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darkwinters wrote:Just a question (and this may have been clarified earlier): If we're allowed to use variable resistors (i.e. potentiometers/rheostats), what is the point of the rule disallowing integrated circuits?

We generally don't like to allow ICs in event because it opens up the door to microprocessors and computers being allowed, at which point the cost of things seem to sky rocket just to be competitive and it's a lot harder to verify that the students actually built things and understand how they work.

Hey guys do you think ducted fan like this one would work well?

http://www.hobbylinc.com/htm/gws/gwsgwe ... fgodMmAAkA

What's your take on the time (5-15s)? Is it in one second increments, half second increments or what?

joeyjoejoe wrote:What's your take on the time (5-15s)? Is it in one second increments, half second increments or what?

The invitational I went to had a time of 10.2 seconds, and I'd assume any time is allowed since no increment is specified in the rules.

Regionals here set a time of 12 seconds, half the teams we saw there didn't even bring a vehicle and the other half had vehicles that either had a host of violations or didn't run, ours had a motor burn out in the middle of the event and we still got a score of 84 despite our time being only 7.3 seconds, and having to remove half the weight (we had no idea how fast it would go :\). At 995 grams we STILL destroyed every other team with hardly any competition.

Quick question, when the rules state vehicle mass/mass of heaviest vehicle that ran does it mean the heaviest vehicle that ran out of all the teams? Because that's how i interpreted it, but our score would be the same anyways since ours was the heaviest vehicle at the competition.. Also, can the mass score for our team come from a different vehicle than the time score, since we are allowed to bring two vehicles?

TheGatesofLogic wrote: Quick question, when the rules state vehicle mass/mass of heaviest vehicle that ran does it mean the heaviest vehicle that ran out of all the teams? Because that's how i interpreted it, but our score would be the same anyways since ours was the heaviest vehicle at the competition.. Also, can the mass score for our team come from a different vehicle than the time score, since we are allowed to bring two vehicles?

yes and yes. Standard caveat about this not being the place for official clarifications or statements though....

TheGatesofLogic wrote:Regionals here set a time of 12 seconds, half the teams we saw there didn't even bring a vehicle and the other half had vehicles that either had a host of violations or didn't run, ours had a motor burn out in the middle of the event and we still got a score of 84 despite our time being only 7.3 seconds, and having to remove half the weight (we had no idea how fast it would go :\). At 995 grams we STILL destroyed every other team with hardly any competition.

Quick question, when the rules state vehicle mass/mass of heaviest vehicle that ran does it mean the heaviest vehicle that ran out of all the teams? Because that's how i interpreted it, but our score would be the same anyways since ours was the heaviest vehicle at the competition.. Also, can the mass score for our team come from a different vehicle than the time score, since we are allowed to bring two vehicles?

Wow! Congratulations! If you do the math, you must've literally aced the test!

Well, actually we did ace the test, it was 9 questions long, only included the most basic of magnetism concepts (earnshaw's theorem, history of maglev, and magnetic force on a wire with a current running through it basically) and the last two questions were:

8. Without lifting your pencil from the paper draw a giraffelant (I'm pretty sure that's supposed to be a giraffe mixed with an elephant)
9. Write down your best joke about magnetism

the last one we responded with "The grader's life"

I was really disappointed all in all. I expected a much more difficult test, and was prepared for such :\ Really though concepts involving magnetism aren't that hard once you wrap your head around the idea that the magnetic fields are only half of the picture when discussing electromagnetism, which includes electrostatic fields as well, in one sense you can imagine magnetism as an extension of electrostatics but with relative motions.

Does anyone know why brushless motors (as in, say, a PC fan) are disallowed? I understand the ban on ICs, but brushless motors work fine without them...or at least that has been my experience in testing PC fans.

Drew Bronson wrote:Does anyone know why brushless motors (as in, say, a PC fan) are disallowed? I understand the ban on ICs, but brushless motors work fine without them...or at least that has been my experience in testing PC fans.

Brushless motors use internal ICs instead of brushes/commutator to switch the current, thus violating the "no ICs" rule.