nctarheel wrote:I am very new to the Electric Vehicle, as it was kind of thrust upon me this year by the club adviser. There are a few questions that I have about this event that I was not able to find answers to at the North Carolina and US Science Olympiad web pages:
1) Are you judged any at all on how fast your vehicle travels the assigned distance?
2) Would I be penalized for using 4 D Cell batteries?
3) What is a good way to brake the vehicle in a straight line? I was thinking a front-drive, rear brake system would be more stable, kind of like on bicycles (without the front-drive).
4) Is weight factored into the score?
5) Which of these combinations would work best?
-Low-riding body
-High-riding body
-Slender-width body
-Wide-width body
-Long-length body
-Short-length body
-Wide axle/tire track
1. At regional and state competition you only have to ensure that the travel time is within the acceptable limits, less than 45 seconds. Of course you have to be able to predict the travel time accurately since that is 1/4 of the total possible point. At National competition you must adjust the speed to match what the event coordinator specifies.
2 As long as their voltage is labeled as 1.5 volts or less, you can use up to 4 batteries of any type you choose
3. As long as you don't lock up the wheels during breaking it makes little difference which wheels you use. If you are going to use the old screw and wingnut break then it should go on the front. It may seem a bit unintuitive but locking the front wheels on a vehicle (car for example) is less likely to cause an instability.
4. Weight is not factored in any way.
5. The rules this year make allow little choice of length and width. WHeelbase must be within a narrow range. Maximum track (measured to the outside of the wheels) is in the rules, and most people would probably want to have the track as wide as possible in order to maximise the chances of getting the Center Line Score. As to the body, I cannot see any reason why it would make any difference. The speed at which the vehicle must travel is quite slow (at least is can be) so there is little likelyhood of instability due to high CG, understeer, oversteer or other slip angle issues. Aerodynamics will be virtually insignificant at the speeds required.
-Slender axle/tire track
Thanks for the help!
1. At regional and state competition you only have to ensure that the travel time is within the acceptable limits, less than 45 seconds. Of course you have to be able to predict the travel time accurately since that is 1/4 of the total possible point. At National competition you must adjust the speed to match what the event coordinator specifies.
2 As long as their voltage is labeled as 1.5 volts or less, you can use up to 4 batteries of any type you choose
3. As long as you don't lock up the wheels during breaking it makes little difference which wheels you use. If you are going to use the old screw and wingnut break then it should go on the front. It may seem a bit unintuitive but locking the front wheels on a vehicle (car for example) is less likely to cause an instability.
4. Weight is not factored in any way.
5. The rules this year make allow little choice of length and width. WHeelbase must be within a narrow range. Maximum track (measured to the outside of the wheels) is in the rules, and most people would probably want to have the track as wide as possible in order to maximise the chances of getting the Center Line Score. As to the body, I cannot see any reason why it would make any difference. The speed at which the vehicle must travel is quite slow (at least is can be) so there is little likelyhood of instability due to high CG, understeer, oversteer or other slip angle issues. Aerodynamics will be virtually insignificant at the speeds required.
. They use rechargeable and I'm thinking of doing the same. Are there still size D rechargeable batteries? And would it be better if put a 5v regulator in line with the batteries to the microcontroller so there always a consistent voltage? Are there any problems with a regulator? 
