Time vs. mass
Time vs. mass
How does the time/speed of the car relate to its mass? My car is between 200-300g, and it doesn't seem to go that fast. What kind of mass would you need to get down to a 10 second run time?
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dragonfruit35
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Re: Time vs. mass
The speed of the car doesn't depend solely upon its mass. How big are the wheels on your drive axle? Their size affects their circumference and thus how far they travel with every wind of string.
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- hicanha (Fri Oct 02, 2020 12:16 am)
tjhsst '20
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virginia tech '24
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"it's not a pen, it's a principle!" - annie edison
Re: Time vs. mass
I have 3in wheels currently. How much does drive axle diameter matter? I was planning to switch to a smaller diameter and smaller wheels, but I'm not sure if that would increase speed.dragonfruit35 wrote:The speed of the car doesn't depend solely upon its mass. How big are the wheels on your drive axle? Their size affects their circumference and thus how far they travel with every wind of string.
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falcon1236912
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Re: Time vs. mass
Smaller wheels, a shorter drive arm, and a larger diameter axel will increase speed.sciencecat42 wrote:I have 3in wheels currently. How much does drive axle diameter matter? I was planning to switch to a smaller diameter and smaller wheels, but I'm not sure if that would increase speed.dragonfruit35 wrote:The speed of the car doesn't depend solely upon its mass. How big are the wheels on your drive axle? Their size affects their circumference and thus how far they travel with every wind of string.
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- hicanha (Fri Oct 02, 2020 12:16 am)
Re: Time vs. mass
I get why smaller wheels help (less rotational inertia) and a shorter drive arm helps (less distance for more force) but what does a larger axle do? What if you decrease both wheel and axle size?falcon1236912 wrote:Smaller wheels, a shorter drive arm, and a larger diameter axel will increase speed.sciencecat42 wrote:I have 3in wheels currently. How much does drive axle diameter matter? I was planning to switch to a smaller diameter and smaller wheels, but I'm not sure if that would increase speed.dragonfruit35 wrote:The speed of the car doesn't depend solely upon its mass. How big are the wheels on your drive axle? Their size affects their circumference and thus how far they travel with every wind of string.
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falcon1236912
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Re: Time vs. mass
a larger axel provides more torque and will help increase speed. If you decrease both the wheel size and axel size, the speed would change relative to the new wheel to axel ratio.sciencecat42 wrote:I get why smaller wheels help (less rotational inertia) and a shorter drive arm helps (less distance for more force) but what does a larger axle do? What if you decrease both wheel and axle size?falcon1236912 wrote:Smaller wheels, a shorter drive arm, and a larger diameter axel will increase speed.sciencecat42 wrote:
I have 3in wheels currently. How much does drive axle diameter matter? I was planning to switch to a smaller diameter and smaller wheels, but I'm not sure if that would increase speed.