Gravity Vehicle C

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Primate
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Re: Gravity Vehicle C

Post by Primate »

starpug wrote:Thing is with Mousetrap you were playing with the wheel to axle ratio so you wanted small wheels on the powered axle. With Gravity Vehicle I'm thinking you may want bigger wheels because that can handle the transfer from ramp to floor better. That depends on your ramp though. Smaller wheels might however move closer to a curve though. This is something I'm probably going to want to test out.
I'm really thinking wheel size won't matter much, especially if you flatten your ramp out at the end. My bet is once you get to a certain speed, accuracy is going to matter a whole lot more.

Actually, on second thought, does wheel size affect accuracy? Assuming you place them straight, obviously.
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Re: Gravity Vehicle C

Post by Frogger4907 »

Also remember, The smaller the wheels the closer the weight will get to the floor as it drops down the ramp, giving you slightly more gravitational energy.
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Re: Gravity Vehicle C

Post by sj »

Primate wrote:Actually, on second thought, does wheel size affect accuracy? Assuming you place them straight, obviously.
I believe that wheel size will effect your accuracy because the smaller your wheels the more revolutions necessary to go a certain distance. Thus you have more precise control over your accuracy.

Lets consider a car with wheels of 10 cm circumference and a car with wheels of 25 cm circumference. if the target distance is 5 meters (500 cm) then the first car needs to have 50 revolutions while the second car needs to have 20 revolutions. Then you can see that a difference of say 1 revolution in the set up of the brake will have a much higher impact on the larger diameter wheel. Now once you factor in the skid of the wheels and all as well the more precise your control over the brake distance the better.

In addition smaller wheels will give you a marginal advantage as Frogger said in getting the car lower and maximizing the velocity.
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Re: Gravity Vehicle C

Post by buzzbuzz »

However, with smaller wheels, your car won't carry as well because of the additional energy lost as friction from the extra revolutions. Small wheels could put you at a disadvantage on the longer distances. There's going to be some ideal size. Also, depending on the nature of your braking system, larger wheels could be just as accurate.
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Re: Gravity Vehicle C

Post by engineeringmaniac »

The wheel size depends on your ramP and brake system. That being said, what are your guys' thoughts on braking systems? Obviously the wingnut will still be popular...
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Re: Gravity Vehicle C

Post by Frogger4907 »

engineeringmaniac wrote:The wheel size depends on your ramP and brake system. That being said, what are your guys' thoughts on braking systems? Obviously the wingnut will still be popular...
I'm definitely thinking putting string around both axles that's attached so they both stop at the same time, which gets double the stopping power. The skidding should be consistent.
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Re: Gravity Vehicle C

Post by bearasauras »

I think your skidding is only going to be consistent for a particular floor. Whenever you go to a different type of track, your skidding will normally be slightly off.
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Re: Gravity Vehicle C

Post by Dabbler »

Even so the difference in skid would be fairly minimal + you can calibrate on different floors so you can account for skid.
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Re: Gravity Vehicle C

Post by haverstall »

Calibrate? Unless you go to the competition area the week before, calibration is going to be hard.

2 years ago, for mousetrap, we had perfectly calibrated the MTV for our school's floor, but at the state competition, we missed the line by around 10 cm. And the floor apparently was level. And it looked exactly like our school's floor.
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Re: Gravity Vehicle C

Post by Dabbler »

If it is the same material, I see that as user error or it got bumped during transport.
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