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Re: Gravity Vehicle C

Posted: October 16th, 2019, 1:21 pm
by knightmoves
Just to explain why the dowel has to be where it is: if the dowel is in the back, and the car is 60 cm long, the second photogate won't be tripped if the car has to travel 9 meters, as the dowel will fall 10 cm short of the laser, so timing won't stop.
The dowel defines the measurement point on the car. If the rules allowed the dowel to be anywhere, it would work fine to have it at the back, because you'd be stopping the back of your car on the 9m mark.

But the rules say that it goes on the front, so that's where it goes.

Re: Gravity Vehicle C

Posted: October 16th, 2019, 2:18 pm
by Lorant
You are correct, you would have a faster time with a shorter device that you described because you would hit the peak velocity earlier. However, the difference in time will not be worth the loss of accuracy you will experience. Larger wheelbases will result in less deviation from the intended path of travel and will be more forgiving in terms of accuracy. In my opinion, you want to maximize wheelbase because the savings in time arent large enough to be worth it. Time is simply not worth nearly as much as accuracy when you consider the tradeoffs.
So to maximize the wheelbase, would it be ideal to make the car as close to 50cm wide as possible?

Re: Gravity Vehicle C

Posted: October 16th, 2019, 7:30 pm
by windu34
You are correct, you would have a faster time with a shorter device that you described because you would hit the peak velocity earlier. However, the difference in time will not be worth the loss of accuracy you will experience. Larger wheelbases will result in less deviation from the intended path of travel and will be more forgiving in terms of accuracy. In my opinion, you want to maximize wheelbase because the savings in time arent large enough to be worth it. Time is simply not worth nearly as much as accuracy when you consider the tradeoffs.
So to maximize the wheelbase, would it be ideal to make the car as close to 50cm wide as possible?
I think you are referring to "track" rather than wheelbase.
Diagram

Re: Gravity Vehicle C

Posted: October 24th, 2019, 8:17 am
by Tendan
Just to explain why the dowel has to be where it is: if the dowel is in the back, and the car is 60 cm long, the second photogate won't be tripped if the car has to travel 9 meters, as the dowel will fall 10 cm short of the laser, so timing won't stop.
The dowel defines the measurement point on the car. If the rules allowed the dowel to be anywhere, it would work fine to have it at the back, because you'd be stopping the back of your car on the 9m mark.

But the rules say that it goes on the front, so that's where it goes.
Other parts of the vehicle could trip the laser before the dowel. That's probably why.

Re: Gravity Vehicle C

Posted: October 24th, 2019, 8:28 pm
by Owenn
Can anyone show me or post a design example? I don't know how to approach this (first year of team and project and everyone)

Re: Gravity Vehicle C

Posted: October 25th, 2019, 5:53 pm
by xiangyu
Can anyone show me or post a design example? I don't know how to approach this (first year of team and project and everyone)
Owenn,

First of all, welcome to Scioly! It's an awesome program and I hope you have lots of fun with it!

To get an overview and good start of the event, check out the Scioly wiki on gravity vehicle: https://scioly.org/wiki/index.php/Gravity_Vehicle

I was glancing through the Scioly forums' summer study session works and found some work on gravity vehicle that can be helpful: https://scioly.org/tests/
Scroll down until you find gravity vehicle or simply do ctrl + f "gravity vehicle". There are some good notes and diagrams to get you started.

Otherwise, look through the forums and ask lots of specific questions! Don't focus too much on the details at the start and just experiment with different things. It is important to keep a log once you start testing as that will help you tune your vehicle.

Good luck and ask if you have questions 8-)
Xiangyu

Re: Gravity Vehicle C

Posted: October 31st, 2019, 1:13 pm
by Raesow
Hey everyone, this is my first time posting on this forum, so sorry if I'm saying something that's already been asked, as I am not entirely sure of the format of this site. My question is, what is your guys interpretation of the part of the rules that says: "Only non-electric sighting/aiming devices are permitted. If placed on the Track, they must be removed before each run. If placed on the Vehicle or Ramp, they may be removed at the team’s discretion. Sighting and aiming devices left on the Vehicle during its run must not cause the Vehicle’s mass to exceed 2.000 kg." 5.f. Does the sighting device count as part of the measurement of the ramp and vehicle? As in, if the sighting device were to extend out of the maximum measurements, would that be legal? Based on this rule, it makes it seem like that can be added and removed whenever needed, so I'm unsure as to if it needs to be attached during the measurements/counts in the measurement.

Re: Gravity Vehicle C

Posted: October 31st, 2019, 4:22 pm
by PM2017
Hey everyone, this is my first time posting on this forum, so sorry if I'm saying something that's already been asked, as I am not entirely sure of the format of this site. My question is, what is your guys interpretation of the part of the rules that says: "Only non-electric sighting/aiming devices are permitted. If placed on the Track, they must be removed before each run. If placed on the Vehicle or Ramp, they may be removed at the team’s discretion. Sighting and aiming devices left on the Vehicle during its run must not cause the Vehicle’s mass to exceed 2.000 kg." 5.f. Does the sighting device count as part of the measurement of the ramp and vehicle? As in, if the sighting device were to extend out of the maximum measurements, would that be legal? Based on this rule, it makes it seem like that can be added and removed whenever needed, so I'm unsure as to if it needs to be attached during the measurements/counts in the measurement.
Per rule 3.f., the Vehicle and Ramp only need to fit in the dimension parameters in the "ready-to-run" configuration, which is essentially the state in which the vehicle and ramp are sitting in, "waiting" for you to trigger the device. This means that you'd have already removed the sighting device by the time you get to the ready-to-run configuration (assuming you are, indeed, removing the sighting mechanisms). So, the sighting mech. isn't included in the measured dimensions.

Also -- welcome to the forums! It's always great getting new members of the community!

Re: Gravity Vehicle C

Posted: November 3rd, 2019, 1:43 pm
by Otkrlj
Hey what does everyone think times will be like at nats this year?

Re: Gravity Vehicle C

Posted: November 3rd, 2019, 8:54 pm
by Pranoob
Hey everyone, this is my first time posting on this forum, so sorry if I'm saying something that's already been asked, as I am not entirely sure of the format of this site. My question is, what is your guys interpretation of the part of the rules that says: "Only non-electric sighting/aiming devices are permitted. If placed on the Track, they must be removed before each run. If placed on the Vehicle or Ramp, they may be removed at the team’s discretion. Sighting and aiming devices left on the Vehicle during its run must not cause the Vehicle’s mass to exceed 2.000 kg." 5.f. Does the sighting device count as part of the measurement of the ramp and vehicle? As in, if the sighting device were to extend out of the maximum measurements, would that be legal? Based on this rule, it makes it seem like that can be added and removed whenever needed, so I'm unsure as to if it needs to be attached during the measurements/counts in the measurement.
Per rule 3.f., the Vehicle and Ramp only need to fit in the dimension parameters in the "ready-to-run" configuration, which is essentially the state in which the vehicle and ramp are sitting in, "waiting" for you to trigger the device. This means that you'd have already removed the sighting device by the time you get to the ready-to-run configuration (assuming you are, indeed, removing the sighting mechanisms). So, the sighting mech. isn't included in the measured dimensions.

Also -- welcome to the forums! It's always great getting new members of the community!
What's an example of a useful sighting device for this event?