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Re: Gravity Vehicle C
Posted: February 9th, 2012, 11:13 am
by JTMess
If your car is consistently with 10 cm of the target point, that's a very respectable score. The winner of our regional competition was actually about 5 cm off, although the winner of states in New York will definitely be within a couple of centimeters.
Another thing to consider is the time your car takes to run. If it is accurate but takes a long time (more than 5 or so seconds) then you will lose a lot of points on the time and would benefit from finding wheels with less traction. Hope this helps!
Re: Gravity Vehicle C
Posted: February 10th, 2012, 2:46 pm
by JTMess
sj, what thickness lexan are you using for your chassis? We used 1/8 inch for our ramp at regionals and found that it easily deformed, although we're considering it for our chassis at states.
Re: Gravity Vehicle C
Posted: February 11th, 2012, 6:39 pm
by sj
We are using 1/8th. At tiger today we placed 4th with a fast and accurate time (didn't get to see what it was exactly) but we were off by 9cm (mostly because we were solving the equations for our car in our heads as we forgot to impound a calculator)
Re: Gravity Vehicle C
Posted: February 11th, 2012, 7:26 pm
by questionguy
sj wrote:We are using 1/8th. At tiger today we placed 4th with a fast and accurate time (didn't get to see what it was exactly) but we were off by 9cm (mostly because we were solving the equations for our car in our heads as we forgot to impound a calculator)
How exactly does one find an equation for their car. Do you just use the line of best fit from data?
or do you just plug in for the circumference of the wheel?
Re: Gravity Vehicle C
Posted: February 11th, 2012, 7:31 pm
by sj
We do it based on a variety of data including distance, revolutions, and time among others. Then we relate everything with a system of equations.
Re: Gravity Vehicle C
Posted: February 12th, 2012, 5:33 am
by fishman100
SJ do you know your score and the winning team's (Rustin) score? I looked at the score sheet that was included in the CD files of the tests, etc. and it said ~513 was the final score, but I doubt that's correct.
Re: Gravity Vehicle C
Posted: February 12th, 2012, 5:43 am
by sj
Not sure about Rustin, but our score was 284 I believe... this was a bit disappointing because at Consetoga we got a score of 194 on a very similar surface and distance.
Re: Gravity Vehicle C
Posted: February 13th, 2012, 6:53 pm
by curly657
Rule 3b it says that the ramp must include a release mechanism,
which is not part of the vehicle to hold the vehicle in place..
We are using a bolt for our release mechanism. The actual "switch" is part of the ramp, but there is a part at the back of the car where the bolt is inserted.
Do you think this would violate rule 3b? Would they consider the holder as part of the release mechanism?
Here is a picture of the release mechanism. The actual bolt which is on the right side is part of the ramp, but the part that holds the bolt (on the left) is attached to the car.
http://www.google.com/imgres?um=1&hl=en ... 9,r:14,s:0
Thanks

Re: Gravity Vehicle C
Posted: February 13th, 2012, 7:36 pm
by sachleen
curly657 wrote:Rule 3b it says that the ramp must include a release mechanism,
which is not part of the vehicle to hold the vehicle in place..
We are using a bolt for our release mechanism. The actual "switch" is part of the ramp, but there is a part at the back of the car where the bolt is inserted.
Do you think this would violate rule 3b? Would they consider the holder as part of the release mechanism?
Here is a picture of the release mechanism. The actual bolt which is on the right side is part of the ramp, but the part that holds the bolt (on the left) is attached to the car.
http://www.google.com/imgres?um=1&hl=en ... 9,r:14,s:0
Thanks

There has to be some way to hold the vehicle to the ramp. I would not raise any issue with that setup (usual disclaimer). Especially since the actual mechanism to release the vehicle is attached to the ramp and, based on how you're most likely going to attach the bolt, there's no way for you to "hold, constrain, or give a push to the vehicle" by actuating the mechanism. I think as long as you don't directly have to touch the vehicle with the pencil to launch it, it should be fine.
Re: Gravity Vehicle C
Posted: February 13th, 2012, 7:44 pm
by bearasauras
I would think that it would be fine as long as there is a release mechanism permanently attached to the ramp. I mean the vehicle should be okay with having components that are specifically intended to interact with the release mechanism on the ramp, as long as the release mechanism cannot be 100% on board the vehicle.....but then I don't know much about this event, so don't take my words for it.