong
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Re: Braking

Post by jinhusong » February 5th, 2020, 11:54 am

Our gravity vehicle is 1.8 kg. Almost no skidding. Time 3.5 seconds, maybe the speed makes big difference. The brake is at rear wheels because our gravity center is quite close to the back end. Every time after stop, we have to use pliers to get the wingnut loose.

We are using 1 3/8 orange wheels with 4 mm rod. They mailed the wrong size wheels, we just decide to take them and try.

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Re: Braking

Post by MoMoney$$$;)0) » February 5th, 2020, 2:46 pm

jinhusong wrote:
February 5th, 2020, 11:54 am
Our gravity vehicle is 1.8 kg. Almost no skidding. Time 3.5 seconds, maybe the speed makes big difference. The brake is at rear wheels because our gravity center is quite close to the back end. Every time after stop, we have to use pliers to get the wingnut loose.

We are using 1 3/8 orange wheels with 4 mm rod. They mailed the wrong size wheels, we just decide to take them and try.

Tiger
To be fair, I don't understand why this is an issue. Your vehicle seems to be doing well, since this tight breaking means you have a lot of momentum on your car, and that's a good sign. Moreover, you can probably do even better with testing, but no need for change; just deal with it is what I would recommend. However, if you really want to change this I would suggest lessening the weight of the car as a whole to have less friction on the wheels, or just try not using a wingnut to use for breaking, and maybe try a different type of "mechanism", similar to a wingnut to use.
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Re: Braking

Post by sciolyperson1 » February 5th, 2020, 4:35 pm

MoMoney$$$;)0) wrote:
February 5th, 2020, 2:46 pm
jinhusong wrote:
February 5th, 2020, 11:54 am
Our gravity vehicle is 1.8 kg. Almost no skidding. Time 3.5 seconds, maybe the speed makes big difference. The brake is at rear wheels because our gravity center is quite close to the back end. Every time after stop, we have to use pliers to get the wingnut loose.

We are using 1 3/8 orange wheels with 4 mm rod. They mailed the wrong size wheels, we just decide to take them and try.

Tiger
To be fair, I don't understand why this is an issue. Your vehicle seems to be doing well, since this tight breaking means you have a lot of momentum on your car, and that's a good sign. Moreover, you can probably do even better with testing, but no need for change; just deal with it is what I would recommend. However, if you really want to change this I would suggest lessening the weight of the car as a whole to have less friction on the wheels, or just try not using a wingnut to use for breaking, and maybe try a different type of "mechanism", similar to a wingnut to use.
Tight braking was an issue for us with our 2nd buggy, so much so that we actually didn't use that car because it was too fast and the wingnut actually locked onto the stopper. A slower, more consistently stopping one is preferable.

What MoMoney said about the mass on the car is wrong. You never want to reduce friction on the wheels - this is what keeps vertical distance consistent. As jinhusong said, he has almost no skidding - this is probably due to the time being 3.5 seconds, NOT due to his car being 1800g. Try switching out your axle for one with more TPI if possible - this will alleviate forces that lodge the wingnut and stopper together.

I've actually never heard of any stopping mechanism other than a wingnut stopper that works as as consistently as it is. Try sticking with that, don't try anything different (season's already half over).

Hope that helps.
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Re: Braking

Post by MTV<=>Operator » February 5th, 2020, 4:53 pm

sciolyperson1 wrote:
February 5th, 2020, 4:35 pm
MoMoney$$$;)0) wrote:
February 5th, 2020, 2:46 pm
jinhusong wrote:
February 5th, 2020, 11:54 am
Our gravity vehicle is 1.8 kg. Almost no skidding. Time 3.5 seconds, maybe the speed makes big difference. The brake is at rear wheels because our gravity center is quite close to the back end. Every time after stop, we have to use pliers to get the wingnut loose.

We are using 1 3/8 orange wheels with 4 mm rod. They mailed the wrong size wheels, we just decide to take them and try.

Tiger
To be fair, I don't understand why this is an issue. Your vehicle seems to be doing well, since this tight breaking means you have a lot of momentum on your car, and that's a good sign. Moreover, you can probably do even better with testing, but no need for change; just deal with it is what I would recommend. However, if you really want to change this I would suggest lessening the weight of the car as a whole to have less friction on the wheels, or just try not using a wingnut to use for breaking, and maybe try a different type of "mechanism", similar to a wingnut to use.
Tight braking was an issue for us with our 2nd buggy, so much so that we actually didn't use that car because it was too fast and the wingnut actually locked onto the stopper. A slower, more consistently stopping one is preferable.

What MoMoney said about the mass on the car is wrong. You never want to reduce friction on the wheels - this is what keeps vertical distance consistent. As jinhusong said, he has almost no skidding - this is probably due to the time being 3.5 seconds, NOT due to his car being 1800g. Try switching out your axle for one with more TPI if possible - this will alleviate forces that lodge the wingnut and stopper together.

I've actually never heard of any stopping mechanism other than a wingnut stopper that works as as consistently as it is. Try sticking with that, don't try anything different (season's already half over).

Hope that helps.
What time has your vehicle been getting, if you don't mind sharing? (I see you have been quite successful in this event). It seems as though the main problem with my vehicle is that it goes too fast (2.5 second time). Is there a good way to slow down the vehicle in order to reduce skid? I have the mass concentrated towards the front of my vehicle (where the braking axle is) and it still shifts when the wingnut locks.
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Re: Braking

Post by sciolyperson1 » February 5th, 2020, 5:24 pm

MTV<=>Operator wrote:
February 5th, 2020, 4:53 pm
sciolyperson1 wrote:
February 5th, 2020, 4:35 pm
MoMoney$$$;)0) wrote:
February 5th, 2020, 2:46 pm


To be fair, I don't understand why this is an issue. Your vehicle seems to be doing well, since this tight breaking means you have a lot of momentum on your car, and that's a good sign. Moreover, you can probably do even better with testing, but no need for change; just deal with it is what I would recommend. However, if you really want to change this I would suggest lessening the weight of the car as a whole to have less friction on the wheels, or just try not using a wingnut to use for breaking, and maybe try a different type of "mechanism", similar to a wingnut to use.
Tight braking was an issue for us with our 2nd buggy, so much so that we actually didn't use that car because it was too fast and the wingnut actually locked onto the stopper. A slower, more consistently stopping one is preferable.

What MoMoney said about the mass on the car is wrong. You never want to reduce friction on the wheels - this is what keeps vertical distance consistent. As jinhusong said, he has almost no skidding - this is probably due to the time being 3.5 seconds, NOT due to his car being 1800g. Try switching out your axle for one with more TPI if possible - this will alleviate forces that lodge the wingnut and stopper together.

I've actually never heard of any stopping mechanism other than a wingnut stopper that works as as consistently as it is. Try sticking with that, don't try anything different (season's already half over).

Hope that helps.
What time has your vehicle been getting, if you don't mind sharing? (I see you have been quite successful in this event). It seems as though the main problem with my vehicle is that it goes too fast (2.5 second time). Is there a good way to slow down the vehicle in order to reduce skid? I have the mass concentrated towards the front of my vehicle (where the braking axle is) and it still shifts when the wingnut locks.
Car's 650g (never added weight). 2.964 seconds at MIT.

Slow down the car by lowering your car starting point on the ramp and remove mass from your car to reduce skid and time. Distance is always more important than time.

Usually mass would be added at the back of the car to optimize potential energy - if you can, maybe move it a bit back so it is a 1/3 of the way between the front and back (towards the front).
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Re: Braking

Post by AugustW » March 9th, 2020, 10:48 am

Can someone send a picture of there breaking system. I don't know how to rebuild a spring breaking system for states without 3d printing. I do not have access to a 3d printer, so I do not know how to make the parts in order to do the spring helped wingnut breaking system. Also, do you have any specific springs to recommend? Thanks.

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Re: Braking

Post by CPScienceDude » March 9th, 2020, 10:52 am

AugustW wrote:
March 9th, 2020, 10:48 am
Can someone send a picture of there breaking system. I don't know how to rebuild a spring breaking system for states without 3d printing. I do not have access to a 3d printer, so I do not know how to make the parts in order to do the spring helped wingnut breaking system. Also, do you have any specific springs to recommend? Thanks.
I'll say it again here, "This isn't a place to ask for pictures of a build. I'll give some suggestions though. For braking, I believe the agreed best right now is a wingnut braking system. See Here."
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Re: Braking

Post by AugustW » March 10th, 2020, 11:20 am

CPScienceDude wrote:
March 9th, 2020, 10:52 am
AugustW wrote:
March 9th, 2020, 10:48 am
Can someone send a picture of there breaking system. I don't know how to rebuild a spring breaking system for states without 3d printing. I do not have access to a 3d printer, so I do not know how to make the parts in order to do the spring helped wingnut breaking system. Also, do you have any specific springs to recommend? Thanks.
I'll say it again here, "This isn't a place to ask for pictures of a build. I'll give some suggestions though. For braking, I believe the agreed best right now is a wingnut braking system. See Here."
Other people took pictures. Im just looking for advice, no need to overreact. :D :lol: :lol:
viewtopic.php?f=315&t=17063

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Re: Braking

Post by ndkuma01 » May 28th, 2020, 5:54 pm

I am completely new to the event and new to division C as I am now switching from B to C. And I was reading through the Scioly wiki to get an understanding and I read that the using a wingnut break can have some friction and I wanted to ask if you could use graphite on the nut to reduce friction? I may be getting it wrong be I am just curious and still trying to figure it out.

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Re: Braking

Post by CPScienceDude » May 28th, 2020, 8:08 pm

ndkuma01 wrote:
May 28th, 2020, 5:54 pm
I am completely new to the event and new to division C as I am now switching from B to C. And I was reading through the Scioly wiki to get an understanding and I read that the using a wingnut break can have some friction and I wanted to ask if you could use graphite on the nut to reduce friction? I may be getting it wrong be I am just curious and still trying to figure it out.
You certainly can, but I've personally never used it. The friction between two metal surfaces (the nut and the axle) really isn't that impactful to the overall speed of the vehicle. Plus, if your vehicle is too fast it will skid when braking, and you generally want to avoid skid altogether, as it will make it more challenging to accurately aim your vehicle.
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