Gravity Vehicle C

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illusionist
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Re: Gravity Vehicle C

Post by illusionist »

On a similar topic, wouldn't it be ideal to make the vehicle out of a light material and then focus the rest of the available mass towards the back of the vehicle (the point that will be highest from the ground)? I was planning on making the body out of plastic or thicker balsa wood. Metal was not something that I had even considered.
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Re: Gravity Vehicle C

Post by Balsa Man »

illusionist wrote:On a similar topic, wouldn't it be ideal to make the vehicle out of a light material and then focus the rest of the available mass towards the back of the vehicle (the point that will be highest from the ground)? I was planning on making the body out of plastic or thicker balsa wood. Metal was not something that I had even considered.
You're thinking along the right lines....
What the best answer those lines lead to will emerge as the season rolls on.
Yes, I believe there are good reasons to build the chassis light (but it still has to be strong and stiff) so you can concentrate mass.....in the right place(s)
Given that you want the center of mass to start as high up as you can, and come off the ramp as low down as you can (i.e., close to the floor), and, I believe, if you have it too concentrated at the back (where the front wheels are too lightly loaded) its going to have trouble going consistently straight - this presents an interesting challenge.
Viable possibilities include balsa, aluminum, some plastics, carbon fiber, combinations.
Lots of trade-offs and balancing various factors to be considered!
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Re: Gravity Vehicle C

Post by questionguy »

In order to make a curved ramp, how does one curve the wood without it breaking?
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Re: Gravity Vehicle C

Post by chalker7 »

questionguy wrote:In order to make a curved ramp, how does one curve the wood without it breaking?
If you use thin wood (1/8" sheet) it will bend without breaking when screwed down to a rigid frame.
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Re: Gravity Vehicle C

Post by questionguy »

chalker7 wrote:
questionguy wrote:In order to make a curved ramp, how does one curve the wood without it breaking?
If you use thin wood (1/8" sheet) it will bend without breaking when screwed down to a rigid frame.
Gotcha, thanks!
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Re: Gravity Vehicle C

Post by illusionist »

questionguy wrote:
chalker7 wrote:
questionguy wrote:In order to make a curved ramp, how does one curve the wood without it breaking?
If you use thin wood (1/8" sheet) it will bend without breaking when screwed down to a rigid frame.
Gotcha, thanks!
You can also mist or wet the wood. However this may lead to warping when it dries, unless it is screwed down firmly. (I think, no solid evidence)
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Re: Gravity Vehicle C

Post by chalker7 »

illusionist wrote: You can also mist or wet the wood. However this may lead to warping when it dries, unless it is screwed down firmly. (I think, no solid evidence)
I wouldn't try this, if you use thin enough wood (such as particleboard), you shouldn't have any trouble fitting it to a curve. Soaking the wood will cause a mess and you cannot really control the final shape after drying particularly well.
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Target distance question

Post by curly657 »

Hi everyone,
I am new to building events. I have a question on Rule 3a
It says that the vehicles must be designed to travel between 5-10m. But then it says that the Event supervisor will determine the exact distance after the all vehicles are impounded.
I dont understand how this works. Let us say that you designed the vehicle to travel 9m from the base of the ramp and the event supervisor decides that the target distance is 5.5m. Then, are you out of luck that you designed your vehicle to travel 9m ? This does't seem to make sense ?
Are you allowed to change the position of the base of your ramp and move it away from the start line such that it will stop close to the 5.5m point in the example above ?

Thanks
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Re: Target distance question

Post by chalker »

curly657 wrote:Hi everyone,
I am new to building events. I have a question on Rule 3a
It says that the vehicles must be designed to travel between 5-10m. But then it says that the Event supervisor will determine the exact distance after the all vehicles are impounded.
I dont understand how this works. Let us say that you designed the vehicle to travel 9m from the base of the ramp and the event supervisor decides that the target distance is 5.5m. Then, are you out of luck that you designed your vehicle to travel 9m ? This does't seem to make sense ?
Are you allowed to change the position of the base of your ramp and move it away from the start line such that it will stop close to the 5.5m point in the example above ?

Thanks
You need to design your vehicle to be adjustable (i.e. it can stop at any distance between 5-10 m). You are given some time to setup and adjust your vehicle during the competition.

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Re: Target distance question

Post by chalker7 »

curly657 wrote:Hi everyone,
I am new to building events. I have a question on Rule 3a
It says that the vehicles must be designed to travel between 5-10m. But then it says that the Event supervisor will determine the exact distance after the all vehicles are impounded.
I dont understand how this works. Let us say that you designed the vehicle to travel 9m from the base of the ramp and the event supervisor decides that the target distance is 5.5m. Then, are you out of luck that you designed your vehicle to travel 9m ? This does't seem to make sense ?
Are you allowed to change the position of the base of your ramp and move it away from the start line such that it will stop close to the 5.5m point in the example above ?

Thanks
It means you have to design an adjustable braking system. You design your vehicle to travel anywhere between 5 and 10 m and then adjust it for the announced distance during your competition time. Check out the wiki for some ideas about how to do this.
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